User’s Guide
August 1999
Mixed-Signal Products
SLOU051A
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Preface
Related Documentation From Texas Instruments
TI Plug-N-Play Audio Amplifier Evaluation Platform (TI Literature
Number SLOU011) provides detailed information on the evaluation
platform and its use with TI audio evaluation modules.
TPA005D12 CLASS-D STEREO AUDIO POWER AMPLIFIER
(TI Literature Number SLOS246) This is the data sheet for the
TPA005D12 audio amplifier integrated circuit.
Design Considerations for Class-D Audio Power Amplifiers,
(TI Literature Number SLOA031) This application report provides
detailed information on designing audio power amplifier systems
using TI class-D amplifier ICs
Reducing and Eliminating the Class-D Output Filter,
(TI Literature Number SLOA023) This application report covers
output filter theory and design for class-D audio power amplifiers.
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.
Trademarks
TI is a trademark of Texas Instruments Incorporated.
PowerPAD is a trademark of Texas Instruments Incorporated.
iii
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iv
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Contents
1
2
3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1
1.2
1.3
Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
TPA005D12 Class-D EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1
2.2
2.3
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Quick Start List for Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Quick Start List for Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1
3.2
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module . . . . . . . . . . . . . . . 3-3
3.2.1 TPA005D12 Class-D Stereo Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.2.2 Overview of Class-D Audio Amplifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3.2.3 Bridge-Tied Load (BTL) Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
3.2.4 Class-D Differential Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.5 Control and Indicator Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.6 TPA005D12 Class-D EVM Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Class-D Amplifier Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform . . . . . . . . . . . . . 3-11
3.4.1 Installing and Removing EVM Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
3.4.2 Module Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.4.3 Signal Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
3.4.4 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.4.5 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
3.4.6 Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Using The TPA005D12 Class-D EVM Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
3.5.1 Power Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
3.5.2 Input Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
3.5.3 Output Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
3.5.4 Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
TPA005D12 Class-D EVM Performance Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 3-20
TPA005D12 Class-D EVM Interconnects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
TPA005D12 Class-D EVM Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
TPA005D12 Class-D EVM Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
3.3
3.4
3.5
3.6
3.7
3.8
3.9
3.10 TPA005D12 Class-D EVM PCB Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
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Figures
1–1
1–2
2–1
3–1
3–2
3–3
3–4
3–5
3–6
3–7
3–8
3–9
The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View . . . . . . . . . 1-3
The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Bottom View . . . . . . 1-3
Quick Start Platform Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
The TI Plug-N-Play Audio Amplifier Evaluation Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View . . . . . . . . . 3-4
The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Bottom View . . . . . . 3-4
TPA005D12 Class-D EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Class-D Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Class-D Input and Output Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Platform Signal Routing and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Mute/Mode and Polarity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Typical Headphone Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
3–10 TPA005D12 Class-D EVM Stand-Alone Connections for Stereo BTL Output . . . . . . . . . 3-18
3–11 Class-D Amplifier Frequency Response at 4 Ω . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
3–12 Class-D Amplifier Distortion versus Output Power at 4 Ω . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
3–13 Class-D Amplifier Distortion versus Output Power at 8 Ω . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
3–14 Class-D Amplifier Distortion versus Frequency at 1 W Into 4 Ω. . . . . . . . . . . . . . . . . . . . . 3-22
3–15 Class-D Amplifier Distortion versus Frequency at 1 W Into 8 Ω. . . . . . . . . . . . . . . . . . . . . 3-22
3–16 Class-D Amplifier Crosstalk versus Frequency at 2 W Into 4 Ω. . . . . . . . . . . . . . . . . . . . . 3-23
3–17 Class-D Amplifier Crosstalk versus Frequency at 2 W Into 8 Ω. . . . . . . . . . . . . . . . . . . . . . 3-23
3–18 TPA005D12 Class-D EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
3–19 TPA005D12 Class-D EVM Top Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
3–20 TPA005D12 Class-D EVM Bottom Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
3–21 TPA005D12 Class-D EVM Top Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
3–22 TPA005D12 Class-D EVM Second Layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
3–23 TPA005D12 Class-D EVM Third Layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
3–24 TPA005D12 Class-D EVM Bottom Layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
Tables
2–1
Typical TI Plug-N-Play Platform Jumper and Switch Settings for the
TPA005D12 Class-D EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2–2
3–1
3–2
3–3
3–4
3–5
Platform Jumper and Switch Settings for the TPA005D12 . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
TPA005D12 Class-D EVM Fault Indicator Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
TPA005D12 Class-D EVM Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Platform Jumper and Switch Settings for the TPA005D12 EVM Power Inputs . . . . . . . . 3-16
TPA005D12 Class-D EVM/Plug-N-Play Platform Interconnects . . . . . . . . . . . . . . . . . . . . . 3-24
TPA005D12 Class-D EVM Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
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Chapter 1
Introduction
This chapter provides an overview of the Texas Instruments (TI )TPA005D12
class-D stereo audio power amplifier evaluation module (SLOP246). It
includes a list of EVM features, a brief description of the module illustrated with
a pictorial diagram, and a list of EVM specifications.
Topic
Page
1.1 Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2
1.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–3
1.3 TPA005D12 Class-D EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . 1–4
1-1
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Feature Highlights
1.1 Feature Highlights
The TI TPA005D12 class-D stereo audio power amplifier evaluation module
and the TI plug-n-play audio amplifier evaluation platform include the following
features:
TPA005D12 Class-D Stereo Audio Power Amplifier Evaluation Module
Internal depop circuitry to greatly reduce turn-on transients in outputs
Dual channel, bridge-tied load (BTL) only operation
5 V operation
2 W BTL output into 4 Ω at 5 V
Low current consumption in shutdown/mute mode (50 µA/2.5 mA)
Internal gain set to 20 dB
IC shutdown and mute control inputs — TTL logic level
High efficiency
CE tested and approved.
Quick and Easy Configuration With The TI Plug-N-Play Audio Amplifier
Evaluation Platform
Evaluation module is designed to simply plug into the platform,
automatically making all signal, control, and power connections
Platform provides flexible power options
Jumpers on the platform select power and module control options
Switches on the platform route signals
Platform provides quick and easy audio input and output connections
Platform Power Options
External 5-V – 15-V V
supply inputs
CC
External regulated V
supply input
DD
Socket for onboard 5 V/3.3 V V
voltage regulator EVM
DD
Onboard overvoltage and reverse polarity power protection
Platform Audio Input and Output Connections
Left and right RCA phono jack inputs
Miniature stereo phone jack input
Left and right RCA phono jack outputs
Left and right compression speaker terminal outputs
Miniature stereo headphone jack output
1-2
Introduction
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Description
1.2 Description
The TPA005D12 class-D stereo audio power amplifier evaluation module is a
complete, 2-Watt per channel stereo audio power amplifier. It consists of the
TI TPA005D12 class-D stereo audio power amplifier IC along with a small
numberofotherpartsmountedonacircuitboardthatmeasuresapproximately
2
inches by 2 inches (Figure 1–1 and 1–2).
Figure 1–1. The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View
TP12
L3
L4
TP11
TP9
Texas
Instruments
1999
TP10
L1
C19
C18
L2
U1
C13
C14
+
TP6 TP5
TP4
+
TP7
TP3
C5
TP1
R2
R1
TP2
GND+RIN–
–LIN+GND
Figure 1–2. The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Bottom View
C25
C24
C23
C22
C21
C20
C17
C15
C16
C9
C12
C10
C6
C11
C8
C7
1-3
Introduction
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TPA005D12 Class-D EVM Specifications
Single in-line header pins extend from the underside of the module circuit
board to allow the EVM to either be plugged into the TI plug-n-play audio
Amplifier evaluation Platform, or to be wired directly into existing circuits and
equipment when used stand-alone.
TheplatformhasroomforasingleTPA005D12class-Devaluationmoduleand
is a convenient vehicle for demonstrating TI’s audio power amplifier and
related evaluation modules. The EVM simply plugs into the platform, which
automatically provides power to the modules, interconnects them correctly,
andconnectsthemtoaversatilearrayofstandardaudioinputandoutputjacks
and connectors. Easy-to-use configuration controls allow the platform and
EVMs to quickly model many possible end-equipment configurations.
There is nothing to build, nothing to solder, and nothing but the speakers
included with the platform to hook up.
1.3 TPA005D12 Class-D EVM Specifications
All measurements made with V = 5 V and R = 4 Ω, unless otherwise noted.
DD
L
1.3.1 Maximum
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 V to 5.5 V
DD
Supply current, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 A
DD
Continuous output power per channel, BTL, P . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 W
O
Audio input voltage, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 mVrms
I
1.3.2 Typical
Supply current, no input, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 mA
DD
Supply current, EVM mute, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 mA
DD
Supply current, EVM shutdown, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 µA
DD
Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 dB
Crosstalk, P = 2 W @ 1 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –60 dB
O
Total harmonic distortion + noise, P = 1 W @ 1 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1 %
O
1-4
Introduction
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Chapter 2
Quick Start
Follow the steps in this chapter to quickly prepare the TPA005D12 class-D
stereo audio amplifier EVM for use. Using the TPA005D12 class-D EVM with
the TI plug-n-play audio amplifier evaluation platform is a quick and easy way
to connect power, signal and control inputs, and signal outputs to the EVM
using standard connectors. However, the audio amplifier evaluation module
can be used stand-alone by making connections directly to the module pins,
and it can be wired directly into existing circuits or equipment.
The platform switch and jumper settings shown in Table 2–1 are typical for the
TPA005D12 class-D EVM. There are no jumpers or switches to set on
the TPA005D12 class-D EVM board, itself.
Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the
TPA005D12 Class-D EVM
POWER TYPE (Note 2)
JP4
JP5
JP6
JP7
JP8
S1
S2 (Note3)
S3
VDD (J6)
X
ON
Mute
X
Lo
X
OFF
U5
Notes: 1) ON = Jumper installed, OFF = Jumper NOT Installed, X = Don’t care
2) UnregulatedandbatterysourcesmusthaveavoltageregulatorEVM(SLVP097)installedinplatformsocketU6(see
table 3–4, Section 3.5.5 for these options).
3) Set to ON when tone control board SLOP109 is installed in U1.
Topic
Page
2.1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–2
2.2 Quick Start List for Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–3
2.3 Quick Start List for Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2–5
2-1
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Precautions
2.1 Precautions
Power Supply Input Polarity and Maximum Voltage
Always ensure that the polarity and voltage of the external power
connected to V
power input connector J1, J2, and/or V
power
CC
DD
input connector J6 are correct. Overvoltage or reverse-polarity
power applied to these terminals can open onboard soldered-in
fuses and cause other damage to the platform, installed evaluation
modules, and/or the power source.
Inserting or Removing EVM Boards
Do not insert or remove EVM boards with power applied — damage
to the EVM board, the platform, or both may result.
Figure 2–1. Quick Start Platform Map
1
8
ICC
JP4
C1+
F1
VR1
DC
Power
In/Out
7
12
Power
Input
R2
R1
Audio
Power
Amps
Signal Conditioning
9
Audio
Input
10
14
Speaker
Output
11
Mode
Mute
Polarity
Lo
****CAUTION****
Do not insert or remove
EVM boards with power
applied
5
Hi
Stereo
Headphone
Output
Plug-N-Play Audio Amplifier
Evaluation Platform
SLOP097 Rev. C.1
R3
R4
HP Out
R5
3
13
2
4
6
2-2
Quick Start
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Quick Start List for Platform
2.2 Quick Start List for Platform
Follow these steps when using the TPA005D12 class-D EVM with the TI
plug-n-play audio amplifier evaluation platform (see the platform user’s guide,
SLOU011, for additional details). Numbered callouts for selected steps are
shown in Figure 2–1 and details appear in Chapter 3.
Platform Preparations
1) Ensure that all external power sources are set to OFF.
2) Install a TPA005D12 module in platform socket U2, taking care to align the
module pins correctly (EVM power pins engage sockets U2 and U3).
3) Set switch S2 to OFF.
4) Set switch S3 to U5.
5) Set jumper JP6 to select the Mute control input.
6) Set control signal Polarity jumper JP8 to Lo.
Table 2–2. Platform Jumper and Switch Settings for the TPA005D12
POWER TYPE (Note 2)
JP4
JP5
JP6
JP7
JP8
S1
S2 (Note 3)
S3
VDD (J6)
X
ON
Mute
X
Lo
X
OFF
U5
Notes: 1) ON = Jumper installed, OFF = Jumper NOT Installed, X = Don’t care
2) Unregulated and battery sources must have a voltage regulator EVM (SLVP097) installed in platform socket U6.
3) Set to ON when tone control board SLOP109 is installed in U1.
Power supply
7) Connect a 5-V regulated power supply (ensure power supply is set to
OFF ) to J6, taking care to observe marked polarity.
8) Set jumper JP5 for VDD power to EVMs.
Inputs and outputs
9) Ensure that the audio signal source level is set to minimum.
10) Connect the audio source to left and right RCA phono jacks J3 and J5 or
stereo miniature phone jack J4.
11) Connect 4-Ω – 8-Ω speakers to left and right RCA jacks J7 and J9 or to
stripped wire speaker connectors J8.
Power up
12) Verify correct voltage and input polarity and set the external power supply
to ON.
Platform LED2 should light indicating the presence of V , and the evaluation
DD
module(s) installed on the platform should begin operation.
13) Set switch S2 to ON if tone control board SLOP109 is installed in U1.
14) Adjust the signal source level as needed.
2-3
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Quick Start List for Stand-Alone
2.3 Quick Start List for Stand-Alone
Follow these steps to use the TPA005D12 class-D EVM stand-alone or to
connect it into existing circuits or equipment. Connections to the TPA005D12
module header pins can be made via individual sockets, wire-wrapping, or
solderingtothepins, eitheronthetoporthebottomofthemodulecircuitboard.
Power supply
1) Ensure that all external power sources are set to OFF.
2) Connect an external regulated power supply set to 5 V to the module VDD,
VDD2, and GND pins taking care to observe marked polarity. It is only
necessary to use the ground pins adjacent to the module power pins.
Inputs and outputs
3) Ensure that audio signal source level adjustments are set to minimum.
4) Connect the audio source to the module RIN+/RIN– and LIN+/LIN– pins
for class-D operation, taking care to observe marked polarity. For
single-ended input, the negative input pins (RIN– and LIN–) should be
connected to the ground of the audio signal source.
5) Connect a control signal to the module Mute pin, if necessary. The control
signal should be high (2 V to 5 V or left floating) for normal operation, or
low (tied to ground) to mute the output.
6) Connect a control signal to the module SD pin, if necessary. The control
signal should be high (2 V to 5 V or left floating) for normal operation, or
low (tied to ground) to shut down the TPA005D12 amplifier IC on the EVM.
NotethatthecontrolsignalsappliedtotheEVMmuteandSDinputsmusthave
sufficient current capability to overcome the 100-kΩ pullup resistor on each
input. Miniature pushbutton switches on the EVM allow manual shutdown (S2)
and manual muting (S1) of the amplifier.
7) Connect a 4-Ω – 8-Ω speaker to the module Rout+/Rout– pins and
another speaker to the Lout+/Lout– pins, taking care to observe marked
polarity.
Power up
8) Verify correct voltage and input polarity and set the external power supply
to ON.
The EVM should begin operation.
9) Adjust the signal source level as needed.
2-4
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Chapter 3
Details
This chapter provides details on the TPA005D12 IC, the evaluation module,
and the steps in the Quick-Start list, a discussion of class-D amplifiers,
additional application information, a parts list for the TPA005D12 class-D
evaluation module, module performance graphs, and module PCB layer
illustrations.
Topic
Page
3.1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
3.2 The TPA005D12 Class-D Audio Power Amplifier EVM . . . . . . . . . . . . 3-3
3.3 Class-D Amplifier Design Considerations . . . . . . . . . . . . . . . . . . . . . . 3-10
3.4 Using The TPA005D12 Class-D EVM With the P-N-P Platform . . . . 3-11
3.5 Using The TPA005D12 Class-D EVM Stand-Alone . . . . . . . . . . . . . . . 3-18
3.6 TPA005D12 Class-D EVM Performance Characteristics . . . . . . . . . . 3-20
3.7 TPA005D12 Class-D EVM Interconnects . . . . . . . . . . . . . . . . . . . . . . . . 3-24
3.8 TPA005D12 Class-D Evaluation Module Parts List . . . . . . . . . . . . . . 3-25
3.9 TPA005D12 Class-D EVM Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
3.10 TPA005D12 Class-D EVM PCB Layers . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
3-1
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Precautions
3.1 Precautions
Power Supply Input Polarity and Maximum Voltage
Always ensure that the polarity and voltage of the external power
connected to V
power input connector J1, J2, and/or V
power
CC
DD
input connector J6 are correct. Overvoltage or reverse-polarity
power applied to these terminals can open onboard soldered-in
fuses and cause other damage to the platform, installed evaluation
modules, and/or the power source.
Inserting or Removing EVM Boards
Do not insert or remove EVM boards with power applied — damage
to the EVM board, the platform, or both may result.
Figure 3–1. The TI Plug-N-Play Audio Amplifier Evaluation Platform
ICC
JP4
C1+
F1
VR1
DC
Power
In/Out
Power
Input
R2
R1
Audio
Power
Amps
Signal Conditioning
Audio
Input
Speaker
Output
Mode
Mute
Polarity
Lo
****CAUTION****
Do not insert or remove
EVM boards with power
applied
Hi
Stereo
Headphone
Output
Plug-N-Play Audio Amplifier
Evaluation Platform
SLOP097 Rev. C.1
R3
R4
HP Out
R5
3-2
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
3.2 The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
The TPA005D12 class-D stereo audio power amplifier evaluation module is
powered by a TPA005D12 class-D stereo power amplifier integrated circuit.
The EVM is capable of delivering greater than 2 W of continuous average
power per channel into 4-Ω loads at less than 0.6% THD+N over a 20-Hz to
20-kHz frequency range from a 5-V supply.
The TPA005D12 amplifier IC operates in the bridge-tied load (BTL) mode for
maximum efficiency during class-D operation. The high IC switching
frequency reduces the size of the output filter to three small capacitors and two
small inductors per class-D channel. The evaluation module includes onboard
pushbutton switches for manual muting and shutdown, and input pins for logic
control of mode, mute, and shutdown.
The module can be used with the TI plug-n-play audio amplifier evaluation
platform (Figure 3–1) or wired directly into circuits or equipment. The module
has single in-line header connector pins mounted to the underside of the
board. These pins allow the module to be plugged into the platform, which
automatically makes all the signal input and output, power, and control
connections to the module.
The module connection pins are on 0.1-inch centers to allow easy use with
standard perf board and plug board-based prototyping systems. Or, the EVM
can be wired directly into existing circuits and equipment when used
stand-alone.
The module appears in Figure 3–2 (top side) and Figure 3–3 (bottom side),
and its schematic is shown in Figure 3–4. Note that several components are
mounted on the bottom side of the EVM PCB.
3-3
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
Figure 3–2. The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View
TP12
L3
L4
TP11
TP9
Texas
Instruments
1999
TP10
L1
C19
C18
L2
U1
C13
C14
+
TP6 TP5
TP4
+
TP7
TP3
C5
TP1
R2
R1
TP2
GND+RIN–
–LIN+GND
Figure 3–3. The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Bottom View
C25
C24
C23
C22
C21
C20
C17
C15
C16
C9
C12
C10
C6
C11
C8
C7
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
Figure 3–4. TPA005D12 Class-D EVM Schematic Diagram
VDD
R2
100k
R1
100k
+5V
+5V
VDD
VDD2
SD
S2
SD
TP2
TP3
TPA005D12
1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
Mute
SHUTDOWN
COSC
AGND
C5
470pF
2
3
S1
Mute
MUTE
AGND
AGND
C1
1µF C4
470pF C7
1µF
C3 1µF
C2 1µF
C6
4
LINN
RINN
LIN–
LIN+
RIN–
RIN+
5
LINP
RINP
470pF
6
LCOMP
AGND
VDD
RCOMP
FAULT_0
FAULT_1
RPVDD
ROUTP
ROUTP
PGND
7
C13
C9
C10
1µF
C11
1µF
C12
C14
TP2
TP3
C8 1µF
8
10µF
10µF
9
VDD
LPVDD
LOUTP
LOUTP
PGND
PGND
LOUTN
LOUTN
LPVDD
NC
VDD2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
LOUT+
ROUT+
L1
15µH
L2
15µH
C20
C23
0.22µF
0.22µF
C21
C24
C25
1µF
1µF
PGND
C22
0.22µF
L3
15µH
L4
15µH
ROUTN
ROUTN
RPVDD
NC
0.22µF
LOUT–
ROUT–
NC
NC
NC
NC
AGND
PVDD
VCP
V2P5
PVDD
PGND
CP4
C16
1µF
C15
1µF
C17
0.1µF
CP3
CP2
CP1
0.047µF
C18
VDD
C19 0.047µF
3.2.1 TPA005D12 Class-D Stereo Audio Amplifier IC
The TPA005D12 class-D stereo audio power amplifier integrated circuit
converts low-level audio into pulse-width-modulated (PWM) signals, which
result in an audio output with a 20-dB increase in amplitude. The IC features
high-current DMOS output transistors and internal feedback that provides
excellent performance without the need for external components (beyond
input isolation and output filtering).
A full range of protection features are built into the TPA005D12 amplifier IC to
increase device reliability: thermal, overcurrent, and undervoltage shutdown,
with status terminals that report any error conditions encountered.
The device is provided in a very small 48-pin thermally-enhanced PowerPAD
TSSOP surface-mount package (DCA) and consumes only 1 µA in the
shutdown mode, making the TPA005D12 an excellent choice for portable
battery-powered applications.
3-5
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
3.2.2 Overview of Class-D Audio Amplifiers
Class-D audio amplifiers are very similar in operation to switch-mode power
suppliesinthatbothcompareaninputsignalwithareferencetocreateanerror
voltage that controls a pulse-width modulator (PWM) circuit. The PWM circuit
thenproducesanoutputsignalatconstantfrequencyandwithadutycyclethat
varies according to the input signal. A block diagram of the major components
that make up the amplifier is shown in Figure 3–5.
Figure 3–5. Class-D Functional Diagram
Audio
Analog
Source
V
V
CONTROL
ERROR
PWM
Control
Comparator
H-Bridge
V
IN
V
OUT
V
RAMP
Ramp
Generator
Load
LPF
The audio input signal (V ) is applied to a very fast comparator along with a
IN
ramp signal (V
) created by the ramp generator. Each time the triangle
RAMP
wave from the ramp generator crosses the audio input signal level, the
comparator sends an error signal (V ) to the PWM control circuit. The
ERROR
PWM control signal (V
) then regulates the duty cycle of the
CONTROL
high-current DMOS power transistors of the H-bridge, providing the output
signal (V ).
OUT
These transistors operate in either the cutoff or saturated regions, rather than
the linear region, which is where class AB amplifiers operate. This reduces
switching and conduction losses, reducing the power dissipated by the power
transistors and allowing more power to be delivered to the load. An
inductor-capacitor (LC) low-pass filter (LPF) then removes the high frequency
switching component from V
, leaving an amplified version of the original
OUT
input signal. Examples of these waveforms are shown in Figure 3–6.
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
Figure 3–6. Class-D Input and Output Waveforms
V
IN
V
RAMP
V
DD
V
OUT
0 V
The V
signal must be at a much higher frequency than the highest
RAMP
frequency component of V to obtain an accurate representation at the
IN
low-pass filter output and allow greater attenuation of the switching
component of V
. The TPA005D12 class-D EVM uses a 250 kHz V
OUT
RAMP
signal to sample V . This frequency is more than ten times higher than the
IN
highest frequency component of the 20 Hz to 20 kHz range of the audio input,
providing excellent output resolution and easy filtering by the LPF.
3.2.3 Bridge-Tied Load (BTL) Operation
The DMOS output transistors of the TPA005D12 class-D amplifier IC are
arranged in an H-bridge configuration to allow BTL operation. In the BTL
output mode, each half of the H-bridge operates 180° out of phase from the
other. The load, in this case, a speaker, is then connected between the two
halves, and is not connected directly to ground. The load is, in a sense,
floating.
BTL operation has two main advantages over single-ended operation. First,
it eliminates the need for a bulky output coupling capacitor to block any dc
offset voltage that may be present (which reduces the speaker response and
may damage the speaker). And second, it quadruples the output power that
can be delivered to the load. For more information, see the TPA005D12
amplifier IC data sheet, TI Literature Number SLOS240.
To operate in the BTL output mode, the EVM output signal from Rout+/Lout+
must go through the speaker load and be returned directly
toRout–/Lout–, andNOTtosystemground. ThisrequiresthattheRout–/Lout–
lines be isolated not only from system ground, but also from each other and
the out– lines of any other amplifiers in the system. The plug-n-play platform
provides such isolated output lines, connecting the EVM output pins directly
to left and right speaker connectors.
3-7
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
3.2.4 Class-D Differential Inputs
The TPA005D12 EVM line inputs allow the use of a single-ended or differential
audio source. The differential input stage of the amplifier cancels any noise
that appears on both input lines of a channel. To use the EVM with a differential
source, connect the positive lead of the audio source to the RIN+/LIN+ inputs
and the negative lead to the RIN–/LIN– inputs. To use the EVM with a
single-ended source, connect the positive lead of the audio source to the
RIN+/LIN+ inputs and the ground lead to the RIN–/LIN– inputs. This ac
grounds the input capacitors on the negative terminals and balances the input
impedance of the class-D amplifier’s positive and negative input terminals,
preventing voltage differences that result in popping in the speakers.
3.2.5 Control and Indicator Circuits
Three main control circuits are provided with the TPA005D12. The mute circuit
grounds the output of the active amplifier, and the shutdown circuit places the
entire device into a power-saving sleep mode to minimize current
consumption. Each of these inputs is TTL compatible: less than 0.8 V applied
to these pins is considered a logic low, and any voltage greater than 2 V is
considered a logic high.
Two indicator pins are also provided for feedback when an under-voltage,
over-current, or thermal fault exists. Module pins are provided for easy
connection of off-board control and monitoring. There are two active low fault
indicator pins on the TPA005D12 amplifier IC (IC pins 40 and 41) that provide
feedback when a fault condition exists. Signals on these pins provide the
status of the class-D amplifier: operational, over-current, thermal fault, and
under-voltage lockout. Table 3–1 lists the possible output conditions of these
pins and a description of the fault indicated.
Table 3–1.TPA005D12 Class-D EVM Fault Indicator Table
FAULT 0
(TP 2)
FAULT 1
(TP 3)
DESCRIPTION
1
1
1
0
No fault. — The device is operating normally.
Charge pump under-voltage lockout (VCP-UV) fault — the charge pump voltage is < (PVDD + 6V).
All low-side transistors are turned on, shorting the load to ground. Normal operation resumes when
the charge pump voltage is restored (not a latched fault), however the Fault indication remains
active until cleared by cycling MUTE, SHUTDOWN, or the power supply.
0
0
1
0
Over-current fault — the output current limit has been exceeded. All output transistors are switched
off, causing the load to see a high impedance state. This is a latched fault and is cleared by cycling
MUTE, SHUTDOWN, or the power supply.
Thermal fault — the internal junction temperature has exceeded 125°C. All of the low-side
transistors are turned on, shorting the load to ground. Once the junction temperature drops by 20°C
and is below 125°C, normal operation resumes (not a latched fault). The Fault indication remains
active until cleared by cycling MUTE, SHUTDOWN, or the power supply.
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The TPA005D12 Class-D Audio Power Amplifier Evaluation Module
3.2.6 TPA005D12 Class-D EVM Test Points
Test points have been included on the TPA005D12 class-D EVM to facilitate
user analysis of device performance and design adjustments. Table 3–2 lists
each test point and its corresponding function.
Table 3–2.TPA005D12 Class-D EVM Test Points
TEST IC PIN or EVM
FUNCTION
POINT
FUNCTION
COSC
FAULT_0
FAULT_1
N/A
1
2
Ramp generation capacitor input and output
LSB for logic-level fault output signal, open drain
MSB for logic-level fault output signal, open drain
Probe ground connections
3
4
5
LOUTP
VCP
Class-D left channel positive output of the H-bridge
Charge pump storage capacitor
6
7
ROUTP
VDD
Class-D right channel positive output of the H-bridge
Probe VDD power input connections
8
9
VDD2
Probe VDD2 power input connections
10
11
12
LOUTN
ROUTN
N/A
Class-D left channel negative output of the H-bridge
Class-D right channel negative output of the H-bridge
Probe ground connections
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Class-D Amplifier Design Considerations
3.3 Class-D Amplifier Design Considerations
Detailed information for proper design and implementation of TI class-D audio
power amplifiers appears in the application report Design Considerations for
Class-D Audio Power Amplifiers, TI Literature Number SLOA031, on the TI
information, general equations, and component selection criteria for the topics
listed below. General layout considerations are also included in the report.
Class-D amplifier circuits (input, output, charge pump, and switching)
Control and indicator circuits
Power supply decoupling
The application report Reducing and Eliminating the Class-D Output Filter,
SLOA023, is also available from the website, and provides information to help
determine what type of output filter, if any, may be necessary.
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Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
3.4 Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
The TPA005D12 class-D stereo audio amplifier evaluation module was
designed to be used with the TI plug-n-play audio amplifier evaluation
platform. It simply plugs into socket U2 and U3.
The following paragraphs provide additional details for using the TPA005D12
class-D EVM with the platform.
3.4.1 Installing and Removing EVM Boards
TI plug-n-play evaluation modules use single-in-line header pins installed on
the underside of the module circuit board to plug into sockets on the platform.
The EVM pins and the platform sockets are keyed such that only the correct
type of EVM can be installed in a particular socket, and then only with the
proper orientation.
Evaluation modules are easily removed from the platform by simply prying
them up and lifting them out of their sockets. Care must be taken, however, to
prevent bending the pins.
3.4.1.1 EVM Insertion
1) Remove all power from the evaluation platform.
2) Locate sockets U2 and U3 on the platform.
3) Orient the module correctly.
4) Carefully align the pins of the module with the socket pin receptacles.
5) Gently press the module into place.
6) Check to be sure that all pins are seated properly and that none are bent
over.
3.4.1.2 EVM Removal
1) Remove all power from the evaluation platform.
2) Using an appropriate tool as a lever, gently pry up one side of the module
a small amount.
3) Change to the opposite side of the module and use the tool to pry that side
up a small amount.
4) Alternate between sides, prying the module up a little more each time to
avoid bending the pins, until it comes loose from the socket.
5) Lift the EVM off of the platform.
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Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
3.4.2 Module Switches
The TPA005D12 class-D stereo audio amplifier evaluation module is
equipped with two pushbutton switches that allow the module shutdown and
mute functions to be manually activated.
3.4.2.1 S1 — Shutdown
To have the module amplifier IC enter the shutdown mode, press the
Shutdown switch (S2) on the module. S2 connects the amplifier IC
SHUTDOWN pin to ground, forcing it into a low-power state. This function can
be controlled by an external control input to the SD module pin.
The shutdown mode reduces the amplifier IC current consumption to
approximately 1 µA compared to approximately 2.5 mA in the mute mode. The
EVM shutdown current is based on V
R2, and capacitor leakage currents,
DD,
but will typically be 50 µA ±5% for V = 5 V. The plug-n-play platform typically
DD
draws 23 mA of current.
3.4.2.2 S2 — Mute Switch
Pushbutton switch S1 on the TPA005D12 class-D EVM allows manual muting
of the amplifier IC. S1 connects the amplifier IC MUTE pin to ground, muting
the output. The EVM Mute control input pin also allows external control of this
function.
In the mute mode, the amplifier IC lowside output transistors are turned on,
shorting the load to ground. This reduces the EVM current to 2.5 mA.
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Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
3.4.3 Signal Routing
Signal flow on the platform is controlled by two signal routing switches, as
shown in Figure 3–7.
Figure 3–7. Platform Signal Routing and Outputs
Off
+
–
R
R
L
R
U2/U3
TPA005D12
Amplifier EVM
J7, J8, J9
Speaker
Outputs
U1
Signal
Conditioning
Audio
Input
S2
–
+
L
L
On
U2–U4
R
+
–
R
U5
Stereo
Headphone
Amplifier
J10
Headphone
Output
GND
S3
L
–
+
L
U5
3.4.3.1 Signal Conditioning
The audio signal from input jacks can be applied to the signal conditioning
socket (U1) if an EVM is installed there, or socket U1 can be bypassed and the
audio input signal applied directly to the inputs of the TPA005D12 class-D
EVM.
Platform switch S2 selects signal conditioning or bypasses it.
3.4.3.2 Headphone Output Jack
Switch S3 is the source select for the stereo headphone output jack, J10. The
headphone jack is capacitively coupled (via 470 µF electrolytics) and can
output either the signal from the headphone amplifier in socket U5, or the
signal from the power amplifier installed in socket U2, as determined by the
setting of headphone source select switch S3.
The platform headphone output jack (J10) is not used in conjunction with
the TPA005D12 class-D EVM. Switch S3 should be set to the U5 position
when the TPA005D12 class-D EVM is installed on the platform.
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Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
3.4.4 Shutdown
The TPA005D12 class-D EVM is equipped with a shutdown control input pin.
When this input is tied to GND, the TPA005D12 amplifier IC on the module
enters the shutdown mode and dissipates very little power. When the EVM
control input is tied to V
or allowed to float, amplifier operation resumes.
DD
In typical applications, as often found in notebook computers and other
portable audio products, the internal speakers mute when headphones are
plugged into the headphone jack, or internal speakers mute when external
speakers are connected. In applications using separate speaker and
headphone amplifiers, the one not being used can be muted to conserve
power.
The TPA005D12 EVM shutdown control pin connects to the platform Mute line
of JP6 when the EVM is inserted in the plug-n-play platform. When JP6 is set
to Mute and JP8 is set to Lo, the class-D EVM will operate normally until a
headphone plug is inserted into platform jack J10 and the class-D amplifier is
placed into shutdown. Once the jack is removed from J10, the class-D EVM
again becomes active. Note that when JP6 is set to mute and the class-D EVM
shutdown pin is activated, the platform current increases by approximately 20
mA. This current is set by the connection of the 240-Ω platform resistor (R3)
to ground through the EVM shutdown switch.
3.4.4.1 Headphone Jack Control Signals
The platform headphone output jack (J10) contains an internal switch that
changesthestateofapairofcontrollineswhenaplugisinserted(Figure3–8).
Each control line is pulled down by a 1-kΩ resistor to ground (R4 and R5). The
switch in the headphone jack pulls one line or the other up to V
through a
DD
240-Ω resistor (R3) depending on whether a plug is inserted in J10 or not.
Figure 3–8. Mute/Mode and Polarity Control
V
DD
R3
240 Ω
Polarity
JP8
JP6
Mode
Mute
Lo
U2
Power
Amplifier
J10
Headphone
Jack
Hi
R4
1 kΩ
R5
1 kΩ
SPK
(U2–U4)
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Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform
3.4.4.2 Mute/Mode Select (JP6)
A 3-pin jumper header (JP6) on the platform, functioning as an SPDT switch,
routes the control signal from the headphone jack to either the mute control
input pin or the mode control input pin of the evaluation module.
Set jumper JP6 to MODE when a separate headphone amplifier is
NOT installed in U5.
Set jumper JP6 to MUTE when a separate headphone amplifier IS
installed in U5. This will cause the TPA005D12 class-D EVM to shut
down when a plug is inserted into platform headphone jack J10.
3.4.4.3 Mute/Mode Polarity Select (JP8)
A second 3-pin jumper header (JP8) on the platform selects the control signal
polarity by connecting either the active-high or the active-low line from the
headphone jack to jumper JP6.
Set jumper JP8 to Lo for normal class-D operation when a separate
headphone amplifier IS installed in U5.
3-15
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Power Requirements
3.4.5 Power Requirements
The TPA005D12 class-D stereo audio power amplifier evaluation module is
designed to operate from a supply voltage between 4.5 V and 5.5 V. For best
performance (highest output power with lowest distortion), the module should
be operated at 5 V.
The TI plug-n-play audio amplifier evaluation platform provides several
options for powering the TPA005D12 class-D EVM. Table 3–3 shows the
platform jumper and switch settings for each power source option (see the
User’s Guide for the TI plug-n-play audio amplifier platform, TI Literature
Number SLOU011 for more information). The TPA005D12 class-D EVM
requires no setup for power source selection.
Table 3–3.Platform Jumper and Switch Settings for the TPA005D12 EVM Power Inputs
POWER TYPE (Note 2)
VCC (J1)
JP1
ON
JP2
OFF
ON
JP3
OFF
OFF
ON
JP4
ON
ON
ON
X
JP5
ON
ON
ON
ON
JP6
JP7
X
JP8
Hi
S1
ON
ON
ON
ON
S2
S3
U5
U5
U5
U5
Mode
Mode
Mode
Mode
Note 3
Note 3
Note 3
Note 3
AC/DC (J2)
OFF
OFF
OFF
X
Hi
Battery (B1)
OFF
OFF
X
Hi
VDD (J6)
OFF
X
Hi
Notes: 1) ON = Jumper installed, OFF = Jumper NOT Installed, X = Don’t care
2) Unregulated and battery sources must have a voltage regulator EVM (SLVP097) installed in platform socket U6.
3) Set to ON when Tone Control Board SLOP109 is installed in U1, otherwise set to OFF..
Although the TPA005D12 amplifier IC draws approximately 0.7 A per channel
from the power supply during continuous full power output, peak current draw
can be as high as 1.15 A per channel. Any power supply connected to the
platform should be capable of providing 2.3 A to avoid clipping of the output
signal during voltage peaks. Current consumption driving speakers at normal
listening levels is typically 0.1 A or less.
A V
supply of 5 V is required if a signal processing EVM is installed in
DD
platform socket U1 or a separate headphone amplifier EVM is installed in U5.
V
can either be applied to the platform V power input terminals (J6) or a
DD
DD
voltage regulator (SLVP097 or equiv.) can be installed in platform socket U6
to provide V from the platform V supply.
DD
CC
The platform is equipped with overvoltage and reverse-polarity supply voltage
input protection in the form of fused crowbar circuits.
V
voltage applied to platform screw terminals J6 MUST NOT exceed
DD
the absolute maximum rating for the TPA005D12 amplifier IC installed on
the evaluation module (5.5 V) or damage to the IC may result. In no case
shouldV voltageoftheincorrectpolarityorinexcessof6.0Vbeapplied
DD
to screw terminals J6 of the platform, or the power protection circuit on the
V
line will trip.
DD
V
voltage applied to the platform MUST NOT exceed the maximum
CC
voltage input specified for the voltage regulator module installed in socket
U6 (12 V for the SLVP097), or damage to the voltage regulator module
may result. In no case should V
voltage applied to the platform exceed
CC
15 V, or the overvoltage protection circuit on the V
bus will trip.
CC
3-16
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Inputs and Outputs
3.4.6 Inputs and Outputs
The TI plug-n-play audio amplifier evaluation platform is equipped with several
standard conectors for audio inputs and outputs.
3.4.6.1 Inputs
In most cases, audio signals enter the platform through either a pair of RCA
phono jacks (J3 and J5) or a miniature (1/8″) stereo phone jack (J4). Certain
signal conditioning and amplifier EVMs, however, may have additional signal
input connectors mounted on the module circuit board.
The platform audio signal input jacks (J3, J4, and J5) are of the closed-circuit
type, grounding the signal input lines when no plugs are inserted.
3.4.6.2 Outputs
Amplified audio output signals leave the platform through left and right RCA
phono jacks (J7 and J9), left and right pairs of compression connectors for
stripped speaker wires (J8), and optionally, through a miniature (1/8″) stereo
phone jack (J10), for headphones.
The audio output lines from the power amplifiers are separate all the way to
the edge of the platform (output jacks J7, J8, and J9)—the OUT– lines from
the power amplifier sockets are not tied to each other or to platform ground.
This allows the TPA005D12 class-D power amplifier EVM to operate in the
highly-efficient bridge-tied load configuration when driving speakers.
The headphone jack (J10) is capacitively coupled to source select switch S3,
which connects J10 to the output lines of either the headphone amplifier
socket or the power amplifier sockets (Figure 3–9).
Figure 3–9. Typical Headphone Plug
Left
Right
GND
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Using The TPA005D12 Class-D EVM Stand-Alone
3.5 Using The TPA005D12 Class-D EVM Stand-Alone
Using the TPA005D12 class-D stereo audio power amplifier evaluation
module stand-alone is much the same as using it with the platform. The same
4.5-V to 5.5-V power supply range and the isolated out+ and out– lines for BTL
operation (Section 3.2.3) requirements exist. Figure 3–10 shows the
connections that are required for operation (with the exception of the fault
monitor circuit, which is optional). The discussion in this section is in reference
to this figure unless otherwise noted.
Figure 3–10. TPA005D12 Class-D EVM Stand-Alone Connections for Stereo BTL Output
LED 1
5 V
R
5 V
R
LED 0
Fault
SLOP246 TPA005D12 EVM Board
Monitor
VDD2
GND
Rout+
Rout–
Mute
Right
Audio
Inputs
(Right)
C4
C1
Mute
SD
S2
Mute
S1
Shutdown
SD
C3
Audio
Inputs
(Left)
Lout–
C2
Left
TP8
GND
Lout+
VDD
5 V
3.5.1 Power Connections
Power must be connected to both the VDD and VDD2 module pins. Power
supply ground can be connected to any module ground pin, although best
results are achieved if power supply grounds are connected to the pins
adjacent to the VDD and VDD2 module pins. The ground and power wires
should be twisted to reduce inductance and noise pickup if they are long.
3-18
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Using The TPA005D12 Class-D EVM Stand-Alone
3.5.2 Input Connections
The class-D amplifier input signals can be connected in either of two ways:
differential or single-ended. For differential operation, connect the two lines
from the signal source to the positive and negative inputs of each channel
(RIN+/RIN– and LIN+/LIN– module pins). For single-ended operation, the
input signal lines should be connected to the RIN+ and LIN+ module pins and
the signal source ground wires should be connected to the RIN– and LIN–
module pins.
For best results, the ground of the signal source should be connected to the
GND pins at the EVM inputs to provide a return path for the current. The input
signal and ground wires should be twisted to reduce inductance and noise
pickup if the lead lengths are long and the cable is not shielded.
3.5.3 Output Connections
The right speaker should be connected between the Rout+ and the Rout–
module pins, and the left speaker should be connected between the Lout+ and
the Lout– module pins to comply with the isolated output requirements for BTL
operation.
3.5.4 Controls and Indicators
The mute and shutdown functions may be controlled externally via the module
mute and SD pins. An active-low input mutes the selected amplifier or shuts
down the device. A signal of 2 V or higher, or a float condition, allows normal
operation.
Note that the mute and shutdown signals applied to the EVM control input pins
must be able to supply enough current to overcome the pullup resistor on the
module (100 kΩ).
The fault indicator circuit can be monitored by attaching a pullup resistor to the
open-drain outputs of FAULT0 (TP2) and FAULT1 (TP3). The voltage should
not exceed 5 V and the current must be limited to less than 1 mA. A fault table
is shown in Section 3.2.5 and the device data sheet.
3-19
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TPA005D12 Class-D EVM Performance Characteristics
3.6 TPA005D12 Class-D EVM Performance Characteristics
The TPA005D12 class-D stereo audio power amplifier EVM was tested using
an Audio Precision System II, model 2322, a 5-V regulated dc power supply,
and the TI PNP audio power amplifier evaluation platform set up as described
in Chapter 2. Results were obtained with 4-Ω and 8-Ω speaker loads. The
results are shown in Figures 3–11 through 3–17.
The frequency response shown in Figure 3–17 is a relatively flat 20 dB over
the 20 Hz to 100 kHz frequency range. The lower and upper frequency corners
can be adjusted to extend the frequency response.
Figure 3–11. Class-D Amplifier Frequency Response at 4 Ω
VOLTAGE AMPLIFICATION
vs
FREQUENCY
22.5
20
17.5
15
12.5
10
7.5
5
2.5
0
V
R
= 5 V
DD
= 4 Ω
L
–2.5
–5
TA = 25° C
10
100
1k
10k
100k
f – Frequency – Hz
Total harmonic distortion plus noise (THD+N) versus output power and
frequency is shown in Figures 3–12 through 3–15 below. Figures 3–12 and
3–13 show power sweeps at a fixed frequency of 1 kHz. Switching and input
noise begins to dominate at low power, while the distortion at the mid to upper
power levels is a function of the class-D amplifier and the inductor. The lower
frequency noise may be improved by either increasing the order of the filter or
byincreasingtheamplifierswitchingfrequency, whichwillfurtherattenuatethe
switching noise in the audio band.
Midrange distortion is a combination of the switching noise of the output power
transistors in the IC and the magnetic field created by the inductors. This
distortionisminimizedbygoodseparationoftheoutputfilterinductorsforeach
channel and through good EMI-reduction layout techniques.
3-20
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TPA005D12 Class-D EVM Performance Characteristics
Figure 3–12. Class-D Amplifier Distortion versus Output Power at 4 Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
1
V
R
= 5 V
DD
= 4 Ω
L
TA = 25° C
1 kHz
0.1
0.02
0.01
0.1
– Output Power – W
1
2
P
O
Figure 3–13. Class-D Amplifier Distortion versus Output Power at 8 Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
1
V
R
= 5 V
DD
= 8 Ω
L
TA = 25° C
1 kHz
0.1
0.02
0.01
0.1
1
2
P
O
– Output Power – W
3-21
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TPA005D12 Class-D EVM Performance Characteristics
Figures 3–14 and 3–15 show a frequency sweep for a 1-W output. The lower
frequency distortion of the graphs is dominated by noise, while the distortion
at higher frequencies is due primarily to the fast-changing duty cycle of the
PWM output.
Figure 3–14. Class-D Amplifier Distortion versus Frequency at 1 W Into 4 Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
1
V
R
= 5 V
= 4 Ω
= 1 W
DD
L
P
O
TA = 25° C
0.1
0.02
20
100
1k
10k 20k
f – Frequency – Hz
Figure 3–15. Class-D Amplifier Distortion versus Frequency at 1 W Into 8 Ω
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
1
V
R
= 5 V
= 8 Ω
= 1 W
DD
L
P
O
TA = 25° C
0.1
0.02
20
100
1k
10k 20k
f – Frequency – Hz
3-22
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TPA005D12 Class-D EVM Performance Characteristics
EVM crosstalk is shown in Figures 3–16 and 3–17. The frequency is swept
from 20 Hz to 20 kHz for a constant 2-W output. Several factors affect
crosstalk, such as component selection (especially the inductor), filter layout,
grounding, and power supply decoupling.
Figure 3–16. Class-D Amplifier Crosstalk versus Frequency at 2 W Into 4 Ω
CROSSTALK
vs
FREQUENCY
0
V
R
= 5 V
= 4 Ω
= 2 W
DD
L
–10
–20
P
O
TA = 25° C
–30
–40
–50
–60
–70
–80
–90
20
100
1k
10k 20k
f – Frequency – Hz
Figure 3–17. Class-D Amplifier Crosstalk versus Frequency at 2 W Into 8 Ω
CROSSTALK
vs
FREQUENCY
0
V
R
= 5 V
= 8 Ω
= 1 W
DD
L
–10
–20
P
O
TA = 25° C
–30
–40
–50
–60
–70
–80
–90
20
100
1k
10k 20k
f – Frequency – Hz
3-23
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TPA005D12 Class-D EVM Interconnects
3.7 TPA005D12 Class-D EVM Interconnects
Table 3–4 shows the correlation between the TPA005D12 class-D amplifier IC
pins, the EVM pins, and the plug-n-play (PNP) platform sockets.
Table 3–4.TPA005D12 Class-D EVM/Plug-N-Play Platform Interconnects
CLASS-D EVM
PLUG-N-PLAY PLATFORM
PNP SOCKET FUNCTION ON PLATFORM
IC PIN
EVM PIN
FUNCTION ON EVM
8, 9 16, 21, 28
VDD
Power for left channel, input, and
headphone circuits
VDD
Power from J1, J2, J6, or B1
40, 33
VDD2
GND
Power for right channel circuits
VDD
GND
Power from J1, J2, J6, or B1
3, 7, 12, 13, 20,
27, 36, 37, 46,
47
Analog and power ground for EVM,
all pins
Ground for platform from J1, J2,
J6, or B1
44
45
RIN+
RIN–
Class-D right channel positive input
Class-D right channel inverted input
Right In (line) Right channel input from J3 or J4
GND
Ground for platform from J1, J2,
J6, or B1
38, 39
34,35
Rout+
Rout–
Class-D right channel positive out-
put
Right Out +
Right Out –
Right channel positive output to J7
or J8
Class-D right channel inverted out-
put
Right channel negative output to
J7 or J8
5
4
LIN+
LIN–
Class-D left channel positive input
Class-D left channel inverted input
Left In (line)
GND
Left channel input from J4 or J5
Ground for platform from J1, J2,
J6, or B1
10, 11
14, 15
2
Lout+
Lout–
Mute
Class-D left channel positive output
Class-D left channel inverted output
Left Out +
Left Out –
N/C
Left channel positive output to J8
or J9
Left channel negative output to J8
or J9
Mute control external input pin: ac-
tive low — selected amplifier active
when held > 2 V
No connect
1
SD
Shutdown control external input pin:
active low — normal operation when
held > 2 V
Mute
Mute control from JP6 for use
when testing a headphone amplifi-
er in socket U5 in conjunction with
an EVM in U2/U3/U4
41
42
TP4
TP3
Fault–1: Logic level fault–1 output
signal. MSB. Open drain.
N/C
N/C
No connect
Fault–0: Logic level fault–0 output
signal. LSB. Open drain.
No connect
3-24
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TPA005D12 Class-D EVM Bill of Materials
3.8 TPA005D12 Class-D EVM Bill of Materials
The components in the bill of materials (Table 3–5) were selected for their
common values, availability, and the smallest size available to meet these
criteria.
Table 3–5.TPA005D12 Class-D EVM Bill of Materials
EVM
Qty.
Manufacturer/
Part Number
Reference
C17
Description
Size
Capacitor, Ceramic Chip, 0.1 µF, ±10%,
0805
1
Kemet
C0805C104K5RAC
50 V, X7R
C1, C2, C3, C4, Capacitor, Ceramic Chip, 1 µF, ±10%,
1206
10
TDK
C8, C10, C11,
C15, C16, C24,
C25
16 V, X7R
C3216X7R1C105K
C18, C19
C5, C6, C7
C9, C12
Capacitor, Ceramic Chip, 47 nF, ±10%,
0805
0805
1210
2
3
2
Kemet
C0805V473K5RAC
50 V, X7R
Capacitor, Ceramic Chip, 470 pF, ±5%,
50 V, C0G,
Kemet
C0805C471J5GAC
Capacitor, Ceramic Chip, 10 µF, +80%–20%,
25 V, Y5V
muRata
GRM235Y5V106Z25
C13, C14
These pads are provided for increase of bulk
capacitance as required to meet voltage ripple
and temperature operating range specifications.
0.0236” ×
0.138”
C20, C21, C22,
C23
Capacitor, Ceramic Chip, 0.22 µF, ±10%,
1206
4
4
Kemet
C1206C224K4RAC
16 V, X7R
L1, L2, L3, L4
Inductor, SMT, 15 µH, ±20%, 2.2 ADC, 47.2 mΩ 0.398” × 0.398”
@ 1 kHz, –20 to +90°C
TDK
SLF10145–150
× 0.220”
L1, L2, L3, L4
Alternate Value
Inductor, SMT, 15 µH, ±20%, 1.1 ADC, 75 mΩ
@ 1 kHz, –20 to +85°C
0.276” × 0.276”
4
TDK
SLF7032–150
× 0.126”
R1, R2
Resistor, Thick Film Chip, SMD, 100 kΩ, ±5%,
1/16 W, 150 V, –50 to 150°C, ±200 ppm/°C
0603
2
Vishay/Dale
CRCW0603104J
Headers, 0.100 in. centers, 1/2 in length
Test Point, Red
0.5”, 0.25”,
0.1”
14
10
2
Samtec
TSW–19–8–G–S
TP1, TP2, TP3,
TP5– TP11
Farnell
240–345
TP4, TP12
S1, S2
U1
Test Point, Black
Farnell
240–333
Switch, Momentary, Push Button, 12 VDC,
50 mA
0.291” × 0.138”
2
Panasonic
EVQ-PJS04K
× 0.134”
IC, Audio amplifier, class-D,
2 W, 48 pin, DCA pkg
TSSOP48
1
TI
TPA005D12DCA
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TPA005D12 Class-D EVM Schematic
3.9 TPA005D12 Class-D EVM Schematic
The following schematic depicts the TPA005D12 class-D EVM.
Note:
C13 and C14 are optional and have been provided to allow flexibility of
design.
Figure 3–18. TPA005D12 Class-D EVM Schematic Diagram
VDD
R2
100k
R1
100k
+5V
+5V
VDD
VDD2
SD
S2
SD
TP2
TP3
TPA005D12
1
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
Mute
SHUTDOWN
COSC
AGND
C5
470pF
2
3
S1
Mute
MUTE
AGND
AGND
C1
1µF C4
470pF C7
1µF
C3 1µF
C2 1µF
C6
4
LINN
RINN
LIN–
LIN+
RIN–
RIN+
5
LINP
RINP
470pF
6
LCOMP
AGND
VDD
RCOMP
FAULT_0
FAULT_1
RPVDD
ROUTP
ROUTP
PGND
7
C13
C9
C10
1µF
C11
1µF
C12
C14
TP2
TP3
C8 1µF
8
10µF
10µF
9
VDD
LPVDD
LOUTP
LOUTP
PGND
PGND
LOUTN
LOUTN
LPVDD
NC
VDD2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
LOUT+
ROUT+
L1
15µH
L2
15µH
C20
C23
0.22µF
0.22µF
C21
C24
C25
1µF
1µF
PGND
C22
0.22µF
L3
15µH
L4
15µH
ROUTN
ROUTN
RPVDD
NC
0.22µF
LOUT–
ROUT–
NC
NC
NC
NC
AGND
PVDD
VCP
V2P5
PVDD
PGND
CP4
C16
1µF
C15
1µF
C17
0.1µF
CP3
CP2
CP1
0.047µF
C18
VDD
C19 0.047µF
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TPA005D12 Class-D EVM PCB Layers
3.10 TPA005D12 Class-D EVM PCB Layers
The following illustrations depict the TPA005D12 class-D EVM PCB assembly
andlayers. Thesedrawingsarenottoscale. Gerberplotscanbeobtainedfrom
any TI Sales Office.
Figure 3–19. TPA005D12 Class-D EVM Top Assembly
Figure 3–20. TPA005D12 Class-D EVM Bottom Assembly
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TPA005D12 Class-D EVM PCB Layers
Figure 3–21. TPA005D12 Class-D EVM Top Layer
Figure 3–22. TPA005D12 Class-D EVM Second Layer
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TPA005D12 Class-D EVM PCB Layers
Figure 3–23. TPA005D12 Class-D EVM Third Layer
Figure 3–24. TPA005D12 Class-D EVM Bottom Layer
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