User’s Guide
1998
Mixed-Signal Products
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IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any
semiconductor product or service without notice, and advises its customers to obtain the latest
version of relevant information to verify, before placing orders, that the information being relied
on is current.
TIwarrantsperformanceofitssemiconductorproductsandrelatedsoftwaretothespecifications
applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality
control techniques are utilized to the extent TI deems necessary to support this warranty.
Specific testing of all parameters of each device is not necessarily performed, except those
mandated by government requirements.
Certain applications using semiconductor products may involve potential risks of death,
personal injury, or severe property or environmental damage (“Critical Applications”).
TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT APPLICATIONS, DEVICES
OR SYSTEMS OR OTHER CRITICAL APPLICATIONS.
Inclusion of TI products in such applications is understood to be fully at the risk of the customer.
Use of TI products in such applications requires the written approval of an appropriate TI officer.
Questions concerning potential risk applications should be directed to TI through a local SC
sales office.
In order to minimize risks associated with the customer’s applications, adequate design and
operating safeguards should be provided by the customer to minimize inherent or procedural
hazards.
TI assumes no liability for applications assistance, customer product design, software
performance, or infringement of patents or services described herein. Nor does TI warrant or
represent that any license, either express or implied, is granted under any patent right, copyright,
mask work right, or other intellectual property right of TI covering or relating to any combination,
machine, or process in which such semiconductor products or services might be or are used.
Copyright 1998, Texas Instruments Incorporated
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Preface
Related Documentation From Texas Instruments
TI Plug-N-Play Audio Amplifier Evaluation Platform (literature
number SLOU011) provides detailed information on the evaluation
platform and its use with TI audio evaluation modules.
TPA311 350-mW LOW-VOLTAGE AUDIO POWER AMPLIFIER
(literature number SLOS207) This is the data sheet for the TPA311
audio amplifier integrated circuit.
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.
iii
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If You Need Assistance
If You Need Assistance. . .
If you want to. . .
Do this. . .
†
Request more information about
Texas Instruments Digital Signal
Processing (DSP) products
Call the PIC hotline:
(972) 644–5580
Or send a fax to the PIC:
(972) 480–7800
Or write to:
Texas Instruments Incorporated
Product Information Center, MS 3123
P.O. Box 660246
Dallas, Texas 75266
†
Order Texas Instruments docu-
mentation
Call the PIC hotline:
(972) 644–5580
†
Ask questions about product op-
Call the PIC hotline:
eration or report suspected prob- (972) 644–5580
lems
Report mistakes in this document Send a fax to MSP Marketing Documentation
or any other TI documentation
Correction: (972) 480–3160
Or send your comments to:
Texas Instruments Incorporated
MSP Marketing Documentation, MS 8710
P.O. Box 660199
Dallas, Texas 75266–0199
†
Texas Instruments Product Information Center
iv
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Contents
1
2
3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1
1.2
1.3
Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
TPA311 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 TPA311 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3.2.1 TPA311 Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.2.2 BTL Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.2.3 Single-Ended Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.2.4 Module Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.2.5 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Using The TPA311 EVM With The Plug-N-Play Evaluation Platform . . . . . . . . . . . . . . . 3-6
3.3.1 Installing and Removing EVM Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
3.3.2 Signal Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
3.3.3 Mute/Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.3.4 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
3.3.5 Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Using The TPA311 EVM Stand-ALone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.4.1 TPA311 EVM Connected for BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
3.4.2 TPA311 EVM Connected for Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . 3-13
TPA311 Audio Amplifier Evaluation Module Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
3.3
3.4
3.5
v
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Figures
1–1
2–1
2–2
3–1
3–2
3–3
3–4
3–5
3–6
3–7
3–8
3–9
The TI TPA311 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Quick Start Platform Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Quick Start Module Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
The TI Plug-N-Play Audio Amplifier Evaluation Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
TPA311 EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
TPA311 EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
TPA311 Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Platform Signal Routing and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Mute/Mode and Polarity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Typical Headphone Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
TPA311 EVM Connected for Stereo BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
TPA311 EVM Connected for Stereo Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Tables
2–1
2–2
3–1
Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA311 . . . . . . . . . . 2-1
Platform Jumper and Switch Settings for the TPA311 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
TPA311 EVM Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
vi
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Chapter 1
Introduction
This chapter provides an overview of the Texas Instruments (TI ) TPA311
Audio Amplifier Evaluation Module (SLOP116). 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 Description
1–3
1–4
1–4
1.3 TPA311 EVM Specifications
1-1
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1-2
Introduction
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Feature Highlights
1.1 Feature Highlights
The TI TPA311 Audio Amplifier Evaluation Module and the TI Plug-N-Play
Audio Amplifier Evaluation Platform include the following features:
TPA311 Low-Voltage Audio Power Amplifier Evaluation Module
Single channel, bridge-tied load (BTL) or single-ended operation
3.3-V and 5-V operation
350 mW output power into 8 Ω at 5 V, BTL
Ultra-low current consumption in shutdown/mute mode
Internal thermal and short-circuit protection
Module gain adjustable between approximately 2 and 22
Quick and Easy Configuration with The TI Plug-N-Play Audio Amplifier
Evaluation Platform
Evaluation module is designed to simply plug into the platform, auto-
matically 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
On-board 9-V battery
External 5-V – 15-V DC V
supply inputs
CC
External regulated V
supply input
DD
Socket for on-board 5 V/3.3 V V
voltage regulator EVM
DD
On-board 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
1-3
Introduction
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Description
1.2 Description
The TPA311 Audio Power Amplifier Evaluation Module is a complete, low-
power single-channel audio power amplifier. It consists of the TI TPA311
350-mW Low-Voltage Audio Power Amplifier IC along with a small number of
other parts mounted on a circuit board that is approximately one and a quarter
inches square (Figure 1–1).
Figure 1–1. The TI TPA311 Audio Amplifier Evaluation Module
VDD GND
Shutdown
–3
C5
S1
R1
C3
009227
OUT–
GND
C2
R5
OUT+
U1
C4
Literature #
SLOP116
R3
SE\BTL*
R2
C1
IN+
R4
TPA311
GND
EVM
Single in-line header pins are mounted to the underside of the module circuit
board to allow the EVM to 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.
The platform has room for a pair of TPA311 evaluation modules and is a
convenient vehicle for demonstrating TI’s audio power amplifier and related
evaluation modules. The EVMs simply plug into the platform, which auto-
matically provides power to the modules, interconnects them correctly, and
connectsthemtoaversatilearrayofstandardaudioinputandoutputjacksand
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 TPA311 EVM Specifications
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 V to 5.5 V
DD
Supply current, I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 mA, max
DD
Continuous output power, P : 8-Ω BTL, V =5 V: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 mW
O
DD
32-Ω BTL, V =5 V: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 mW
DD
Audio input voltage, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Vpp, max
I
Minimum load impedance, R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Ω
L
1-4
Introduction
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Chapter 2
Quick Start
The steps in this chapter can be followed to quickly prepare the TPA311 audio
amplifier EVM for use. While using the TPA311 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,
the audio amplifier evaluation module can be used stand-alone by making
connections directly to the module pins, and can be wired directly into existing
circuits or equipment.
The platform switch and jumper settings shown in Table 2–1 are typical for the
TPA311 EVM and will cause the TPA311 to switch to single-ended output
mode when a plug is inserted into platform headphone jack J10.
Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA311
EVM
JP6
JP7
JP8
S2
S3
TPA311
Mode
X
Hi
Note 2
X
Notes: 1) X = Don’t care
2) Set S2 to ON when signal conditioning board is installed in U1; set S2
to OFF when no signal conditioning board is installed.
Topic
Page
2.1 Precautions
2–2
2–3
2–4
2.2 Quick Start List for Platform
2.3 Quick Start List for Stand-Alone
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 on-board 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
7b
7b
1
11
7b
ICC
JP4
C1+
F1
VR1
DC
Power
In/Out
7a
Power
Input
7b
R2
R1
Audio
Power
Amps
Signal Conditioning
Audio
Input
9
Speaker
Output
10
5
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
HP Out
R3
R4
R5
3
2
4
6
2-2
Quick Start
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Quick Start List for Platform
2.2 Quick Start List for Platform
Use the following steps when using the TPA311 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) EnsurethatallexternalpowersourcesaresettoOFF andthattheplatform
power switch S1 is set to OFF
2) Install a TPA311 module in platform sockets U3 and U4 for stereo
operation (or a module in either U3 or U4 for single channel operation),
taking care to align the module pins correctly
3) Use switch S2 to select or bypass the signal conditioning EVM (U1)
4) Set control signal Polarity jumper JP8 to Hi
5) Set jumper JP6 to select the Mode control input (causes the TPA311 to
switch to the single-ended output mode if a plug is inserted into platform
headphone jack J10)
6) If the headphone Jack (J10) output will be used, set Hp source switch S3
to U2–U4.
Table 2–2. Platform Jumper and Switch Settings for the TPA311
EVM
TPA311
Notes: 1) X = Don’t care
JP6
JP7
JP8
Hi
S2
S3
Mode
X
Note 2
X
2) Set S2 to ON when signal conditioning board is installed in U1; set S2
to OFF when no signal conditioning board is installed.
Power supply
7) Select and connect the power supply:
a) Connect an external regulated power supply set to a voltage between
2.0 V and 5.5 V to platform V
to observe marked polarity,
power input connector J6 taking care
or
DD
b) Install a voltage regulator EVM (SLVP097 or equiv.) in platform socket
U6. Install a 9-V battery in B1 or connect a 7 V – 12 V power source
to a platform V
power input (see platform user’s guide)
power input J1 or J2 and jumper the appropriate
CC
Inputs and outputs
8) Ensure that signal source level adjustments and EVM gain, R4, are set to
minimum
9) Connect the audio source to left and right RCA phono jacks J3 and J5 or
stereo miniature phone jack J4
10) Connect 8-Ω – 32-Ω speakers to left and right RCA jacks J7 and J9 or to
stripped wire connectors J8
Power-up
11) Verify correct voltage and input polarity and set the external power supply
to ON. If V and an on-board regulator EVM are used to provide V , set
CC
DD
platform power switch S1 to ON
Platform LED2 should light indicating the presence of V , and the evaluation
DD
modules installed on the platform should begin operation.
12) Adjust the signal source level and EVM gain level (R4) as needed
2-3
Quick Start
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Quick Start List for Stand-Alone
2.3 Quick Start List for Stand-Alone
Use the following steps to use the TPA311 EVM stand-alone or when
connecting it into existing circuits or equipment. Connections to the TPA311
module header pins can be made via individual sockets, wire-wrapping, or
solderingtothepins, eitheronthetoporthebottomofthemodulecircuitboard.
Numbered callouts for selected steps are shown in Figure 2–2 and details
appear in Chapter 3.
Figure 2–2. Quick Start Module Map
2
VDD GND
Shutdown
–3
5
C5
C3
S1
009227
OUT–
R1
GND
6
7
C2
R5
OUT+
U1
R3
C4
Literature #
SLOP116
SE\BTL*
R2
C1
IN+
R4
TPA311
4
GND
EVM
Gain Adjust
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
and GND pins taking care to observe marked polarity
Inputs and outputs
3) Ensure that signal source level adjustments and EVM gain (R4) are set to
minimum
4) Connect the audio source to the module IN+ and GND pins taking care to
observe marked polarity
5) Connect the Shutdown pin to V
through a Normally Open switch
DD
6) For BTL output, connect an 8-Ω – 32-Ω speaker to the module OUT+ and
OUT– pins, or
7) For single-ended output, connect a headphone or an 8-Ω – 32-Ω speaker
to the module OUT+ and GND pins through a 33 µF to 1000 µF output-
coupling capacitor (figure 3–9)
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 and EVM gain level (R4) as needed
2-4
Quick Start
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Chapter 3
Details
This chapter provides details on the TPA311 IC, the evaluation module, and
the steps in the Quick-Start List, additional application information, and a parts
list for the TPA311 evaluation module.
Topic
Page
3.1 Precautions
3–2
3.2 The TPA311 Audio Power Amplifier Evaluation Module
3.2.1 TPA311 Audio Amplifier IC
3.2.2 BTL Operation
3–3
3–4
3–4
3–5
3–5
3–5
3.2.3 Single-Ended Operation
3.2.4 Module Gain
3.2.5 Shutdown
3.3 Using The TPA311 EVM With The Plug-N-Play Evaluation Platform 3–6
3.3.1 Installing and Removing EVM Boards
3.3.2 Signal Routing
3–6
3–7
3.3.3 Mute/Mode
3–8
3.3.4 Power Requirements
3.3.5 Inputs and Outputs
3–10
3–11
3.4 Using The TPA311 EVM Stand-Alone
3.4.1 TPA311 EVM Connected for BTL Output
3.4.2 TPA311 EVM Connected for Single-Ended Output
3–12
3–12
3–13
3.5 TPA311 Audio Power Amplifier Evaluation Module Parts List
3–14
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 on-board 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
HP Out
R3
R4
R5
3-2
Details
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The TPA311 Audio Power Amplifier Evaluation Module
3.2 The TPA311 Audio Power Amplifier Evaluation Module
The TPA311 Audio Power Amplifier Evaluation Module is powered by a
TPA311 350-mW Low-Power Audio Amplifier IC and includes on-board gain
adjustment, a shutdown control signal input with on-board switch, and can be
operated in either the BTL or single-ended output mode.
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 under side of the
board. These pins allow the module to be plugged into the TI 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 to be wired
directly into existing circuits and equipment when used stand-alone.
The module appears in Figure 3–2 and its schematic is shown in Figure 3–3.
Figure 3–2. TPA311 EVM
VDD GND
C5
Shutdown
–3
S1
C3 009227
OUT–
R1
GND
C2
R5
OUT+
U1
C4
Literature #
SLOP116
R3
SE\BTL*
R2
C1
IN+
R4
TPA311
GND
EVM
Figure 3–3. TPA311 EVM Schematic Diagram
VDD
2 V to 5.5 V
GND
C5
10 µF
S1
+
No
1
2
3
8
Shutdown V
Shutdown
O–
7
6
5
R1
20 kΩ
Bypass GND
C2
2.2 µF
OUT–
GND
SE/BTL
In
V
DD
C3
SE/BTL
4
2.2 µF
V
O+
R5
100 kΩ
OUT+
C1
1 µF
C4
5 pF
R3
20 kΩ
R4
200 kΩ
Audio Input+
GND
R2
20 kΩ
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The TPA311 Audio Power Amplifier Evaluation Module
3.2.1 TPA311 Audio Amplifier IC
The TPA311 audio amplifier IC is a CMOS device intended primarily for
bridge-tied load (BTL) operation in battery-powered applications. It is supplied
inaverysmallsurface-mountpackageandhasbeendesignedtooperatefrom
low supply voltages (between approximately 2 V and 5.5 V) and deliver up to
approximately 350 mW into an 8-Ω, BTL (Figure 3–4). Typical applications
include portable phones, toys, games, and similar hand-held audio
applications.
Figure 3–4. TPA311 Amplifier IC
6
V
DD
V
DD
/2
4
_
+
5
IN
V
O
+
2
Bypass
_
+
8
7
V
–
O
1
Bias
Control
Shutdown
3
GND
SE/BTL
The IC includes two separate internal amplifiers and can operate in either the
bridged-tied load (BTL) mode or the single-ended mode as selected by the
SE/BTL pin. In the BTL mode, the two amplifiers operate 180° out-of-phase
with each other for increased power. The speaker load is connected directly
across V + and V –, and neither line is connected to ground. BTL operation
O
O
provides many benefits, including quadruple the output power of single-ended
operation and no need for bulky output coupling capacitors. In the
single-ended mode, one internal amplifier is turned off and the speaker load
is connected between the V + terminal, through an output coupling capacitor,
O
and system ground. For more information, see the TPA311 amplifier IC data
sheet, TI Literature Number SLOS207.
3.2.2 BTL Operation
To operate in the bridge-tied load output mode, the module SE/BTL control
input terminal must be held low. The module output signal from OUT+ must go
throughthespeakerloadandbereturneddirectlytoOUT–, andNOTtosystem
ground. This requires that the OUT– line be isolated not only from system
ground, but also from the OUT– lines of any other amplifiers in the system. The
platform provides such isolated output lines from the amplifier EVM sockets
directly to separate left and right speaker connectors.
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The TPA311 Audio Power Amplifier Evaluation Module
3.2.3 SIngle-Ended Operation
For single-ended operation, the module SE/BTL control input pin must be held
high. The speaker (or headphone) load is connected to the module OUT+
output pin through a coupling capacitor, and to platform/system ground. A
470-µF electrolytic coupling capacitor is provided on the platform in the signal
path to the headphone output jack for this purpose and a control signal from
the platform headphone jack can be routed to the module control input pin to
switch the TPA311 IC to the single-ended mode.
In the single-ended mode, the amplifier inside the TPA311 IC that drives the
OUT– line does not operate and does not dissipate any power. The OUT– pin
goes into a high-impedance state and can be left connected or allowed to float.
3.2.4 Module Gain
The TPA311 evaluation module can be set for an overall gain of between 2 and
22 by adjustment of the the on-board gain control, R4. The TPA311 amplifier
IC, as most other amplifiers, exhibits its best distortion and noise performance
at lower gain levels (see the TPA311 data sheet). Even so, the TPA311 at its
highest gain setting has significantly less distortion than most low-cost
speakers.
Gain versus total harmonic distortion (THD) should be considered in each
application. Both the module input signal level and the TPA311 module gain
should be adjusted to obtain the lowest overall distortion level for a particular
overall gain. A quick rule of thumb (everything else being equal): the module
input signal level should be as high as possible without clipping or overloading
the TPA311 input, and the TPA311 gain kept as low as possible.
3.2.5 Shutdown
When the shutdown terminal of the TPA311 amplifier IC is taken high, the IC
ceases operation and enters an ultra-low power state. This is accomplished
by applying a control signal to the module Shutdown pin or by pressing the
Shutdown switch, S1, on the module. When the control signal goes low or is
removed (or the switch is released), amplifier operation resumes.
The Plug-N-Play platform can generate the shutdown (mute) signal for the
module either when a plug is inserted into the platform headphone output jack
or when the plug is removed, as selected by a platform jumper (JP8).
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Using The TPA311 EVM With the Plug-N-Play Evaluation Platform
3.3 Using The TPA311 EVM With the Plug-N-Play Evaluation Platform
The TPA311 Audio Amplifier Evaluation Module was designed to be used with
the TI Plug-N-Play Audio Amplifier Evaluation Platform. It simply plugs into
socket U3 or U4.
The following paragraphs provide additional details for using the TPA311 EVM
with the platform.
3.3.1 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.
3.3.1.1 EVM Insertion
1) Remove all power from the evaluation platform
2) Locate socket U3 or U4 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
3.3.1.2 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 TPA311 EVM With the Plug-N-Play Evaluation Platform
3.3.2 Signal Routing
Signal flow on the platform is controlled by two signal routing switches, as
shown in Figure 3–5.
Figure 3–5. Platform Signal Routing and Outputs
Off
U3
TPA311
Amplifier EVM
+
–
R
R
L
R
J7, J8, J9
Speaker
Outputs
U1
Signal
Conditioning
Audio
Input
S2
U4
TPA311
Amplifier EVM
–
+
L
L
On
U2–U4
R
+
–
R
U5
Stereo
Headphone
Amplifier
J10
Headphone
Output
GND
S3
L
–
+
L
U5
3.3.2.1 Signal Conditioning
The audio signal from the 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 TPA311 power amplifiers.
Switch S2 selects signal conditioning or bypasses it
3.3.2.2 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 TPA311 power amplifiers installed in sockets U3 and U4, as
determined by the setting of headphone source select switch S3.
When S3 is set to the power amplifier position (U2 – U4), the headphone jack
is connected to the TP311 power amplifier OUT+ output lines. When a plug is
inserted into the jack, signals output through J10 are returned to platform
ground, requiring single-ended power amplifier operation. A switch inside the
headphone jack produces a control signal that can be routed to the power
amplifier sockets to shut down the TPA311 EVMs when a plug is inserted.
Source select switch S3 connects the headphone jack to the output lines of
either the headphone amplifier socket U5, or the power amplifier sockets
(U2 – U4).
To keep the TPA311 amplifier outputs separated, set switch S3 to the
headphone amplifier position (U5) and use the speaker outputs (J7,
J8, and J9)
To route the TPA311 amplifier outputs to the headphone output jack
(J10), set switch S3 to the power amplifier position (U2 – U4) — use
this setting only if the TPA311 EVMs are to drive single-ended loads
connected to J10
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Using The TPA311 EVM With the Plug-N-Play Evaluation Platform
3.3.3 Mute/Mode
The TPA311 EVM is equipped with a mute (shutdown) control input pin. When
this input is tied to V , theTPA311amplifierIConthemoduleshutsdownand
DD
assumes an ultra-low power mode. When the EVM control input is tied to GND
or allowed to float, amplifier operation resumes.
In typical applications, as often found in notebook computers, portable audio
products, and such, 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 shut down (muted) to
conserve power.
A mode control input pin on the EVM switches the TPA311 amplifier IC
between the bridge-tied load (BTL) output mode and the single-ended output
mode. When the mode control input is tied to GND, the module operates in the
BTL output mode. When this input is tied to V , the module operates in the
DD
single-ended output mode.
In the typical application, output mode switching allows the TPA311 to operate
in the BTL output mode for increased power to internal speakers and then
switch to single-ended mode to drive headphones when a plug is inserted into
the headphone jack.
3.3.3.1 Headphone Jack Control Signals
The platform headphone output jack (J10) contains an internal switch that
changesthestateofapairofcontrollineswhenaplugisinserted(Figure3–6).
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 3–6. Mute/Mode and Polarity Control
V
DD
R3
240 Ω
Polarity
JP8
JP6
Mode
Mute
Lo
U3, U4
Power
Amplifiers
J10
Headphone
Jack
Hi
R4
1 kΩ
R5
1 kΩ
SPK
(U2–U4)
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Using The TPA311 EVM With the Plug-N-Play Evaluation Platform
3.3.3.2 Mute/Mode Select (JP6)
A 3-pin jumper header (JP6) on the platform, functioning as a 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.
To mute the TPA311 amplifier module using the control signal from the
platform headphone jack, jumper JP6 to MUTE
To switch the output mode of the TPA311 amplifier between BTL and
single-ended using the control signal from the platform headphone
jack, jumper JP6 to MODE
3.3.3.3 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.
When JP6 is set to Mute, use the following JP8 settings for the TPA311:
To mute the TPA311 amplifier module when a plug is inserted into the
headphone jack, jumper JP8 to Hi (this is the typical setting).
To mute the TPA311 amplifier module until a plug is inserted into the
headphone jack, jumper JP8 to Lo.
When JP6 is set to Mode, use the following JP8 settings for the TPA311:
To switch the TPA311 amplifier module to the single-ended output
mode when a plug is inserted into the headphone jack, jumper JP8 to
Hi (this is the typical setting).
ToswitchtheTPA311amplifiermoduletotheBTLoutputmodewhena
plug is inserted into the headphone jack, jumper JP8 to Lo.
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Power Requirements
3.3.4 Power Requirements
The TPA311 Audio Power Amplifier Evaluation Module can operate from any
voltage between approximately 2 V and 5.5 V, however, the TPA311 amplifier
IC on the module is characterized for operation at 3.3 V and 5 V. For best
performance (highest output power with lowest distortion), the module should
be operated at approximately 5 V unless there is a specific reason for
operating it from a lower voltage.
The TI Plug-N-Play Audio Amplifier Evaluation Platform with a voltage
regulator EVM installed on it can provide a regulated V
supply from a wide
DD
variety of unregulated V
voltage inputs between approximately 5.5 V and
CC
12 V, including an on-board 9-V battery. Or, an external regulated power
source can be used to supply V voltage to the platform and the TPA311
DD
evaluation modules installed on it.
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 TPA311 amplifier IC installed on the
evaluation module (6 V) or damage to the IC may result. In no case should
V
voltage of the incorrect polarity or in excess of 6.1 V be applied to
DD
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
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Inputs and Outputs
3.3.5 Inputs and Outputs
The TI Plug-N-Play Audio Amplifier Evaluation Platform is equipped with
several standard conectors for audio inputs and outputs.
3.3.5.1 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.
3.3.5.2 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 TPA311 power amplifier EVMs to operate in the highly-efficient
bridge-tied load configuration.
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 3–5). When the TPA311 output
signal is routed to J10 by S3, signals output via J10 are returned to platform
ground when a plug is inserted (Figure 3–7), requiring single-ended operation
of the power amplifiers.
Figure 3–7. Typical Headphone Plug
Left
Right
GND
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Using The TPA311 EVM Stand-Alone
3.4 Using The TPA311 EVM Stand-Alone
Using the TPA311 Audio Power Amplifier Evaluation Module stand-alone is
much the same as using it with the platform. The same 2-V to 5.5-V power sup-
ply range and the isolated OUT+ and OUT– lines for BTL operation require-
ment exists.
Note that the mute signal applied to the EVM shutdown pins must be able to
supply enough current to overcome the pulldown resistors on the modules
(20 kΩ || 20 kΩ for two EVMs).
3.4.1 TPA311 EVM Connected for BTL Output
Figure 3–8. TPA311 EVM Connected for Stereo BTL Output
5 VDC
VDD GND
Shutdown
–3
C5
S1
R1
C3
009227
OUT–
GND
Right
C2
R5
OUT+
U1
C4
Literature #
SLOP116
R3
SE\BTL*
R2
Audio
Input
(Right)
C1
IN+
R4
TPA311
GND
EVM
GND
5 VDC
VDD GND
Shutdown
–3
External Mute
Control
(active high)
C5
C3
S1
009227
OUT–
R1
GND
Left
C2
R5
OUT+
U1
R3
C4
Literature #
SLOP116
SE\BTL*
R2
Audio
Input
(Left)
C1
IN+
R4
TPA311
GND
EVM
Note: The SE/BTL* (SE/BTL) EVM pin is pulled to GND through a 100-KΩ resistor on the mod-
ule.
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Using The TPA311 EVM Stand-Alone
3.4.2 TPA311 EVM Connected for Single-Ended Output
Figure 3–9. TPA311 EVM Connected for Stereo Single-Ended Output
5 VDC
VDD GND
Shutdown
–3
C5
S1
R1
C3 009227
OUT–
GND
C2
R5
OUT+
U1
C4
Literature #
SLOP116
R3
SE\BTL*
R2
+
33 µF –
1000 µF
Audio
Input
(Right)
C1
IN+
R4
TPA311
GND
EVM
GND
5 VDC
VDD GND
Shutdown
–3
External Mute
Control
(active high)
C5
33 µF –
S1
C3
009227
OUT–
1000 µF
+
R1
GND
C2
R5
OUT+
U1
C4
Literature #
SLOP116
R3
SE\BTL*
R2
Audio
Input
(Left)
C1
IN+
R4
TPA311
GND
EVM
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TPA311 Audio Power Amplifier Evaluation Module Parts List
3.5 TPA311 Audio Power Amplifier Evaluation Module Parts List
Table 3–1. TPA311 EVM Parts List
EVM
Qty.
Manufacturer/
Part Number
Ref.
R4
Description
Size
Digi-Key Number
Trim Pot, 200 kΩ Cermet
ST SL, (through hole)
1
1
1
Bourns
3323P-1-204
Digi-Key
3323P-204-ND
C5
C1
Capacitor, 10 µF, 6.3 V
A
Panasonic
ECS-TOJY106R
Digi-Key
PCS1106CT-ND
Capacitor, 1 µF,
+80%/–20%,
nonpolarized
1206
Murata
Newark
GRM42-6Y5V105Z16BL 93F2254
C2, C3
C4
Capacitor, 2.2 µF, 20%,
1206
0805
1206
2
1
3
1
1
1
TDK
C3216X5R1A225
nonpolarized
Capacitor, 5 pF
Panasonic
ECU-V1H050CCN
Digi-Key
PCC050CNCT-ND
R1, R2, Resistor, 20 kΩ, 1/8 W,
R3
Panasonic
ERJ-8GEYJ203
Digi-Key
P20KECT-ND
5%
S1
Switch, momentary
Panasonic
P8048SCT-ND
Digi-Key
P8048SCT-ND
U1
IC, TPA311, audio
amplifier, 350 mW, mono
SOIC
-8
TI
TPA311
PCB1
PCB, TPA311 sample
EVM
NOTE: All items are SMD except as noted.
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