Texas Instruments SLOU023A User manual

TPA112 MSOP
Audio Power Amplifier
Evaluation Module
2001 Mixed-Signal Products
User’s Guide
SLOU023A

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Copyright 2001, Texas Instruments Incorporated

iii
Chapter Title—Attribute Reference
Preface
Related Documentation From Texas Instruments
J 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.
J TPA112 150-mW Stereo Audio Power Amplifier (literature
number SLOS212) This is the data sheet for the TPA112 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
testedforcompliancewiththelimitsofcomputingdevices pursuant to subpart
Jofpart 15ofFCCrules,whicharedesignedtoprovidereasonableprotection
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.

iv

Running Title—Attribute Reference
v
Chapter Title—Attribute Reference
Contents
1 Introduction 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Feature Highlights 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 TPA112 MSOP EVM Specifications 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Quick Start 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 Precautions 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Quick Start List for Platform 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Quick Start List for Stand-Alone 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Details 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Precautions 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 The TPA112 MSOP Audio Amplifier Evaluation Module 3-3. . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 TPA112 Audio Amplifier IC 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Module Gain 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Using The TPA112 MSOP 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 Power Requirements 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.5 Inputs and Outputs 3-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Using The TPA112 MSOP EVM Stand-Alone 3-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1 TPA112 MSOP EVM Connected as a Stereo Headphone Amplifier 3-10. . . . . . . .
3.5 TPA112 MSOP Audio Amplifier Evaluation Module Parts List 3-11. . . . . . . . . . . . . . . . . . . .

Running Title—Attribute Reference
vi
Figures
1–1 The TI TPA112 MSOP Audio Amplifier Evaluation Module 1-3. . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 Quick Start Platform Map 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Quick Start Module Map 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–1 The TI Plug-N-Play Audio Amplifier Evaluation Platform 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–2 TPA112 MSOP EVM 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–3 TPA112 MSOP EVM Schematic Diagram 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4 TPA112 Audio Amplifier IC 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–5 Platform Signal Routing and Outputs 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–6 Typical Headphone Plug 3-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–7 TPA112 MSOP EVM Connected as a Stereo Headphone Amplifier 3-10. . . . . . . . . . . . . . . . .
Tables
2–1 Typical TI Plug-N-Play Platform Jumper and Switch Settings for the
TPA112 MSOP EVM 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Platform Jumper and Switch Settings for the TPA112 MSOP EVM 2-3. . . . . . . . . . . . . . . . . . .
3–1 TPA112 MSOP EVM Parts List 3-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1
Introduction
Introduction
This chapter provides an overview of the Texas Instruments (TI) TPA112
MSOPaudioamplifierevaluationmodule(SLOP126).Itincludes 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 Features 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 TPA112 MSOP EVM Specifications 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1

Features
1-2 Introduction
1.1 Features
The TI TPA112 MSOP audio amplifier evaluation module and the TI
plug-n-play audio amplifier evaluation platform include the following features:
- TPA112 MSOP Stereo Audio Power Amplifier Evaluation Module
J Dual channel, single-ended operation
J 150-mW output power per channel into 8 Ωat 5 V
J 2.5-V to 5.5-V operation
J Distortion—THD+Nisless than0.01%@1kHz andlessthan0.02%
from 20 Hz to 20 kHz into 10-kΩloads; less than 0.06% @ 1 kHz and
lessthan1%from20Hzto20kHzinto32-Ωloads;andlessthan0.1%
@ 1 kHz and less than 2% from 20 Hz to 20 kHz into 8-Ωloads
J Internal thermal and short-circuit protection
- Quick and Easy Configuration With the TI Plug-N-Play Audio Amplifier
Evaluation Platform
J Evaluation module is designed to simply plug into the platform,
automatically making all signal, control, and power connections
J Platform provides flexible power options
J Jumpers on the platform select power and module control options
J Switches on the platform route signals
J Platformprovides quick and easyaudio input and outputconnections
- Platform Power Options
J Onboard 9-V battery
J External 5-V –15-V (VCC) supply inputs
J External regulated VDD supply input
J Socket for onboard 5-V VDD voltage regulator EVM
J Onboard overvoltage and reverse polarity power protection
- Platform Audio Input and Output Connections
J Left and right RCA phono jack inputs
J Miniature stereo phone jack input
J Left and right RCA phono jack outputs
J Left and right compression speaker terminal outputs
J Miniature stereo headphone jack output

Description
1-3
Introduction
1.2 Description
The TPA112 MSOP audio power amplifier evaluation module is a complete,
low-power stereo audio power amplifier for high-fidelity line-level output,
headphone, and small speaker applications. It consists of the TI TPA112
150-mWstereoaudiopoweramplifierICinaverysmallMSOPpackage,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 TPA112 Audio Amplifier Evaluation Module
GND
Vo2
IN2–
IN2+
Vdd GND
IN1+
U2 C7 R9
C1
C5
Vo1
GND
TEXAS
INSTRUMENTS
SLOP126
TPA112 MSOP EVM
C6
R10
R8
R7C4
R1
R2
R3
R4
C2
R5
R6
C3 JP1
IN1–
+
†Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD
Single in-line header pins are mounted to 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.
The platform has room for a single TPA112 evaluation module. It is a
convenient vehicle for demonstrating TI’s audio power amplifier and related
evaluation modules. The EVMs simply plug 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 TPA112 MSOP EVM Specifications
Supply voltage range, VDD 2.5 V to 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply current, IDD 160 mA, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous output power, PO:8Ω, VDD=5 V 150 mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio input voltage, VIVDD + 0.3 Vpp, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Minimum load impedance, RL8 Ω. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4 Introduction

2-1
Quick Start
Quick Start
ThestepsinthischaptercanbefollowedtoquicklypreparetheTPA112MSOP
audio amplifier EVM for use. Using the TPA112 MSOP EVM with the TI
plug-n-play audio amplifier evaluation platform is a quick and easy way to
connectpower, signal andcontrolinputs, and signal outputs to theEVMusing
standard connectors. However, 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.
TheplatformswitchandjumpersettingsshowninTable2–1aretypicalforthe
TPA112 MSOP EVM.
Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the
TPA112 MSOP EVM
EVM JP6 JP7 JP8 S2 S3
TPA112 X X X Note 2 U5
Notes: 1) X = Don’t care
2) SetS2 to ONwhen signalconditioning boardis installedinU1; set S2
to OFF when no signal conditioning board is installed.
Topic Page
2.1 Precautions 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Quick Start List for Platform 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Quick Start List for Stand-Alone 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 2

Precautions
2-2 Quick Start
2.1 Precautions
Power Supply Input Polarity and Maximum Voltage
Always ensure that the polarity and voltage of the external power
connected to VCC power input connector J1, J2, and/or VDD power
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
Donotinsertor remove EVM boardswithpowerapplied —damage
to the EVM board, the platform, or both may result.
Figure 2–1.Quick Start Platform Map
3
Signal Conditioning
****CAUTION****
Do not insert or remove
EVM boards with power
applied
ICC
JP4
F1
VR1
R1
JP3 JP2 JP1 AC/DC
(J2)
VCC(J1)
D1 D2 D3
D4 J2
J3 J4 J5
AC/DC
In
VCC
In
+
J1
DC
SOURCE
LED1 VCC
LED2 VDD
R2
JP5 IDD
B1
U6
POWER
SUPPLY
U3 U4
U5
U1
U2
Audio
Power
Amps
OnOff ConditioningS2
J7 J8 Right
Out Left
Out
+–+–
JP6
Mode
Mute
Spk(U2-U4)
JP8
J9 Left
Out
JP7
S3 HP Source
U2-U4
U5
Polarity
Lo
Hi
HP(U5)
C3 C2
++
R3
R4 R5
J10
Stereo
HP Out
TP1
GND
Plug-N-PlayAudio Amplifier
Evaluation Platform
SLOP097 Rev. C.1
Stereo
In
Right
In Left
In
J6 In/Out VDD
F2
VR2
+
DC
Power
In/Out
Speaker
Output
Headphone
Output
Audio
Input
Power
Input
Batt
C1+
Right
Out
On Off Pwr
S1
TEXAS INSTRUMENTS 1997
110
8
7
5b
5b
5a
5b 5b
24

Quick Start List for Platform
2-3
Quick Start
2.2 Quick Start List for Platform
FollowthesestepswhenusingtheTPA112MSOPEVMwiththeTIplug-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) EnsurethatallexternalpowersourcesaresettoOFFandthattheplatform
power switch S1 is set to OFF.
2) InstallaTPA112MSOPmoduleinplatformsocketU5, takingcaretoalign
the module pins correctly.
3) Use switch S2 to select or bypass the signal conditioning EVM (U1).
4) SetHpsource switchS3toU5 toroutetheoutputsignaltotheheadphone
Jack (J10).
Table 2–2. Platform Jumper and Switch Settings for the TPA112 MSOP EVM
EVM JP6 JP7 JP8 S2 S3
TPA112 X X X Note 2 U5
Notes: 1) X = Don’t care
2) SetS2 to ON whensignal conditioning boardis installedin U1; set S2
to OFF when no signal conditioning board is installed.
- Power supply
5) Select and connect the power supply:
a) Connectanexternalregulatedpowersupplysettoa voltage between
2.5Vand5.5VtoplatformVDD powerinputconnectorJ6,takingcare
to observe marked polarity, or
b) Install a 3-V to 5-V voltage regulator EVM (SLVP097 or equiv.) in
platform socket U6. Install a 9-V battery in B1 or connect a 7 V –12
VpowersourcetoaplatformVCCpowerinputJ1orJ2andjumperthe
appropriate power input (see platform user’s guide).
- Inputs and outputs
6) Ensure that signal source level is set to minimum.
7) Connect the audio source to left and right RCA phono jacks J3 and J5 or
stereo miniature phone jack J4.
8) Connect 32-Ωheadphones to headphone jack J10.
- Power up
9) Verify correct voltage andinput polarity and setthe external power supply
toON.If VCC andanonboardregulatorEVMareusedtoprovide VDD,set
platform power switch S1 to ON.
PlatformLED2shouldlightindicatingthepresenceofVDD,andtheevaluation
modules installed on the platform should begin operation.
10) Adjust the signal source level as needed.

Quick Start List for Stand-Alone
2-4 Quick Start
2.3 Quick Start List for Stand-Alone
Follow these steps to use the TPA112 MSOP EVM stand-alone or to connect
it into existing circuits or equipment. Connections to the TPA112 MSOP
module header pins can be made via individual sockets, wire-wrapping, or
solderingtothepins,eitheronthetoporthebottomofthemodulecircuitboard
(Figure 2–2). Details appear in Chapter 3.
Figure 2–2.Quick Start Module Map
GND
Vo2
IN2–
IN2+
Vdd GND
IN1+
U2 C7 R9
C1
C5
Vo1
GND
TEXAS
INSTRUMENTS
SLOP126
TPA112 MSOP EVM
C6
R10
R8
R7C4
R1
R2
R3
R4
C2
R5
R6
C3 JP1
IN1–
+
†Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD
- Power supply
1) Ensure that all external power sources are set to OFF.
2) Connectanexternalregulated powersupplysetto5V tothemoduleVDD
and GND pins, taking care to observe marked polarity.
- Inputs and outputs
3) Ensure that the signal source level is set to minimum.
4) Connectadifferentialaudiosignalsource between module pins IN1+ and
IN1–(right channel) and between pins IN2+ and IN2–(left channel). If a
single-ended audio source is used, connect it to IN1–and IN2–(right and
left channels), and ground both IN1+ and IN2+.
5) Connect 32-Ωheadphones to the module VO1, VO2pins through 33 µF
to1000 µF output-coupling capacitors (figure 3–8) and return tothe GND
pin, or
6) For line output, connections to the VO1and VO2pins must be made
through 33 µF to 1000 µF output-coupling capacitors and returned to
GND.
- Power-up
7) Verify correct voltage andinput polarity and setthe external power supply
to ON.
The EVM should begin operation.
8) Adjust the signal source level as needed.

3-1
Details
Details
This chapter provides details on the TPA112 IC, the evaluation module, the
stepsintheQuick-StartList, additionalapplicationinformation,andaparts list
for the TPA112 MSOP evaluation module.
Topic Page
3.1 Precautions 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 The TPA112 MSOP Audio Power Amplifier Evaluation Module 3–3. . . .
3.3 Using The TPA112 MSOP EVM With The Plug-N-Play
Evaluation Platform 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Using The TPA112 MSOP EVM Stand-Alone 3–10. . . . . . . . . . . . . . . . . . .
3.5 TPA112 MSOP Audio Power Amplifier EVM Parts List 3–11. . . . . . . . . . .
Chapter 3

Precautions
3-2 Details
3.1 Precautions
Power Supply Input Polarity and Maximum Voltage
Always ensure that the polarity and voltage of the external power
connected to VCC power input connector J1, J2, and/or VDD power
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
Donotinsertor remove EVM boardswithpowerapplied —damage
to the EVM board, the platform, or both may result.
Figure 3–1.The TI Plug-N-Play Audio Amplifier Evaluation Platform
Signal Conditioning
****CAUTION****
Do not insert or remove
EVM boards with power
applied
ICC
JP4
F1
VR1
R1
JP3 JP2 JP1 AC/DC
(J2)
VCC(J1)
D1 D2 D3
D4 J2
J3 J4 J5
AC/DC
In
VCC
In
+
J1
DC
SOURCE
LED1 VCC
LED2 VDD
R2
JP5 IDD
B1
U6
POWER
SUPPLY
U3 U4
U5
U1
U2
Audio
Power
Amps
OnOff ConditioningS2
J7 J8 Right
Out Left
Out
+–+–
JP6
Mode
Mute
Spk(U2-U4)
JP8
J9 Left
Out
JP7
S3 HP Source
U2-U4
U5
Polarity
Lo
Hi
HP(U5)
C3 C2
++
R3
R4 R5
J10
Stereo
HP Out
TP1
GND
Plug-N-PlayAudio Amplifier
Evaluation Platform
SLOP097 Rev. C.1
Stereo
In
Right
In Left
In
J6 In/Out VDD
F2
VR2
+
DC
Power
In/Out
Speaker
Output
Headphone
Output
Audio
Input
Power
Input
Batt
C1+
Right
Out
On Off Pwr
S1
TEXAS INSTRUMENTS 1997

The TPA112 MSOP Audio Power Amplifier Evaluation Module
3-3
Details
3.2 The TPA112 MSOP Audio Power Amplifier Evaluation Module
The TPA112 MSOP audio power amplifier evaluation module is powered by
a TPA112 150-mW stereo audio amplifier IC. It can drive either line-level
outputs, 32-Ωheadphones, or 8-Ωspeakers. A single-supply operational
amplifier (TLV2211) on the module provides a buffered midpoint voltage to
properly bias the noninverting inputs of the TPA112 amplifier IC.
The evaluation 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,whichautomaticallymakesallthesignalinputandoutput,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 and its schematic is shown in Figure 3–3.
Figure 3–2.TPA112 MSOP EVM
GND
Vo2
IN2–
IN2+
Vdd GND
IN1+
U2 C7 R9
C1
C5
Vo1
GND
TEXAS
INSTRUMENTS
SLOP126
TPA112 MSOP EVM
C6
R10
R8
R7C4
R1
R2
R3
R4
C2
R5
R6
C3 JP1
IN1–
+
†Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD
Figure 3–3.TPA112 MSOP EVM Schematic Diagram
IN 1–
Vo1 VDD
Vo2
GND IN 2–
C3
1 µF
R7
20 kΩ
C4
0.1 µF8
7
6
5
1
2
3
4
Vo2
Audio
Input 1
R10
82 kΩ
TPA112
MSOP
C6
1 µF
+VDD
2.5 to 5.5 V
GND
C5
10 µF
Vo1
R8
82 kΩ
IN 1+
IN 2+
R9
20 kΩ
C7
0.1 µF
Audio
Input 2
R1
20 kΩ
C1
0.1 µF
R4
20 kΩ
C2
0.1 µF
_
+
R6, 20 kΩ
R5
20 kΩ
VDD
Mid
Mid
R2
82 kΩ
R3
82 kΩU1
U2
IN+
IN–
IN+
IN–

The TPA112 MSOP Audio Power Amplifier Evaluation Module
3-4 Details
3.2.1 TPA112 Audio Amplifier IC
The TPA112 audio amplifier IC is a CMOS device intended primarily for
high-performance line-level output, headphone driver, and small speaker
applications. It is supplied in both a SOIC and a very small surface-mount
MSOP package and has been designed to operate from low supply voltages
(between approximately 2.5 V and 5.5 V) and to deliver up to approximately
150 mW into 8-Ωspeakers. As a line-level driver, distortion levels (THD+N)
are below 0.02% into 10-kΩloads across the audio band (20 Hz to 20 kHz).
As a headphone driver, distortion levels are below 1% into 32-Ωloads across
the audio band. And as a speaker driver, distortion levels are below 2% into
8-Ωloads across the audio band. Typical applications include portable
computers, desktop computers, personal audio, toys, games, and similar
audio applications.
TheICincludestwoseparateinternalamplifierswithonboardshort-circuitand
over-temperature protection circuits (Figure 3–4). The load for each channel
is connected between the VOpin and GND through a coupling capacitor. For
more information, see the TPA112 amplifier IC data sheet, TI Literature
Number SLOS212.
Figure 3–4.TPA112 Amplifier IC
Over-Temperature
Protection
8
1
7
4
VO1
VO2
VDD
5
2
6
IN1–
IN2–
VDD
IN2+
IN1+3
Short-Circuit
Protection
–
+
–
+

The TPA112 MSOP Audio Power Amplifier Evaluation Module
3-5
Details
3.2.2 Module Gain
The TPA112 MSOP evaluation module has a set gain of 4 (inverting) for each
channel. However, the gain can be adjusted to a maximum of approximately
10(inverting)bychangingthevalueoffeedbackresistors(R8andR10,Figure
3–3). Use the following equation to determine the value of RF:
Gain + –RF
RI
The TPA112 amplifier IC, like most other amplifiers, exhibits its best distortion
and noise performance at lower gain levels. In addition, higher gain levels
require a small compensation capacitor to ensure stability (see the TPA112
data sheet).
Gain versus total harmonic distortion (THD) and gain versus signal-to-noise
ratio (SNR) should be considered in each application. Both the module input
signal level and the TPA112 MSOP 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 TPA112 input, and the
TPA112 gain should be kept as low as possible.

Using The TPA112 MSOP EVM With the Plug-N-Play Evaluation Platform
3-6 Details
3.3 Using The TPA112 MSOP EVM With the Plug-N-Play Evaluation Platform
TheTPA112MSOPaudioamplifierevaluationmoduleisdesignedforusewith
the TI plug-n-play audio amplifier evaluation platform. It simply plugs into
socket U5.
ThefollowingparagraphsprovideadditionaldetailsforusingtheTPA112EVM
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 U5 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 short distance.
3) Changetothe oppositesideofthemoduleandusethetooltoprythatside
up a short distance.
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 the platform.