Texas Instruments SLOU023A User Manual

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TPA112 MSOP Audio Power Amplifier Evaluation Module

User’s Guide

2001 Mixed-Signal Products

SLOU023A

IMPORTANT NOTICE

T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its products to the specifications applicable at the time of sale in accordance with TI’s standard warranty . T esting 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.

Customers are responsible for their applications using TI components. In order to minimize risks associated with the customer’s applications, adequate design and operating

safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not 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 products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, license, warranty or endorsement thereof.

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Also see: Standard Terms and Conditions of Sale for Semiconductor Products.

Mailing Address:

Texas Instruments Post Office Box 655303 Dallas, Texas 75265

www.ti.com/sc/docs/stdterms.htm

stated by TI for

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.

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 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.

Preface

Trademarks

TI is a trademark of Texas Instruments Incorporated.

Chapter Title—Attribute Reference

iii

Running 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. . . . . . . . . . . . . . . . . . . .

Chapter Title—Attribute Reference

Running Title—Attribute Reference

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

2–2 Platform Jumper and Switch Settings for the TPA112 MSOP EVM 2-3. . . . . . . . . . . . . . . . . . .

3–1 TPA112 MSOP EVM Parts List 3-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TPA112 MSOP EVM 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 1

Introduction

This chapter provides an overview of the Texas Instruments (TI) TPA112 MSOP audio amplifier evaluation module (SLOP126). 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 Features 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.2 Description 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.3 TP A112 MSOP EVM Specifications 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction

1-1

Features

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

Dual channel, single-ended operation

150-mW output power per channel into 8 Ω at 5 V

2.5-V to 5.5-V operation

Distortion — THD+N is less than 0.01% @ 1 kHz and less than 0.02% from 20 Hz to 20 kHz into 10-kΩ loads; less than 0.06% @ 1 kHz and less than 1% from 20 Hz to 20 kHz into 32-Ω loads; and less than 0.1% @ 1 kHz and less than 2% from 20 Hz to 20 kHz into 8-Ω loads

Internal thermal and short-circuit protection

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

Onboard 9-V battery

External 5-V – 15-V (VCC) supply inputs

External regulated VDD supply input

Socket for onboard 5-V VDD voltage regulator EVM

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

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-mW stereo audio power amplifier IC in a very small MSOP package, 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

Description

TEXAS

INSTRUMENTS

IN1– IN1+

IN2– IN2+

†

Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD

C1 R1

R2 R3 R4 C2

JP1

TPA112 MSOP EVM

Vdd GND

SLOP126

R7C4

Vo1

GND

R10

GND

Vo2

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, and connects them to a versatile array of standard audio input and output jacks 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, V Supply current, I

Continuous output power, P Audio input voltage, V Minimum load impedance, R

:8 Ω, VDD=5 V 150 mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.5 V to 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VDD + 0.3 Vpp, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction

160 mA, max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8 Ω. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-3

1-4

Introduction

Chapter 2

Quick Start

The steps in this chapter can be followed to quickly prepare the TP A112 MSOP 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 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 can be wired directly into existing circuits or equipment.

The platform switch and jumper settings shown in T able 2–1 are typical for the 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) 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 Quick Start List for Platform 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Quick Start List for Stand-Alone 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quick Start

2-1

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 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

power input connector J1, J2, and/or VDD power

Power

Input

Audio Input

AC/DC

SOURCE

VCC

VCC(J1)

Right

Stereo

Left

TEXAS

INSTRUMENTS

1997

JP1

AC/DC

(J2)

Batt

VR1

VCC

C1+

LED1

JP3

JP2

Signal Conditioning

****CAUTION**** Do not insert or remove EVM boards with power

applied

Plug-N-Play Audio Amplifier Evaluation Platform SLOP097 Rev. C.1

110

Off Pwr

ConditioningS2

GND

Audio Power Amps

OnOff

TP1

ICC JP4

IDD

JP5

U3 U4

U2-U4

Source

SUPPLY

HP(U5)

POWER

LED2

VDD

JP6

Polarity

Lo Hi

JP7

Out

Mode Mute

Spk(U2-U4)

JP8

C3 C2

HP Out

Right

Out

Left

Out

Stereo

+ – + – Right

Left

VR2

In/Out

VDD

J10

DC Power In/Out

Speaker Output

Headphone Output

2-2

Quick Start

Quick Start List for Platform

2.2 Quick Start List for Platform

Follow these steps when using the TP A112 MSOP 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 and that the platform power switch S1 is set to OFF.

2) Install a TP A1 12 MSOP module in platform socket U5, taking care to align the module pins correctly.

3) Use switch S2 to select or bypass the signal conditioning EVM (U1).

4) Set Hp source switch S3 to U5 to route the output signal to the headphone 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) 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

5) Select and connect the power supply: a) Connect an external regulated power supply set to a voltage between

2.5 V and 5.5 V to platform V

power input connector J6, taking care

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 V power source to a platform V

power input J1 or J2 and jumper the

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-Ω headphones to headphone jack J10.

Power up

9) Verify correct voltage and input polarity and set the external power supply to ON. If V

and an onboard regulator EVM are used to provide VDD, set

platform power switch S1 to ON.

Platform LED2 should light indicating the presence of V

, and the evaluation

modules installed on the platform should begin operation.

10) Adjust the signal source level as needed.

Quick Start

2-3

Quick Start List for Stand-Alone

2.3 Quick Start List for Stand-Alone

Follow these steps to use the TP A112 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 soldering to the pins, either on the top or the bottom of the module circuit board (Figure 2–2). Details appear in Chapter 3.

Figure 2–2.Quick Start Module Map

TEXAS

INSTRUMENTS

IN1– IN1+

IN2– IN2+

†

Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD

Power supply

C1 R1

R2 R3 R4 C2

JP1

TPA112 MSOP EVM

Vdd GND

SLOP126

R7C4

Vo1

GND

R10

GND

Vo2

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 the signal source level is set to minimum.

4) Connect a differential audio signal source 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+.

2-4

Power-up

5) Connect 32-Ω headphones to the module V

1, VO2 pins through 33 µF

to 1000 µF output-coupling capacitors (figure 3–8) and return to the GND pin, or

6) For line output, connections to the V

1 and VO2 pins must be made

through 33 µF to 1000 µF output-coupling capacitors and returned to GND.

7) Verify correct voltage and input polarity and set the external power supply to ON.

The EVM should begin operation.

8) Adjust the signal source level as needed.

Quick Start

Chapter 3

Details

This chapter provides details on the TPA112 IC, the evaluation module, the steps in the Quick-Start List, additional application information, and a parts 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. . . . . . . . . . .

Details

3-1

Precautions

3.1 Precautions

Power Supply Input Polarity and Maximum Voltage Always ensure that the polarity and voltage of the external power

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

JP3

JP2

JP1

SOURCE

Power

Input

Audio Input

AC/DC

VCC

Right

Stereo

Left

VCC(J1)

AC/DC

(J2)

Signal Conditioning

Batt

VR1

VCC

C1+

LED1

power input connector J1, J2, and/or VDD power

Off Pwr

ICC JP4

JP5

IDD

Audio Power Amps

OnOff

ConditioningS2

U3 U4

SUPPLY

POWER

LED2

VDD

Out

Right

Out

+ – + – Right

Left

VR2

In/Out

VDD

DC Power In/Out

Speaker Output

3-2

TEXAS

INSTRUMENTS

1997

Plug-N-Play Audio Amplifier Evaluation Platform SLOP097 Rev. C.1

****CAUTION**** Do not insert or remove EVM boards with power

applied

GND

TP1

U2-U4

Source

HP(U5)

JP6

Polarity

JP7

Mode Mute

Spk(U2-U4)

Out

JP8

C3 C2

HP Out

Left

Stereo

J10

Headphone Output

Details

The TPA112 MSOP Audio Power Amplifier Evaluation Module

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-Ω headphones, or 8-Ω speakers. 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, 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 and its schematic is shown in Figure 3–3.

Figure 3–2.TPA112 MSOP EVM

TEXAS

INSTRUMENTS

IN1– IN1+

IN2– IN2+

†

Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD

C1 R1

R2 R3 R4 C2

JP1

TPA112 MSOP EVM

Vdd GND

SLOP126

R7C4

Vo1

GND

R10

GND

Vo2

Figure 3–3.TPA112 MSOP EVM Schematic Diagram

1 µF

Vo1 V

2.5 to 5.5 V

GND

Vo2

IN–

Audio

Input 1

IN+

Audio

Input 2

IN–

0.1 µF

20 kΩ

R8 82 kΩ

82 kΩ

Mid

82 kΩ

Vo1

IN 1–

IN 1+

TPA112

MSOP

GND

Vo2

IN 2– IN 2+

10 µF

R10 82 kΩ

6 5

Mid

1 µF

20 kΩ

+ _

R6, 20 kΩ

Details

3-3

The TPA112 MSOP Audio Power Amplifier Evaluation Module

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-Ω speakers. As a line-level driver, distortion levels (THD+N) are below 0.02% into 10-kΩ loads across the audio band (20 Hz to 20 kHz). As a headphone driver, distortion levels are below 1% into 32-Ω loads across the audio band. And as a speaker driver, distortion levels are below 2% into 8-Ω loads across the audio band. Typical applications include portable computers, desktop computers, personal audio, toys, games, and similar audio applications.

The IC includes two separate internal amplifiers with onboard short-circuit and over-temperature protection circuits (Figure 3–4). The load for each channel is connected between the V

pin 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

Short-Circuit

Protection

IN1–

IN1+3

IN2–

IN2+

Over-Temperature

Protection

–

VO1

VO2

3-4

Details

3.2.2 Module Gain

The TPA112 MSOP Audio Power Amplifier Evaluation Module

The TP A1 12 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) by changing the value of feedback resistors (R8 and R10, Figure 3–3). Use the following equation to determine the value of R

Gain+–

The TP A1 12 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 TP A1 12 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 TP A112 input, and the TPA112 gain should be kept as low as possible.

Details

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Using The TP A112 MSOP EVM With the Plug-N-Play Evaluation Platform

3.3 Using The TPA112 MSOP EVM With the Plug-N-Play Evaluation Platform

The TP A112 MSOP audio amplifier evaluation module is designed for use with the TI plug-n-play audio amplifier evaluation platform. It simply plugs into socket U5.

The following paragraphs provide additional details for using the TP A112 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

3.3.1.2 EVM Removal

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.

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) Change to the opposite side of the module and use the tool to pry that side 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.

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5) Lift the EVM off the platform.

Details

Using The TP A112 MSOP 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

U2 Stereo Power

Amplifier EVM

Off

Audio

Input

Signal

Conditioning

Mono Power

Amplifier EVM

Mono Power

Amplifier EVM

TPA112 MSOP

Headphone

Amplifier EVM

GND

–

J7, J8, J9

Speaker Outputs

–

J10

Headphone

Output

–

U2–U4

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 TP A112 power amplifiers.

Switch S2 selects or bypasses signal conditioning.

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). It can output either the signal from the the TP A112 MSOP headphone amplifier in socket U5 or the signal from power amplifiers installed in socket U2 or in sockets U3 and U4, as determined by the setting of headphone source select switch S3.

When S3 is set to the headphone amplifier position (U5), the headphone jack is connected to the headphone amplifier EVM output lines. When a plug is inserted into the jack, signals output through J10 are returned to platform ground.

Switch S3 connects the headphone jack to either the headphone amplifier platform socket (U5) or to the platform power amplifier sockets (U2 – U4).

Details

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Using The TP A112 MSOP EVM With the Plug-N-Play Evaluation Platform

3.3.3 Power Requirements

The TP A112 MSOP audio power amplifier evaluation module can operate from a VDD voltage between approximately 2.5 V and 5.5 V.

The TI plug-n-play audio amplifier evaluation platform with a voltage regulator EVM installed on it can provide a regulated 3.3-V or 5-V V wide variety of unregulated V and 12 V, including an onboard 9-V battery. Or, an external regulated power source can be used to supply V evaluation module installed on it.

The platform is equipped with overvoltage and reverse-polarity supply voltage input protection in the form of fused crowbar circuits.

VDD voltage applied to platform screw terminals J6 MUST NOT exceed the absolute maximum rating for the TP A112 amplifier IC installed on the evaluation module (5.5 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 screw terminals J6 of the platform, or the power protection circuit on the

line will trip.

VCC voltage applied to the platform MUST NOT exceed the maximum 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 15 V, or the overvoltage protection circuit on the V

voltage inputs between approximately 5.5 V

voltage to the platform and the TPA112

voltage applied to the platform exceed

supply from a

bus will trip.

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Details

3.3.4 Inputs and Outputs

The TI plug-n-play audio amplifier evaluation platform is equipped with several standard conectors for audio inputs and outputs.

3.3.4.1 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.

3.3.4.2 Outputs

Output signals from the headphone amplifier (U5) leave the platform through a miniature (1/8″) stereo headphone jack (J10). Amplified audio output signals from the power amplifiers (U2 – U4) 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 the headphone jack.

Using The TP A112 MSOP EVM With the Plug-N-Play Evaluation Platform

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 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 TPA1 12 MSOP EVM output signal is routed to J10 by S3, signals output via J10 are returned to platform ground when a plug is inserted (Figure 3–6).

Figure 3–6.Typical Headphone Plug

Left Right GND

Details

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Using The TP A112 MSOP EVM Stand-Alone

3.4 Using The TPA112 MSOP EVM Stand-Alone

Using the TPA112 MSOP audio power amplifier evaluation module stand-alone is much the same as using it with the platform. The same 2.5-V to 5.5-V power supply requirement exists.

3.4.1 TPA112 MSOP EVM Connected as a Stereo Headphone Amplifier

Figure 3–7.TPA112 MSOP EVM Connected as a Stereo Headphone Amplifier

5 VDC

TEXAS

Audio

Input

(Right)

Audio

Input

(Left)

†

Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD

INSTRUMENTS

IN1– IN1+

IN2– IN2+

C1 R1

R2 R3 R4 C2

JP1

TPA112 MSOP EVM

Vdd GND

SLOP126

R7C4

R10

Vo1

GND

Vo2

33 µF – 1000 µF

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TP A112 MSOP Audio Power Amplifier Evaluation Module Parts List

3.5 TPA112 MSOP Audio Power Amplifier Evaluation Module Parts List

Table 3–1. TPA112 MSOP EVM Parts List

Ref. Description Size

C3, C6 Capacitor, 1 µF, +80%/

–20%, nonpolarized, SMD

C5 Capacitor, 10 µF, 6.3 V,

SMD

C1, C2, C4, C7

R1, R9, R4 – R7

R2, R3, R8, R10

U1 IC, TPA112, audio

U2 IC, TLV2211,

PCB1 PCB, TPA112 MSOP EVM 1 SLOP126

†

Due to the very small size of the MSOP IC package, the standard part number TPA112 is replaced with the code TIAAD

Capacitor, 0.1 µF, +80%/ –20%, nonpolarized, SMD

Resistor, 20 kΩ, 1/16 W, 5%, SMD

Resistor, 82 kΩ, 1/16 W, 5%, SMD

amplifier, 150 mW, 2-channel, SMD

single-supply operational amplifier, SMD

Terminal post headers 11 Sullins Digi-Key

0603 2 Murata

A 1 Panasonic

0603 4 Murata

0603 6 Panasonic

0603 4 Panasonic

MSOP-8 1 TI

SOT23 1 TI

EVM

Qty.

Manufacturer/

Part Number

GRM39-Y5V105Z10PT

ECS-TOJY106R

GRM39-Y5V104Z10PT

ERJ-3GSYJ203

ERJ-3GSYJ823

TPA112DGN

†

Vendor/Number

Newark

Digi-Key PCS1106CT-ND

Newark

Digi-Key P20KGCT-ND

Digi-Key P82KGCT-ND

S1022-36-ND

Details

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3-12

Details

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