Texas Instruments SLOU025 User Manual

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TPA122 MSOP Audio Power Amplifier Evaluation Module

User’s Guide

1998 Mixed-Signal Products

SLOU025

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 acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability.

TI warrants performance of its semiconductor products to the specifications 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.

CERT AIN 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, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO BE FULLY AT THE CUSTOMER’S RISK.

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 semiconductor 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, warranty or endorsement thereof.

Related Documentation From Texas Instruments

TI Plug-N-Play Audio Amplifier Evaluation Platform

number SLOU011) provides detailed information on the evaluation platform and its use with TI audio evaluation modules.

TP A122 150-mW STEREO AUDIO POWER AMPLIFIER

(literature number SLOS211) This is the data sheet for the TPA122 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

(literature

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 TPA122 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 TPA122 MSOP Audio Amplifier Evaluation Module 3-3. . . . . . . . . . . . . . . . . . . . . . . . . .

3.2.1 TPA122 Audio Amplifier IC 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2.2 Module Gain 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2.3 Shutdown 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3 Using The TPA122 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 Shutdown 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3.4 Power Requirements 3-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3.5 Inputs and Outputs 3-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4 Using The TPA122 MSOP EVM Stand-Alone 3-1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4.1 TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier 3-11. . . . . . .

3.5 TPA122 MSOP Audio Amplifier Evaluation Module Parts List 3-12. . . . . . . . . . . . . . . . . . . .

Chapter Title—Attribute Reference

Running Title—Attribute Reference

Figures

1–1 The TI TPA122 MSOP Audio Amplifier Evaluation Module 1-4. . . . . . . . . . . . . . . . . . . . . . . . . .

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 TPA122 MSOP EVM 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–3 TPA122 MSOP EVM Schematic Diagram 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–4 TPA122 Audio Amplifier IC 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–5 Platform Signal Routing and Outputs 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–6 Mute Polarity Control 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–7 Typical Headphone Plug 3-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–8 TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier 3-11. . . . . . . . . . . . . . . . .

T ables

2–1 Typical TI Plug-N-Play Platform Jumper and Switch Settings for the

2–2 Platform Jumper and Switch Settings for the TPA122 MSOP EVM 2-3. . . . . . . . . . . . . . . . . . .

3–1 TPA122 MSOP EVM Parts List 3-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TPA122 MSOP EVM 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 1

Introduction

This chapter provides an overview of the Texas Instruments (TI) TPA122 MSOP Audio Amplifier Evaluation Module (SLOP125). 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 A122 MSOP EVM Specifications 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction

1-1

Features

1.1 Features

The TI TPA122 MSOP Audio Amplifier Evaluation Module and the TI Plug-N-Play Audio Amplifier Evaluation Platform include the following features:

TPA122 MSOP Stereo Audio Power Amplifier Evaluation Module

Dual channel, single-ended operation

150-mW output power into 8 Ω at 5 V

2.5-V to 5.5-V operation

Very low distortion — THD+N is less than 0.006% @ 1 kHz and less than 0.07% from 20 Hz to 20 kHz into 10-kΩ loads; less than 0.02% @ 1 kHz and less than 0.4% from 20 Hz to 20 kHz into 32-Ω loads; and less than 0.05% @ 1 kHz and less than 0.8% from 20 Hz to 20 kHz into 8-Ω loads

Extremely low current consumption in shutdown mode

Internal thermal and short-circuit protection

Internal pop reduction circuitry

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 on-board 5-V VDD voltage regulator EVM

On-board overvoltage and reverse polarity power protection

Platform Audio Input and Output Connections

Left and right RCA phono jack inputs

1-2

Miniature stereo phone jack input

Left and right RCA phono jack outputs

Left and right compression speaker terminal outputs

Miniature stereo headphone jack output

Introduction

1.2 Description

The TP A122 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 TPA122 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 TPA122 Audio Amplifier Evaluation Module

Description

Shutdown

IN1 GND

TEXAS

INSTRUMENTS

IN2 GND

†

Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE

VDD GND

SLOP127

TPA122 MSOP EVM

Vo1

GND

†

GND

Vo2

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 single TPA122 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 TPA122 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Introduction

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

1-3

1-4

Introduction

Chapter 2

Quick Start

The steps in this chapter can be followed to quickly prepare the TP A122 MSOP audio amplifier EVM for use. Using the TPA122 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 TP A122 MSOP EVM and will cause the TPA122 IC to shut down/mute when a plug is removed from platform headphone jack J10.

Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the

TPA122 MSOP EVM

EVM JP6 JP7 JP8 S2 S3

TPA122 X Hi 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.

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

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.

Power

Input

Audio Input

Figure 2–1.

SOURCE

VCC

AC/DC

Right

Stereo

Left

1997

Quick Start Platform Map

JP3

JP2

JP1

VCC(J1)

AC/DC

(J2)

Batt

Signal Conditioning

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

TEXAS

INSTRUMENTS

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

VR1

LED1

VCC

applied

C1+

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

Stereo

VR2

In/Out

VDD

+–+– Right

Left

Headphone Output

J10

DC Power In/Out

Speaker Output

2-2

Quick Start

2.2 Quick Start List for Platform

Follow these steps when using the TPA122 MSOP EVM with the TI Plug-N-Play Audio Amplifier Evaluation Platform (see the platform user’s guide, SLOU01 1, for additional details). Numbered callouts for selected steps are shown in Figure 2–1 and details appear in Chapter 3.

Platform preparations

Quick Start List for Platform

1) Ensure that all external power sources are set to power switch S1 is set to

OFF.

OFF

and that the platform

2) Install a TP A122 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 control signal Polarity jumper JP7 to

Hi.

5) 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 TPA122 MSOP EVM

EVM JP6 JP7 JP8 S2 S3

TPA122 X Hi X Note 2 U5

Notes: 1) X = Don’t care

2) Set S2 to to

Power supply

6) 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 to observe marked polarity, or

OFF

when signal conditioning board is installed in U1; set S2

when no signal conditioning board is installed.

power input connector J6, taking care

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

7) Ensure that signal source level is set to minimum.

8) Connect the audio source to left and right RCA phono jacks J3 and J5 or stereo miniature phone jack J4.

9) Connect 32-Ω headphones to headphone jack J10.

Power up

10) Verify correct voltage and input polarity and set the external power supply to

ON.

If VCC 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 VDD, and the evaluation modules installed on the platform should begin operation.

11) 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 TPA122 MSOP EVM stand-alone or when connecting it into existing circuits or equipment. Connections to the TPA122 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.

†

Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE

Quick Start Module Map

IN1 GND

TEXAS

INSTRUMENTS

IN2 GND

Power supply

1) Ensure that all external power sources are set to

Shutdown

SLOP127

TPA122 MSOP EVM

VDD GND

†

Vo1

GND

Vo2

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.

2-4

Power-up

4) Connect the audio source to the module IN1, IN2, and GND pins, taking care to observe marked polarity.

5) Connect the Shutdown pin to V

6) Connect 32-Ω headphones to the module V

through a Normally Open switch.

1, VO2 pins through 33 µF

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

7) 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.

8) Verify correct voltage and input polarity and set the external power supply to

ON.

The EVM should begin operation.

9) Adjust the signal source level as needed.

Quick Start

Chapter 3

Details

This chapter provides details on the TPA122 IC, the evaluation module, the steps in the Quick-Start List, additional application information, and a parts list for the TPA122 MSOP evaluation module.

Topic Page

3.1 Precautions 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2 The TPA122 MSOP Audio Power Amplifier Evaluation Module 3–3. . . .

3.3 Using The TPA122 MSOP EVM With The Plug-N-Play

Evaluation Platform 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4 Using The TPA122 MSOP EVM Stand-Alone 3–11. . . . . . . . . . . . . . . . . . . .

3.5 TPA122 MSOP Audio Power Amplifier EVM Parts List 3–12. . . . . . . . . .

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

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 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

U3 U4

OnOff

ConditioningS2

SUPPLY

POWER

LED2

VDD

VR2

In/Out

VDD

Right

Out

+–+– Right

Out

Left

Out

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 TPA122 MSOP Audio Power Amplifier Evaluation Module

3.2 The TPA122 MSOP Audio Power Amplifier Evaluation Module

The TP A122 MSOP Audio Power Amplifier Evaluation Module is powered by a TP A122 150-mW Stereo Audio Amplifier IC. It includes a shutdown control signal input with onboard switch and can drive either line-level outputs, 32-Ω headphones, or 8-Ω speakers.

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.TPA122 MSOP EVM

Shutdown

IN1 GND

TEXAS

INSTRUMENTS

IN2 GND

†

Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE

VDD GND

SLOP127

TPA122 MSOP EVM

†

Vo1

GND

Vo2

Figure 3–3.TPA122 MSOP EVM Schematic Diagram

Shutdown

(VDD to

Shutdown)

Audio Input 1

Audio Input 2

1 µF

R1 20 kΩ

20 kΩ

R3 80 kΩ

1 µF

Vo1

IN 1

Bypass

GND

TPA122

MSOP

Shutdown

Vo2

IN 2

10 µF

R5 80 kΩ

1 µF

Vo1 V

2.5 to 5.5 V

GND

Vo2

Details

3-3

The TPA122 MSOP Audio Power Amplifier Evaluation Module

3.2.1 TPA122 Audio Amplifier IC

The TPA122 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 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 with low distortion. As a line-level driver, distortion levels (THD+N) are below 0.07% into 10-kΩ loads across the audio band (20 Hz to 20 kHz). As a headphone driver, distortion levels are below 0.4% into 32-Ω loads across the audio band. And as a speaker driver, distortion levels are below 0.8% 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, depop circuitry, and a common shutdown control (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 TPA122 amplifier IC data sheet, TI Literature Number SLOS21 1.

Figure 3–4.TPA122 Amplifier IC

Stereo Audio

Input

From System

Control

IN1

Bypass

Shutdown

IN2

–

Bias

Control

– +

VO1

VO2

RLR

Stereo

3-4

Details

3.2.2 Module Gain

The TPA122 MSOP Audio Power Amplifier Evaluation Module

The TP A122 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 (R2 and R4, Figure 3–3). Use the following equation to determine the value of R

Gain+–

The TP A122 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 TPA122 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 A122 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 A122 input, and the TPA122 gain should be kept as low as possible.

3.2.3 Shutdown

When the shutdown terminal of the TP A122 amplifier IC is taken high, the IC ceases operation and enters a very low power state (65 µA at V 10 µA at V

= 3.3 V Typ). This is accomplished by applying a control signal

= 5 V and

to the module SD 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 mute signal for the module either when a plug is plug is

removed

inserted

into the platform headphone output jack or when the

, as selected by a platform jumper (JP7).

Details

3-5

Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform

3.3 Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform

The TPA122 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 A122 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.

3-6

5) Lift the EVM off the platform.

Details

Using The TPA122 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

Audio

Input

Signal

Conditioning

Off

Mono Power

Amplifier EVM

Mono Power

Amplifier EVM

TPA122 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 A122 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 TPA122 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. A switch inside the headphone jack produces a control signal that can be routed to the headphone amplifier socket to shutdown the TP A122 MSOP EVM when the headphone plug is removed.

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

Details

3-7

Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform

3.3.3 Shutdown

The TP A122 MSOP EVM is equipped with a shutdown control input pin. When this input is tied to V operation and enters an ultra-low-power state. When the EVM shutdown 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 muted to conserve power.

3.3.3.1 Headphone Jack Control Signals

The platform headphone output jack (J10) contains an internal switch that changes the state of a pair of control lines when a plug is inserted or removed (Figure 3–6). 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 240 Ω resistor (R3), depending on whether or not a plug is inserted in J10.

, the TPA122 amplifier IC on the module ceases

Figure 3–6.Shutdown Polarity Control

R3 240 Ω

J10

Headphone

Jack

3.3.3.2 Shutdown Polarity Select (JP7)

A 3-pin jumper header (JP7) on the platform selects the shutdown control signal polarity by connecting either the active-high or the active-low line from the headphone jack to platform socket U5. The TPA122 MSOP EVM shuts down when V

To shut down the TPA122 MSOP amplifier module inserted into the headphone jack, jumper JP7 to

To shut down the TPA122 MSOP amplifier module inserted into the headphone jack, jumper JP7 to setting).

is applied to the module SD pin.

R4 1 kΩ

R5 1 kΩ

Polarity

(U5)

JP7

Shutdown

Headphone

Amplifier

when

a plug is

until

a plug is

(this is the typical

3-8

Details

3.3.4 Power Requirements

The TPA122 MSOP Audio Power Amplifier Evaluation Module can operate from a 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 from a wide variety of unregulated V

5.5 V and 12 V, including an onboard 9 -V battery. Or, an external regulated power source can be used to supply V TPA122 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 the absolute maximum rating for the TP A122 amplifier IC installed on the evaluation module (5.5 V), or damage to the IC may result. In no case should V to screw terminals J6 of the platform, or the power protection circuit on the V

VCC voltage applied to the platform 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

Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform

voltage between approximately 2.5 V and 5.5 V.

supply

voltage inputs between approximately

voltage to the platform and the

MUST NOT

voltage of the incorrect polarity or in excess of 6.1 V be applied

exceed

line will trip.

MUST NOT

voltage applied to the platform exceed

exceed the maximum

bus will trip.

Details

3-9

Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform

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

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.

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 TPA122 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 3–7).

Figure 3–7.Typical Headphone Plug

Left Right GND

3-10

Details

Using The TPA122 MSOP EVM Stand-Alone

3.4 Using The TPA122 MSOP EVM Stand-Alone

Using the TPA122 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.

Note that the shutdown signal applied to the EVM SD pin must be able to supply enough current to overcome the pulldown resistor on the module (20 kΩ).

3.4.1 TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier

Figure 3–8.TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier

5 VDC

Shutdown

Audio

Input

(Right)

Audio

Input (Left)

†

Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE

Shutdown

IN1 GND

TEXAS

INSTRUMENTS

IN2 GND

VDD GND

SLOP127

TPA122 MSOP EVM

†

GND

Vo2

Vo1

33 µF – 1000 µF

Details

3-11

TP A122 MSOP Audio Power Amplifier Evaluation Module Parts List

3.5 TPA122 MSOP Audio Power Amplifier Evaluation Module Parts List

Table 3–1. TPA122 MSOP EVM Parts List

Ref. Description Size

C1, C2, C3, C4

C5 Capacitor, 10 µF, 6.3 V,

R1, R2,R4Resistor, 20 kΩ, 1/16 W,

R3, R5 Resistor, 80 kΩ, 1/16 W,

S1 Switch, momentary SMD 1 Panasonic

U1 IC, TPA122, audio

PCB1 PCB, TPA122 MSOP EVM 1 SLOP127

†

Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE

Capacitor, 1 µF, 80%/–20%, nonpolarized, SMD

SMD

5%, SMD

amplifier, 150 mW, 2-channel, SMD

Terminal post headers 11 Sullins Digi-Key

0603 4 Murata

A 1 Panasonic

0603 3 Panasonic

0603 2 Panasonic

MSOP-8 1 TI

EVM

Qty.

Manufacturer/

Part Number

GRM39-Y5V105Z10PT

ECS-TOJY106R

ERJ-3GSYJ203

ERJ-3GSYJ803

P8048SCT-ND

TP A122DGN

†

Vendor/Number

Newark

Digi-Key PCS1106CT-ND

Digi-Key

Digi-Key P8048SCT-ND

S1022-36-ND

3-12

Details

Texas Instruments SLOU025 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual