Texas Instruments Audio Power Aplifier Evaluation Module TPA 311 User's Guide

TPA311

Audio Power Amplifier

Evaluation Module

User’s Guide

1998 Mixed-Signal Products

TPA311 Audio Power Amplifier

Evaluation Module

User’s Guide

SLOU013

February 1998

Printed on Recycled Paper

IMPORTANT NOTICE

Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any semiconductor product or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current.

TI warrants performance of its semiconductor products and related software 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.

Certain applications using semiconductor products may involve potential risks of death, personal injury, or severe property or environmental damage (“Critical Applications”).

TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED, OR

WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT APPLICATIONS, DEVICES

OR SYSTEMS OR OTHER CRITICAL APPLICATIONS.

Inclusion of TI products in such applications is understood to be fully at the risk of the customer.

Use of TI products in such applications requires the written approval of an appropriate TI officer.

Questions concerning potential risk applications should be directed to TI through a local SC sales office.

In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards should be provided by the customer to minimize inherent or procedural hazards.

TI assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or services described herein. Nor does TI warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used.

Copyright



1998, Texas Instruments Incorporated

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 TPA311 350-mW LOW-VOLTAGE AUDIO POWER AMPLIFIER

(literature number SLOS207) This is the data sheet for the TPA311 audio amplifier integrated circuit.

FCC Warning

This equipment is intended for use in a laboratory test environment only. It generates, uses, and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to subpart

J of part 15 of FCC rules, which are designed to provide reasonable protection against radio frequency interference. Operation of this equipment in other environments may cause interference with radio communications, in which case the user at his own expense will be required to take whatever measures may be required to correct this interference.

Trademarks

TI is a trademark of Texas Instruments Incorporated.

Chapter Title—Attribute Reference iii

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Do this. . .

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Report mistakes in this document or any other TI documentation

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† Texas Instruments Product Information Center iv

Running Title—Attribute Reference

Contents

1 Introduction

1.1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1

1-3

1.2

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.3

TPA311 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-4

1-4

2 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.1

Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-1

2-2

2.2

Quick Start List for Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3

Quick Start List for Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-3

2-4

3 Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.1

Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-1

3-2

3.2

The TPA311 Audio Amplifier Evaluation Module

3.2.1

TPA311 Audio Amplifier IC

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-3

3-4

3.2.2

BTL Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2.3

Single-Ended Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2.4

Module Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-4

3-5

3-5

3.2.5

Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3

Using The TPA311 EVM With The Plug-N-Play Evaluation Platform . . . . . . . . . . . . . . .

3-5

3-6

3.3.1

Installing and Removing EVM Boards

3.3.2

Signal Routing

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3.3

Mute/Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-6

3-7

3-8

3.3.4

Power Requirements

3.3.5

Inputs and Outputs

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-10

3-11

3.4

Using The TPA311 EVM Stand-ALone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

3.4.1

TPA311 EVM Connected for BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4.2

TPA311 EVM Connected for Single-Ended Output . . . . . . . . . . . . . . . . . . . . . .

3-12

3-13

3.5

TPA311 Audio Amplifier Evaluation Module Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Chapter Title—Attribute Reference v

vi

Running Title—Attribute Reference

Figures

1–1 The TI TPA311 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

2–1 Quick Start Platform Map

2–2 Quick Start Module Map

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-2

2-4

3–1 The TI Plug-N-Play Audio Amplifier Evaluation Platform

3–2 TPA311 EVM

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-2

3-3

3–3 TPA311 EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

3–4 TPA311 Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

3-4

3-7

3–6 Mute/Mode and Polarity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–7 Typical Headphone Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-8

3-11

3–8 TPA311 EVM Connected for Stereo BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

3–9 TPA311 EVM Connected for Stereo Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

Tables

2–1 Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA311

2–2 Platform Jumper and Switch Settings for the TPA311

. . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2-1

2-3

3–1 TPA311 EVM Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14

Chapter 1

Introduction

This chapter provides an overview of the Texas Instruments (TI



) TPA311

Audio Amplifier Evaluation Module (SLOP116). It includes a list of EVM features, a brief description of the module illustrated with a pictorial diagram, and a list of EVM specifications.

Topic

1.1

Feature Highlights

1.2

Description

1.3

TPA311 EVM Specifications

Page

1–3

1–4

1–4

Introduction 1-1

1-2 Introduction

Feature Highlights

1.1

Feature Highlights

The TI TPA311 Audio Amplifier Evaluation Module and the TI Plug-N-Play

Audio Amplifier Evaluation Platform include the following features:

TPA311 Low-Voltage Audio Power Amplifier Evaluation Module

J

J

J

J

J

J

Single channel, bridge-tied load (BTL) or single-ended operation

3.3-V and 5-V operation

350 mW output power into 8

Ω

at 5 V, BTL

Ultra-low current consumption in shutdown/mute mode

Internal thermal and short-circuit protection

Module gain adjustable between approximately 2 and 22

-

J

J

J

J

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

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

J

J

J

J

J

On-board 9-V battery

External 5-V – 15-V DC V

External regulated V

DD

CC

supply inputs

supply input

Socket for on-board 5 V/3.3 V V

DD

voltage regulator EVM

On-board overvoltage and reverse polarity power protection

Platform Audio Input and Output Connections

J

J

J

J

J

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

Introduction 1-3

Description

1.2

Description

The TPA311 Audio Power Amplifier Evaluation Module is a complete, lowpower single-channel audio power amplifier. It consists of the TI TPA311

350-mW Low-Voltage Audio Power Amplifier IC along with a small number of other parts mounted on a circuit board that is approximately one and a quarter inches square (Figure 1–1).

Figure 1–1. The TI TPA311 Audio Amplifier Evaluation Module

Shutdown

VDD GND

–3

C5

S1

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

Single in-line header pins are mounted to the underside of the module circuit board to allow the EVM to be plugged into the TI Plug-N-Play Audio Amplifier

Evaluation Platform, or to be wired directly into existing circuits and equipment when used stand-alone.

The platform has room for a pair of TPA311 evaluation modules and is a convenient vehicle for demonstrating TI’s audio power amplifier and related evaluation modules. The EVMs simply plug into the platform, which 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

TPA311 EVM Specifications

Supply voltage range, V

DD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 V to 5.5 V

Supply current, I

DD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Continuous output power, P

O

: 8-

Ω

BTL, V

DD

= 5 V:

32-

Ω

BTL, V

DD

= 5 V:

250 mA, max

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 mW

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 mW

Audio input voltage, V

I

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minimum load impedance, R

L

2 Vpp, max

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Ω

1-4 Introduction

Chapter 2

Quick Start

The steps in this chapter can be followed to quickly prepare the TPA311 audio amplifier EVM for use. While using the TPA311 with the TI Plug-N-Play Audio

Amplifier Evaluation Platform is a quick and easy way to connect power, signal and control inputs, and signal outputs to the EVM using standard connectors, the audio amplifier evaluation module can be used stand-alone by making connections directly to the module pins, and can be wired directly into existing circuits or equipment.

The platform switch and jumper settings shown in Table 2–1 are typical for the

TPA311 EVM and will cause the TPA311 to switch to single-ended output mode when a plug is inserted into platform headphone jack J10.

Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA311

EVM

TPA311

JP6

Mode

JP7

X

JP8

Hi

S2

Note 2

S3

X

Notes: 1) X = Don’t care

2) Set S2 to ON when signal conditioning board is installed in U1; set S2 to OFF when no signal conditioning board is installed.

Topic

2.1

Precautions

2.2

Quick Start List for Platform

2.3

Quick Start List for Stand-Alone

Page

2–2

2–3

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

CC

power input connector J1, J2, and/or V

DD

power input connector J6 are correct. Overvoltage or reverse-polarity power applied to these terminals can open on-board soldered-in fuses and cause other damage to the platform, installed evaluation modules, and/or the power source.

Inserting or Removing EVM Boards

Do not insert or remove EVM boards with power applied — damage to the EVM board, the platform, or both may result.

Power

Input

7b

Figure 2–1.

Quick Start Platform Map

7b 1 11

VR1

F1 C1+ ICC

JP4

Signal Conditioning

R1

Audio

Power

Amps

9

Audio

Input

****CAUTION****

Do not insert or remove

EVM boards with power applied

Plug-N-Play Audio Amplifier

Evaluation Platform

SLOP097 Rev. C.1

3 2

2-2

7b

R2

7b

DC

Power

In/Out

7a

Speaker

Output

10

6

R3

R4

Polarity

Lo

Mode

Mute

Hi

Stereo

HP Out

R5

4

Headphone

Output

5

Quick Start

Quick Start List for Platform

2.2

Quick Start List for Platform

-

Use the following steps when using the TPA311 EVM with the TI Plug-N-Play

Audio Amplifier Evaluation Platform (see the platform user’s guide, SLOU011, for additional details). Numbered callouts for selected steps are shown in

Figure 2–1 and details appear in Chapter 3.

Platform preparations

1) Ensure that all external power sources are set to OFF and that the platform power switch S1 is set to OFF

2) Install a TPA311 module in platform sockets U3 and U4 for stereo operation (or a module in either U3 or U4 for single channel operation), taking care to align the module pins correctly

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

4) Set control signal Polarity jumper JP8 to Hi

5) Set jumper JP6 to select the Mode control input (causes the TPA311 to switch to the single-ended output mode if a plug is inserted into platform headphone jack J10)

6) If the headphone Jack (J10) output will be used, set Hp source switch S3 to U2–U4.

Table 2–2. Platform Jumper and Switch Settings for the TPA311

-

-

-

EVM

TPA311

JP6

Mode

JP7

X

JP8

Hi

S2

Note 2

S3

X

Notes: 1) X = Don’t care

2) Set S2 to ON when signal conditioning board is installed in U1; set S2 to OFF when no signal conditioning board is installed.

Power supply

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

2.0 V and 5.5 V to platform V

DD

power input connector J6 taking care to observe marked polarity, or b) Install a voltage regulator EVM (SLVP097 or equiv.) in platform socket

U6. Install a 9-V battery in B1 or connect a 7 V – 12 V power source to a platform V

CC

power input J1 or J2 and jumper the appropriate power input (see platform user’s guide)

Inputs and outputs

8) Ensure that signal source level adjustments and EVM gain, R4, are set to minimum

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

10) Connect 8-

Ω

– 32-

Ω

speakers to left and right RCA jacks J7 and J9 or to stripped wire connectors J8

Power-up

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

CC

and an on-board regulator EVM are used to provide V

DD

, set platform power switch S1 to ON

Platform LED2 should light indicating the presence of V

DD modules installed on the platform should begin operation.

, and the evaluation

12) Adjust the signal source level and EVM gain level (R4) as needed

Quick Start 2-3

Quick Start List for Stand-Alone

2.3

Quick Start List for Stand-Alone

Use the following steps to use the TPA311 EVM stand-alone or when connecting it into existing circuits or equipment. Connections to the TPA311 module header pins can be made via individual sockets, wire-wrapping, or soldering to the pins, either on the top or the bottom of the module circuit board.

Numbered callouts for selected steps are shown in Figure 2–2 and details appear in Chapter 3.

Figure 2–2.

Quick Start Module Map

5

4

2

Shutdown

VDD GND

–3

C5

S1

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

6 7

Gain Adjust

Power supply

1) Ensure that all external power sources are set to OFF

-

2) Connect an external regulated power supply set to 5 V to the module VDD and GND pins taking care to observe marked polarity

Inputs and outputs

3) Ensure that signal source level adjustments and EVM gain (R4) are set to minimum

4) Connect the audio source to the module IN+ and GND pins taking care to observe marked polarity

-

5) Connect the Shutdown pin to V

DD

through a Normally Open switch

6) For BTL output, connect an 8-

Ω

– 32-

Ω

speaker to the module OUT+ and

OUT– pins, or

7) For single-ended output, connect a headphone or an 8-

Ω

– 32-

Ω

speaker to the module OUT+ and GND pins through a 33

µ

F to 1000

µ

F outputcoupling capacitor (figure 3–9)

Power-up

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

The EVM should begin operation.

9) Adjust the signal source level and EVM gain level (R4) as needed

2-4 Quick Start

Chapter 3

Details

This chapter provides details on the TPA311 IC, the evaluation module, and the steps in the Quick-Start List, additional application information, and a parts list for the TPA311 evaluation module.

Topic Page

3.1

Precautions

3.2

The TPA311 Audio Power Amplifier Evaluation Module

3.2.1 TPA311 Audio Amplifier IC

3.2.2 BTL Operation

3.2.3 Single-Ended Operation

3.2.4 Module Gain

3.2.5 Shutdown

3.3

Using The TPA311 EVM With The Plug-N-Play Evaluation Platform 3–6

3.3.1 Installing and Removing EVM Boards 3–6

3.3.2 Signal Routing

3.3.3 Mute/Mode

3.3.4 Power Requirements

3.3.5 Inputs and Outputs

3–7

3–8

3–10

3–11

3.4

Using The TPA311 EVM Stand-Alone

3.4.1 TPA311 EVM Connected for BTL Output

3.4.2 TPA311 EVM Connected for Single-Ended Output

3–12

3–12

3–13

3–2

3–3

3–4

3–4

3–5

3–5

3–5

3.5

TPA311 Audio Power Amplifier Evaluation Module Parts List 3–14

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

CC

power input connector J1, J2, and/or V

DD

power input connector J6 are correct. Overvoltage or reverse-polarity power applied to these terminals can open on-board soldered-in fuses and cause other damage to the platform, installed evaluation modules, and/or the power source.

Inserting or Removing EVM Boards

Do not insert or remove EVM boards with power applied — damage to the EVM board, the platform, or both may result.

Power

Input

Figure 3–1. The TI Plug-N-Play Audio Amplifier Evaluation Platform

VR1

F1 C1+

ICC

JP4

R2

Signal Conditioning

R1

Audio

Power

Amps

Audio

Input

****CAUTION****

Do not insert or remove

EVM boards with power applied

Plug-N-Play Audio Amplifier

Evaluation Platform

SLOP097 Rev. C.1

DC

Power

In/Out

Speaker

Output

R3

R4

Polarity

Lo

Hi

Mode

Mute

Stereo

HP Out

R5

Headphone

Output

3-2 Details

The TPA311 Audio Power Amplifier Evaluation Module

3.2

The TPA311 Audio Power Amplifier Evaluation Module

The TPA311 Audio Power Amplifier Evaluation Module is powered by a

TPA311 350-mW Low-Power Audio Amplifier IC and includes on-board gain adjustment, a shutdown control signal input with on-board switch, and can be operated in either the BTL or single-ended output mode.

The module can be used with the TI Plug-N-Play Audio Amplifier Evaluation

Platform (Figure 3 –1) or wired directly into circuits or equipment. The module has single in-line header connector pins mounted to the under side of the board. These pins allow the module to be plugged into the TI platform, which automatically makes all the signal input and output, power, and control connections to the module.

The module connection pins are on 0.1-inch centers to allow easy use with standard perf board and plug board-based prototyping systems, or to be wired directly into existing circuits and equipment when used stand-alone.

The module appears in Figure 3–2 and its schematic is shown in Figure 3 – 3.

Figure 3–2. TPA311 EVM

Shutdown

VDD GND

–3

S1

C5

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

Figure 3–3. TPA311 EVM Schematic Diagram

Shutdown

R1

20 k

Ω

SE/BTL

S1

C2

2.2

µ

F

No

1

Shutdown V

O –

2

Bypass GND

3

SE/BTL V

DD

4

In V

O +

7

6

5

8

VDD

2 V to 5.5 V

C5

10

µ

F

+

C3

2.2

µ

F

GND

C1

1 µ F

R5

100 k

Ω

Audio Input+

R3

20 k

Ω

C4

5 pF

GND

R2

20 k

Ω

R4

200 k

Ω

OUT–

GND

OUT+

Details 3-3


3.2.1

TPA311 Audio Amplifier IC

The TPA311 audio amplifier IC is a CMOS device intended primarily for bridge-tied load (BTL) operation in battery-powered applications. It is supplied in a very small surface-mount package and has been designed to operate from low supply voltages (between approximately 2 V and 5.5 V) and deliver up to approximately 350 mW into an 8-

Ω

, BTL (Figure 3 – 4). Typical applications include portable phones, toys, games, and similar hand-held audio applications.

Figure 3–4. TPA311 Amplifier IC

4

IN

VDD/2

_

+

6

VDD

5

VO+

2

Bypass

_

+

8

VO–

1

Shutdown

3

SE/BTL

Bias

Control

7

GND

The IC includes two separate internal amplifiers and can operate in either the bridged-tied load (BTL) mode or the single-ended mode as selected by the

SE/BTL pin. In the BTL mode, the two amplifiers operate 180

°

out-of-phase with each other for increased power. The speaker load is connected directly across V

O

+ and V

O

–, and neither line is connected to ground. BTL operation provides many benefits, including quadruple the output power of single-ended operation and no need for bulky output coupling capacitors. In the single-ended mode, one internal amplifier is turned off and the speaker load is connected between the V

O

+ terminal, through an output coupling capacitor, and system ground. For more information, see the TPA311 amplifier IC data sheet, TI Literature Number SLOS207.

3.2.2

BTL Operation

To operate in the bridge-tied load output mode, the module SE/BTL control input terminal must be held low. The module output signal from OUT+ must go through the speaker load and be returned directly to OUT–, and NOT to system ground. This requires that the OUT– line be isolated not only from system ground, but also from the OUT– lines of any other amplifiers in the system. The platform provides such isolated output lines from the amplifier EVM sockets directly to separate left and right speaker connectors.

3-4 Details


3.2.3

SIngle-Ended Operation

For single-ended operation, the module SE/BTL control input pin must be held high. The speaker (or headphone) load is connected to the module OUT+ output pin through a coupling capacitor, and to platform/system ground. A

470 -

µ

F electrolytic coupling capacitor is provided on the platform in the signal path to the headphone output jack for this purpose and a control signal from the platform headphone jack can be routed to the module control input pin to switch the TPA311 IC to the single-ended mode.

In the single-ended mode, the amplifier inside the TPA311 IC that drives the

OUT– line does not operate and does not dissipate any power. The OUT– pin goes into a high-impedance state and can be left connected or allowed to float.

3.2.4

Module Gain

The TPA311 evaluation module can be set for an overall gain of between 2 and

22 by adjustment of the the on-board gain control, R4. The TPA311 amplifier

IC, as most other amplifiers, exhibits its best distortion and noise performance at lower gain levels (see the TPA311 data sheet). Even so, the TPA311 at its highest gain setting has significantly less distortion than most low-cost speakers.

Gain versus total harmonic distortion (THD) should be considered in each application. Both the module input signal level and the TPA311 module gain should be adjusted to obtain the lowest overall distortion level for a particular overall gain. A quick rule of thumb (everything else being equal): the module input signal level should be as high as possible without clipping or overloading the TPA311 input, and the TPA311 gain kept as low as possible.

3.2.5

Shutdown

When the shutdown terminal of the TPA311 amplifier IC is taken high, the IC ceases operation and enters an ultra-low power state. This is accomplished by applying a control signal to the module Shutdown pin or by pressing the

Shutdown switch, S1, on the module. When the control signal goes low or is removed (or the switch is released), amplifier operation resumes.

The Plug-N-Play platform can generate the shutdown (mute) signal for the module either when a plug is inserted into the platform headphone output jack or when the plug is removed, as selected by a platform jumper (JP8).

Details 3-5

Using The TPA311 EVM With the Plug-N-Play Evaluation Platform

3.3

Using The TPA311 EVM With the Plug-N-Play Evaluation Platform

The TPA311 Audio Amplifier Evaluation Module was designed to be used with the TI Plug-N-Play Audio Amplifier Evaluation Platform. It simply plugs into socket U3 or U4.

The following paragraphs provide additional details for using the TPA311 EVM with the platform.

3.3.1

Installing and Removing EVM Boards

TI Plug-N-Play evaluation modules use single-in-line header pins installed on the underside of the module circuit board to plug into sockets on the platform.

The EVM pins and the platform sockets are keyed such that only the correct type of EVM can be installed in a particular socket, and then only with the proper orientation.

Evaluation modules are easily removed from the platform by simply prying them up and lifting them out of their sockets. Care must be taken, however, to prevent bending the pins.

3.3.1.1

EVM Insertion

1) Remove all power from the evaluation platform

2) Locate socket U3 or U4 on the platform

3) Orient the module correctly

4) Carefully align the pins of the module with the socket pin receptacles

5) Gently press the module into place

6) Check to be sure that all pins are seated properly and that none are bent over

3.3.1.2

EVM Removal

1) Remove all power from the evaluation platform

2) Using an appropriate tool as a lever, gently pry up one side of the module a small amount

3) Change to the opposite side of the module and use the tool to pry that side up a small amount

4) Alternate between sides, prying the module up a little more each time to avoid bending the pins, until it comes loose from the socket

5) Lift the EVM off of the platform

3-6 Details


3.3.2

Signal Routing

Signal flow on the platform is controlled by two signal routing switches, as shown in Figure 3 – 5.

Figure 3–5. Platform Signal Routing and Outputs

Off

R

U3

TPA311

Amplifier EVM

Audio

Input

U1

Signal

Conditioning

S2

U4

TPA311

Amplifier EVM

L On

U5

Stereo

Headphone

Amplifier

R

L

R

L

R

+

–

J7, J8, J9

Speaker

Outputs

L

–

+

U2 – U4

S3

GND

R

+

–

–

+

J10

Headphone

Output

L

U5

3.3.2.1

Signal Conditioning

The audio signal from the input jacks can be applied to the signal conditioning socket (U1) if an EVM is installed there, or socket U1 can be bypassed and the audio input signal applied directly to the inputs of the TPA311 power amplifiers.

Switch S2 selects signal conditioning or bypasses it

3.3.2.2

Headphone Output Jack

Switch S3 is the source select for the stereo headphone output jack, J10. The headphone jack is capacitively coupled (via 470

µ

F electrolytics) and can output either the signal from the headphone amplifier in socket U5, or the signal from the TPA311 power amplifiers installed in sockets U3 and U4, as determined by the setting of headphone source select switch S3.

When S3 is set to the power amplifier position (U2 – U4), the headphone jack is connected to the TP311 power amplifier OUT+ output lines. When a plug is inserted into the jack, signals output through J10 are returned to platform ground, requiring single-ended power amplifier operation. A switch inside the headphone jack produces a control signal that can be routed to the power amplifier sockets to shut down the TPA311 EVMs when a plug is inserted.

Source select switch S3 connects the headphone jack to the output lines of either the headphone amplifier socket U5, or the power amplifier sockets

(U2 – U4).

J To keep the TPA311 amplifier outputs separated, set switch S3 to the headphone amplifier position ( U5 ) and use the speaker outputs (J7,

J8, and J9)

J To route the TPA311 amplifier outputs to the headphone output jack

(J10), set switch S3 to the power amplifier position ( U2 – U4 ) — use this setting only if the TPA311 EVMs are to drive single-ended loads connected to J10

Details 3-7


3.3.3

Mute/Mode

The TPA311 EVM is equipped with a mute (shutdown) control input pin. When this input is tied to V

DD

, the TPA311 amplifier IC on the module shuts down and assumes an ultra-low power mode. When the EVM control input is tied to GND or allowed to float, amplifier operation resumes.

In typical applications, as often found in notebook computers, portable audio products, and such, the internal speakers mute when headphones are plugged into the headphone jack, or internal speakers mute when external speakers are connected. In applications using separate speaker and headphone amplifiers, the one not being used can be shut down (muted) to conserve power.

A mode control input pin on the EVM switches the TPA311 amplifier IC between the bridge-tied load (BTL) output mode and the single-ended output mode. When the mode control input is tied to GND, the module operates in the

BTL output mode. When this input is tied to V

DD

, the module operates in the single-ended output mode.

In the typical application, output mode switching allows the TPA311 to operate in the BTL output mode for increased power to internal speakers and then switch to single-ended mode to drive headphones when a plug is inserted into the headphone jack.

3.3.3.1

Headphone Jack Control Signals

The platform headphone output jack (J10) contains an internal switch that changes the state of a pair of control lines when a plug is inserted (Figure 3 – 6).

Each control line is pulled down by a 1-k

Ω

resistor to ground (R4 and R5). The switch in the headphone jack pulls one line or the other up to V

DD

through a

240

Ω

resistor (R3) depending on whether a plug is inserted in J10 or not.

Figure 3–6. Mute/Mode and Polarity Control

VDD

R3

240

Ω

J10

Headphone

Jack

R4

1 k

Ω

Lo

Polarity

JP8

R5

1 k

Ω

Hi

SPK

(U2–U4)

JP6

Mode

Mute

U3, U4

Power

Amplifiers

3-8 Details


3.3.3.2

Mute/Mode Select (JP6)

A 3-pin jumper header (JP6) on the platform, functioning as a SPDT switch, routes the control signal from the headphone jack to either the mute control input pin or the mode control input pin of the evaluation module.

J To mute the TPA311 amplifier module using the control signal from the platform headphone jack, jumper JP6 to MUTE

J To switch the output mode of the TPA311 amplifier between BTL and single-ended using the control signal from the platform headphone jack, jumper JP6 to MODE

3.3.3.3

Mute/Mode Polarity Select (JP8)

A second 3-pin jumper header (JP8) on the platform selects the control signal polarity by connecting either the active-high or the active-low line from the headphone jack to jumper JP6.

When JP6 is set to Mute, use the following JP8 settings for the TPA311:

J To mute the TPA311 amplifier module when a plug is inserted into the headphone jack, jumper JP8 to Hi (this is the typical setting).

J To mute the TPA311 amplifier module headphone jack, jumper JP8 to Lo.

until a plug is inserted into the

When JP6 is set to Mode, use the following JP8 settings for the TPA311:

J To switch the TPA311 amplifier module to the single-ended output mode when a plug is inserted into the headphone jack, jumper JP8 to

Hi (this is the typical setting).

J To switch the TPA311 amplifier module to the BTL output mode when a plug is inserted into the headphone jack, jumper JP8 to Lo.

Details 3-9

Power Requirements

3.3.4

Power Requirements

The TPA311 Audio Power Amplifier Evaluation Module can operate from any voltage between approximately 2 V and 5.5 V, however, the TPA311 amplifier

IC on the module is characterized for operation at 3.3 V and 5 V. For best performance (highest output power with lowest distortion), the module should be operated at approximately 5 V unless there is a specific reason for operating it from a lower voltage.

The TI Plug-N-Play Audio Amplifier Evaluation Platform with a voltage regulator EVM installed on it can provide a regulated V

DD

supply from a wide variety of unregulated V

CC

voltage inputs between approximately 5.5 V and

12 V, including an on-board 9 -V battery. Or, an external regulated power source can be used to supply V

DD

voltage to the platform and the TPA311 evaluation modules installed on it.

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

V

DD

voltage applied to platform screw terminals J6 MUST NOT exceed the absolute maximum rating for the TPA311 amplifier IC installed on the evaluation module (6 V) or damage to the IC may result. In no case should

V

DD

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

V

DD

line will trip.

V

CC

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

CC

voltage applied to the platform exceed

15 V, or the overvoltage protection circuit on the V

CC

bus will trip.

3-10 Details

Inputs and Outputs

3.3.5

Inputs and Outputs

The TI Plug-N-Play Audio Amplifier Evaluation Platform is equipped with several standard conectors for audio inputs and outputs.

3.3.5.1

Inputs

In most cases, audio signals enter the platform through either a pair of RCA phono jacks (J3 and J5) or a miniature (1/8

″

) stereo phone jack (J4). Certain signal conditioning and amplifier EVMs, however, may have additional signal input connectors mounted on the module circuit board.

The platform audio signal input jacks (J3, J4, and J5) are of the closed-circuit type, grounding the signal input lines when no plugs are inserted.

3.3.5.2

Outputs

Amplified audio output signals leave the platform through left and right RCA phono jacks (J7 and J9), left and right pairs of compression connectors for stripped speaker wires (J8), and optionally, through a miniature (1/8

″

) stereo phone jack (J10), for headphones.

The audio output lines from the power amplifiers are separate all the way to the edge of the platform (output jacks J7, J8, and J9) — the OUT– lines from the power amplifier sockets are not tied to each other or to platform ground.

This allows the TPA311 power amplifier EVMs to operate in the highly-efficient bridge-tied load configuration.

The headphone jack (J10) is capacitively coupled to source select switch S3, which connects J10 to the output lines of either the headphone amplifier socket or the power amplifier sockets (Figure 3 – 5). When the TPA311 output signal is routed to J10 by S3, signals output via J10 are returned to platform ground when a plug is inserted (Figure 3 – 7), requiring single-ended operation of the power amplifiers.

Figure 3–7. Typical Headphone Plug

Left Right GND

Details 3-11

Using The TPA311 EVM Stand-Alone

3.4

Using The TPA311 EVM Stand-Alone

Using the TPA311 Audio Power Amplifier Evaluation Module stand-alone is much the same as using it with the platform. The same 2-V to 5.5-V power supply range and the isolated OUT+ and OUT– lines for BTL operation requirement exists.

Note that the mute signal applied to the EVM shutdown pins must be able to supply enough current to overcome the pulldown resistors on the modules

(20 k

Ω

|| 20 k

Ω

for two EVMs).

3.4.1

TPA311 EVM Connected for BTL Output

Figure 3–8. TPA311 EVM Connected for Stereo BTL Output

5 VDC

Audio

Input

(Right)

External Mute

Control

(active high)

Audio

Input

(Left)

Shutdown

VDD GND

–3

S1

C5

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

Shutdown

5 VDC

VDD GND

GND

–3

S1

C5

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

Right

Left

Note: The SE/BTL* (SE/BTL) EVM pin is pulled to GND through a 100-K

Ω

resistor on the module.

3-12 Details

3.4.2

TPA311 EVM Connected for Single-Ended Output

Using The TPA311 EVM Stand-Alone

Figure 3–9. TPA311 EVM Connected for Stereo Single-Ended Output

5 VDC

Audio

Input

(Right)

External Mute

Control

(active high)

Audio

Input

(Left)

Shutdown

VDD GND

–3

C5

S1

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

Shutdown

5 VDC GND

VDD GND

–3

C5

S1

R1

C2

R5

C4

SE\BTL*

R2

IN+

C1

GND

R4

TPA311

R3

C3

U1

009227

OUT–

GND

OUT+

Literature #

SLOP116

EVM

+ 33

µ

F –

1000

µ

F

+

33

µ

F –

1000

µ

F

Details 3-13

TPA311 Audio Power Amplifier Evaluation Module Parts List

3.5

TPA311 Audio Power Amplifier Evaluation Module Parts List

Table 3–1. TPA311 EVM Parts List

R4

C5

Ref.

Description

Trim Pot, 200 k

Ω

Cermet

ST SL, (through hole)

Capacitor, 10

µ

F, 6.3 V

Size

EVM

Qty.

Manufacturer/

Part Number

1 Bourns

3323P-1-204

A 1 Panasonic

ECS-TOJY106R

1206 1 Murata

GRM42-6Y5V105Z16BL

C1

C2, C3 Capacitor, 2.2

µ

F, 20%, nonpolarized

C4

R1, R2,

R3

S1

U1

PCB1

Capacitor, 1

µ

F,

+80%/–20%, nonpolarized

Capacitor, 5 pF

Resistor, 20 k

5%

Ω

, 1/8 W,

Switch, momentary

IC, TPA311, audio amplifier, 350 mW, mono

PCB, TPA311 sample

EVM

1206 2 TDK

C3216X5R1A225

0805 1 Panasonic

ECU-V1H050CCN

1206 3 Panasonic

ERJ-8GEYJ203

SOIC

-8

1 Panasonic

P8048SCT-ND

1 TI

TPA311

1

NOTE: All items are SMD except as noted.

Digi-Key Number

Digi-Key

3323P-204-ND

Digi-Key

PCS1106CT-ND

Newark

93F2254

Digi-Key

PCC050CNCT-ND

Digi-Key

P20KECT-ND

Digi-Key

P8048SCT-ND

3-14 Details

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