Texas Instruments TPA0242 User Manual

TPA0242 Audio Power Amplifier Evaluation Module
User’s Guide
March 2000 Mixed-Signal Products
SLOU074
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.
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, 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.
Copyright 2000, Texas Instruments Incorporated
Related Documentation From Texas Instruments
J
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.
J
TPA0242 Stereo 2-W Audio Power Amplifier
SLOS287) This is the data sheet for the TPA0242 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
(literature number
Trademarks
TI is a trademark of Texas Instruments Incorporated.
Chapter Title—Attribute Reference
iii
iv
Running Title—Attribute Reference
Contents
1 Introduction 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Feature Highlights 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 TP A0242 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 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Details 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Precautions 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 The TPA0242 Audio Power Amplifier Evaluation Module 3-3. . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 TPA0242 Audio Amplifier IC 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Inputs and Gain 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.3 Differential Input 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.4 Depop Circuitry 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.5 BTL Operation 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.6 Single-Ended Operation 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform 3-8. . . . . . . . . . . . . . .
3.3.1 Installing and Removing EVM Boards 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 TPA0242 Module Jumper Settings and Switches 3-9. . . . . . . . . . . . . . . . . . . . . . . .
3.3.3 Signal Routing 3-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.4 Mute (Shutdown)/Mode 3-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.5 Power Requirements 3-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.6 Inputs and Outputs 3-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Using The TPA0242 EVM Stand-Alone 3-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.1 TPA0242 EVM Connected for BTL Output 3-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.2 TPA0242 EVM Connected for Single-Ended Output 3-17. . . . . . . . . . . . . . . . . . . . .
3.5 TPA0242 Audio Power Amplifier Evaluation Module Parts List 3-18. . . . . . . . . . . . . . . . . . .
Chapter Title—Attribute Reference
v
Running Title—Attribute Reference
Figures
1–1 The TI TPA0242 Audio Amplifier Evaluation Module 1-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 Quick Start Platform Map 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Module Preparation 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 Quick Start Module Map 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–1 The TI Plug-N-Play Audio Amplifier Evaluation Platform 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–2 TPA0242 EVM 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–3 TPA0242 EVM Schematic Diagram 3-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4 TPA0242 Amplifier IC 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–5 TPA0242 EVM Jumpers and Switches 3-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–6 Platform Signal Routing and Outputs 3-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–7 Mute/Mode and Polarity Control 3-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–8 Typical Headphone Plug 3-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–9 TPA0242 EVM Connected for Stereo BTL Output 3-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–10 TPA0242 EVM Connected for Stereo Single-Ended Output 3-17. . . . . . . . . . . . . . . . . . . . . . . .
T ables
2–1 Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA0242 2-1. . . . . . . . .
2–2 Typical TPA0242 EVM Jumper Settings 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 Platform Jumper and Switch Settings for the TPA0242 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–4 Typical TPA0242 EVM Jumper Settings 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–1 TPA0242 EVM BTL Volume Settings 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–2 Typical TPA0242 EVM Jumper Settings for BTL Stand-Alone 3-16. . . . . . . . . . . . . . . . . . . . . .
3–3 Typical TPA0242 EVM Jumper Settings for Single-Ended Stand-Alone 3-17. . . . . . . . . . . . . .
3–4 TPA0242 EVM Parts List 3-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vi
Chapter 1
Introduction
This chapter provides an overview of the Texas Instruments (TI) TPA0242 audio amplifier evaluation module (SLOP275). It includes a list of EVM features, a brief description of the module illustrated with a pictorial diagram, and a list of EVM specifications.
Topic Page
1.1 Feature Highlights 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Description 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3 TP A0242 EVM Specifications 1–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction
1-1
Feature Highlights
1.1 Feature Highlights
The TI TPA0242 audio amplifier evaluation module and the TI plug-n-play audio amplifier evaluation platform include the following features:
-
TPA0242 stereo 2-W audio power amplifier evaluation module
J
J
J
J
J
J
J
J
-
Quick and easy configuration with the TI plug-n-play audio amplifier evalu­ation platform
Internal depop circuitry to minimize transients in outputs Dual channel, bridge-tied load (BTL) or single-ended operation 2 W per channel output power into 3 at 5 V, BTL Low current consumption in shutdown mode (150 µA) Internal input MUX selects among two sets of stereo inputs DC voltage volume control from +20 dB to –40 dB, and a –85 dB mute Differential stereo inputs PC Beep input
J
Evaluation module is designed to simply plug into the platform, automatically making all signal, control, and power connections
J
Platform provides flexible power options
J
Jumpers on the platform select power and module control options
J
Switches on the platform route signals
J
Platform provides quick and easy audio input and output connections
-
Platform power options
J
External 5-V – 15-V DC VCC supply inputs
J
External regulated VDD supply input
J
Socket for on-board 5 V/3.3 V VDD voltage regulator EVM
J
Onboard overvoltage and reverse polarity power protection
-
Platform audio input and output connections
J
Left and right RCA phono jack inputs
J
Miniature stereo phone jack input
J
Left and right RCA phono jack outputs
1-2
J
Left and right compression speaker terminal outputs
J
Miniature stereo headphone jack output
Introduction
1.2 Description
The TPA0242 stereo 2-W audio power amplifier evaluation module is a complete, 2-watt per channel stereo audio power amplifier. It consists of the TI TPA0242 stereo 2-W audio power amplifier IC along with a small number of other parts mounted on a circuit board that measures approximately 2 1/4 inches by 1 1/2 inches (Figure 1–1).
Figure 1–1.The TI TPA0242 Audio Amplifier Evaluation Module
Description
R1 C1
C2
R2
VDD GND
+
C10
R3
R4
S2
C6
C5
C4
C3
C11
U1
C12
C7C8C9
+
C13
VDD GND
S3
S4
SLOP275
ROUT+
GND
ROUT–
HP/LINE
SE/BTL PCBEEP
TEXAS INSTRUMENTS
SHUTDOWN
LOUT–
GND
LOUT+
R HP GND R LINE–
SHUTDOWN
R IN+
S1
L IN+ L LINE–
GND L HP
TPA00242 EVM Board
Single in-line header pins extend from 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 TPA0242 evaluation module 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
1.3 TPA0242 EVM Specifications
Supply voltage range, V Supply current, I Continuous output power per channel, P Audio input voltage, V
Minimum load impedance, R
DD
hook up
.
DD
: 3- BTL, VDD=5 V 2 W. . . . . .
O
: HP input 5 Vpp max. . . . . . . . . . . . . . . . . . . . . . . . . .
I,
Line input 5 Vpp max. . . . . . . . . . . . . . . . . . . . . . . .
PC BEEP input 5 Vpp max. . . . . . . . . . . . . . . . . . . .
L
Introduction
4.5 V to 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 A max. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-3
1-4
Introduction
Chapter 2
Quick Start
The steps in this chapter can be followed to quickly prepare the TP A0242 audio amplifier EVM for use. Using the TPA0242 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 TPA0242 EVM and will cause the TPA0242 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 TPA0242
EVM JP6 JP7 JP8 S2 S3
P-N-P Platform Mode X Hi Note 2 U2–U4
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.
Table 2–2. Typical TPA0242 EVM Jumper Settings
EVM S3
TPA0242 OFF
Note: ON = Shunt installed
OFF = Open
Topic Page
2.1 Precautions 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Quick Start List for Platform 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Quick Start List for Stand-Alone 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 VCC power input connector J1, J2, and/or VDD power input connector J6 are correct. Overvoltage or reverse-polarity power applied to these terminals can open onboard soldered-in fuses and cause other damage to the platform, installed evaluation modules, and/or the power source.
Inserting or Removing EVM Boards Do not insert or remove EVM boards with power applied—damage
to the EVM board, the platform, or both may result.
Figure 2–1.Quick Start Platform Map
7b
Power
Input
Audio Input
7b
SOURCE
VCC
J1
In
+
DC
VCC(J1)
JP1
(J2)
JP2
AC/DC
Batt
JP3
VR1
F1
C1+
Off Pwr
1
13
On
ICC JP4
S1
7 b
SUPPLY
7 b
POWER
U6
F2
VR2
7a
DC
D4
AC/DC
In
J2
In
Right
J3
D3
D2
D1
LED1
VCC
R1
Signal Conditioning
Stereo
J4
9
In
U1
B1
Audio Power Amps
IDD
JP5
U3 U4
R2
U2
LED2
VDD
Out
J7
Right
J8
Out
In/Out
+– +– Right
VDD
J6
+
Power In/Out
10
Speaker Output
5
Headphone Output
Left
J5
In
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
ConditioningS2
GND
OnOff
TP1
U5
U2-U4
U5
HP
Source
HP(U5)
S3
R4
JP6
Polarity
Lo Hi
JP7
+ +
R3
Out
Mode Mute
Spk(U2-U4)
Out
JP8
Stereo
C3 C2
HP Out
Left
J9
Left
J10
R5
2-2
23 4
6
Quick Start
2.2 Quick Start List for Platform
Follow these steps when using the TP A0242 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 Figure 2–2, 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.
2) Install a TPA0242 module in platform socket U2, 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
5) Set jumper JP6 to select the
Mode
control input (causes the TP A0242 to
Hi.
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 headphone source switch S3 to U2–U4.
Table 2–3. Platform Jumper and Switch Settings for the TPA0242
EVM JP6 JP7 JP8 S2 S3
P-N-P Platform Mode X Hi Note 2 U2–U4
Notes: 1) X = Don’t care
ON
2) Set S2 to
-
Power supply
to
OFF
when signal conditioning board is installed in U1; set S2
when no signal conditioning board is installed.
OFF
and that the platform
7) Select and connect the power supply (ensure power supply is set to a) Connect an external regulated power supply set to 5 V to platform V
OFF
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. Connect a 7 V – 12 V power source to a platform VCC power input J1 or J2 and jumper the appropriate power input (see platform user’s
guide).
-
Inputs and outputs
8) Ensure that the audio signal source level is 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 speakers to left and right RCA jacks J7 and J9 or to stripped wire speaker connectors J8.
Quick Start
2-3
):
Quick Start List for Platform
-
Evaluation module preparations
Figure 2–2.Module Preparation
R HP GND R LINE–
SHUTDOWN
R IN+
S1
R1 C1
C2
14
L IN+ L LINE– GND L HP
TPA00242 EVM Board
R2
Table 2–4. Typical TPA0242 EVM Jumper Settings
EVM S3
TPA0242 OFF
Note: ON = Shunt installed, OFF = Open
11) To allow the module SE/BTL control input to switch the amplifier IC between single ended (SE) and bridge-tied load (BTL) output modes, set output mode jumper S3 to single-ended output mode regardless of the control input state, set jumper S3 to ON.
VDD GND
+
C10
R4
R3
S2
S3
U1
C13
S4
C11
C12
SLOP275
C6
C5
C4
C3
C7C8C9
+
VDD GND
OFF
. To keep the module amplifier IC in the
ROUT+
GND
ROUT–
HP/LINE
SE/BTL
PCBEEP
TEXAS INSTRUMENTS
SHUTDOWN
LOUT–
GND
LOUT+
13 12
11
12) To allow the module HP/LINE control input to switch the amplifier IC between using the HP pins and the LINE pins as the signal inputs, set the input mode jumper S3 to
OFF
. To keep the amplifier IC in the HP input
mode regardless of the control input state, set jumper S3 to ON.
-
Power Up
13) To allow the amplifier IC to switch from the LINE
inputs to the HP inputs when the output switches from BTL output mode to SE output mode and vice versa, set jumper S4 to ON. To allow the inputs and output modes to switch independently, set jumper S4 to
OFF
.
Platform LED2 should light indicating the presence of VDD, and the evaluation modules installed on the platform should begin operation.
14) Adjust the signal source level as needed.
2-4
Quick Start
2.3 Quick Start List for Stand-Alone
Follow these steps to use the TP A0242 EVM stand-alone or when connecting it into existing circuits or equipment. Connections to the TPA0242 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 2–3 and details appear in Chapter 3.
Figure 2–3.Quick Start Module Map
Quick Start List for Stand-Alone
R1 C1
C2
R2
VDD GND
+
C10
R3
R4
S2
C6
C5
C4
C3
C11
U1
C12
C7C8C9
+
C13
VDD GND
S3
S4
SLOP275
ROUT+
GND
ROUT–
HP/LINE
SE/BTL PCBEEP
TEXAS INSTRUMENTS
SHUTDOWN
LOUT–
GND
LOUT+
OFF.
8 7 6
R HP GND R LINE–
SHUTDOWN
R IN+
S1
9
L IN+ L LINE– GND L HP
TPA00242 EVM Board
-
Power supply
1) Ensure that all external power sources are set to
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 audio signal source level adjustments are set to minimum.
4) Connect the right (left) positive lead of the audio source to the module R LINE– (L LINE–) pins and the negative lead to the R IN+ (L IN+) pins. If using the headphone inputs, connect the positive audio source to the module R HP (L HP) and the negative lead to R IN+ (L IN+). The inputs can be used with a differential or single-ended audio source, but the headphone and line have common positive inputs.
5) Select output mode: a) For BTL output, connect a speaker to the module OUT+ and OUT–
pins of each channel, or
b) For single-ended output, connect a headphone or a speaker to the
module OUT+ and GND pins of each channel through a 33 µF to 1000 µF output-coupling capacitor (Figure 3–10).
Quick Start
2-5
Quick Start List for Stand-Alone
-
6) To allow the module SE/BTL control input to switch the amplifier IC
7) To allow the module HP/LINE control input to switch the amplifier IC
-
8) To allow the amplifier IC to switch from the LINE inputs to the HP inputs
Evaluation module preparations
between single ended (SE) and bridge-tied load (BTL) output modes, set output mode jumper S3 to
OFF
. To keep the module amplifier IC in the
single-ended output mode regardless of the control input state, set jumper
ON
S3 to
.
between using the HP pins and the LINE pins as the signal inputs, set the input mode jumper S3 to
OFF
. To keep the amplifier IC in the HP input
mode regardless of the control input state, set jumper S3 to ON.
Control inputs
when the output switches from BTL output mode to SE output mode and vice versa, set jumper S4 to ON. To allow the inputs and output modes to switch independently , set jumper S4 to
OFF
. Connect control lines to the
various module control input pins as needed: a) SE/BTL: A high selects the single-ended (SE) output mode; a low or
float selects the bridge-tied load (BTL) output mode.
b) SHUTDOWN: A low shuts down the amplifier IC on the module; a high
or float allows normal operation.
-
Power-up
9) Verify correct voltage and input polarity and set the external power supply to
ON.
The EVM should begin operation.
10) Adjust the signal source level as needed.
2-6
Quick Start
Chapter 3
Details
This chapter provides details on the TP A0242 IC, the evaluation module, and the steps in the Quick-Start List, additional application information, and a parts list for the TPA0242 evaluation module.
Topic Page
3.1 Precautions 3–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 The TP A0242 Audio Power Amplifier Evaluation Module 3–3. . . . . . . . .
3.3 Using the TPA0242 EVM With the Plug-N-Play
Evaluation Platform 3–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Using The TP A0242 EVM Stand-Alone 3–16. . . . . . . . . . . . . . . . . . . . . . . .
3.5 TP A0242 Audio Power Amplifier Evaluation Module Parts List 3–18. .
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
Power
Input
Audio Input
+
In
VCC
In
D4
AC/DC
J2
J1
In
In
In
1997
Right
Stereo
Left
SOURCE
INSTRUMENTS
JP2
DC
VCC(J1)
D3
JP1
AC/DC
(J2)
D2
Batt
D1
JP3
VR1
J3
Signal Conditioning
J4
J5
****CAUTION**** Do not insert or remove EVM boards with power
TEXAS
Plug-N-Play Audio Amplifier Evaluation Platform SLOP097 Rev. C.1
F1
LED1
VCC
applied
C1+
R1
U1
power input connector J1, J2, and/or VDD power
CC
On
Off Pwr
S1
ICC JP4
SUPPLY
B1
JP5
Audio Power Amps
S2
IDD
R2
U3 U4
U2
OnOff
Conditioning
HP(U5)
U2-U4
U5
HP
Source
S3
R4
GND
U5
TP1
POWER
U6
LED2
VDD
JP6
Polarity
Lo Hi
JP7
JP8
+
+
R3
J7
Right
Out
J8
+– +
Right
Out
Left
Out
Mode
Mute
Spk(U2-U4)
J9
Left
Out
Stereo
C3 C2
HP Out
F2
In/Out
VDD
J10
R5
VR2
DC Power In/Out
+
J6
Speaker Output
Headphone Output
3-2
Details
The TPA0242 Audio Power Amplifier Evaluation Module
3.2 The TPA0242 Audio Power Amplifier Evaluation Module
The TPA0242 audio power amplifier evaluation module is powered by a TPA0242 stereo power amplifier capable of delivering greater than 2 W of continuous power per channel into 3- loads. The amplifier IC can be operated in either the BTL or single-ended output mode. The evaluation module includes control inputs for shutdown, selection between two sets of stereo inputs, and switching between single-ended and bridge-tied load output modes.
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, the EVM can be wired directly into existing circuits and equipment when used stand­alone.
The module appears in Figure 3–2 and its schematic is shown in Figure 3–3.
Figure 3–2.TPA0242 EVM
R HP GND R LINE–
SHUTDOWN
R IN+
S1
L IN+ L LINE– GND L HP
TPA00242 EVM Board
R1 C1
C2
R2
VDD GND
+
C10
R4
R3
S2
C6
C5
C4
C3
C11
U1
C12
C7C8C9
+
C13
VDD GND
S3
S4
SLOP275
ROUT+
GND
ROUT–
HP/LINE
SE/BTL
PCBEEP
TEXAS INSTRUMENTS
SHUTDOWN
LOUT–
GND
LOUT+
Details
3-3
The TPA0242 Audio Power Amplifier Evaluation Module
Figure 3–3.TPA0242 EVM Schematic Diagram
HP/LINE
L OUT + L LINE –
L HP
V
DD
GND
R IN +
L OUT –
L IN +
V
DD
S3
S4
SE/BTL
C12
10 µF
C2
0.47 µF
0.47 µF
R2
50 k
CCW
C7
0.47 µF
C9
CW
0.47 µF
0.47 µF
C8
C12
TP1
10
12
11
1
2
3
4
5
6
7
8
9
LHPIN
PV
DD
TPA0242
SHUTDOWNVOLUME
V
DD
R4
R LINE –
SHUTDOWN
R OUT +
R HP
V
DD
GND
ROUT– SE/BTL
C3
V
C1
0.47 µF
S1
C10
10 µF
100 k
DD
24
GNDGND
RLINEINPCB ENABLE
ROUT+LOUT+
RHPINLLINEIN
PV
ROUT–LOUT–
SE/BTLLIN
PC–BEEPBYPASS
23
22
21
20
19
V
DD
18
DD
17
CLKRIN
47 nF
16
15
14
13
GNDGND
C11
0.47 µF
R1
100 k
SHUTDOWN
0.47 µF
C4
0.47 µFR30
C6
C5
0.1 µF
PCBEEP
S2
3.2.1 TPA0242 Audio Amplifier IC
The TPA0242 audio amplifier IC (Figure 3–4) is a CMOS device intended primarily for bridge-tied load (BTL) operation in battery-powered applications. It is supplied in a very small 24-pin TSSOP thermal surface-mount package and has been designed to operate from low supply voltages (between approximately 4.5 V and 5.5 V). Typical applications include portable computers and multimedia systems.
The IC includes two separate amplifier channels, each of which can operate in either the bridged-tied load (BTL) mode or the single-ended mode as selected by the SE/BTL selected and the two output lines of each channel operate as mirror images of each other for increased power. The speaker load is connected directly across OUT+ and OUT–, 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, the headphone inputs are automatically selected and the speaker load is connected between the OUT+ terminal, through an output coupling capacitor, to system ground. For more information, see the TPA0242 amplifier IC data sheet, TI literature number SLOS287.
pin. In the BTL mode, the line inputs are automatically
3-4
Details
Figure 3–4.TPA0242 Amplifier IC
L HP
The TPA0242 Audio Power Amplifier Evaluation Module
L IN
L LINE
PC BEEP
R LINE
R IN
R HP
PC BEEP
3.2.2 Inputs and Gain
Each channel has two separate signal inputs, are automatically selected with the output mode (SE/BTL). An input multi­plexor in the amplifier IC selects the HP inputs when the IC is in the SE output mode and the line inputs when in the BTL output mode.
VOLUME
CONTROL
MUX
MUX
HP/LINE
SE/BTL
VOLUME
line
and
headphone (HP
), that
Line and headphone inputs share common positive inputs. If using separate line and headphone inputs, R IN and L IN should be AC grounded through a capacitor. If using differential inputs, line and headphone inputs must be the same.
A third input, PC BEEP, is common to both channels. The TPA0242 IC monitors this input when operating in both the active and shutdown modes and automatically switches to this input when a signal is sensed. In computer applications, for example, this allows the normal audio signal (music, sounds, etc.) to be interrupted when there is a need to output a computer beep. When the beep signal ends, the IC switches back to the previous mode.
The PC BEEP input gain is approximately 1/4 V/V , and requires an input signal greater than 1 V peak-to-peak in order to detect the signal. Setting PCB ENABLE high forces the TPA0242 IC into the PC BEEP mode, regardless of the amplitude of the signal applied to the PC BEEP input.
Details
3-5
The TPA0242 Audio Power Amplifier Evaluation Module
BTL
BTL
BTL
Potentiometer R2 adjusts the gain of the internal preamp stage of the TP A0242 amplifier by adjusting the control voltage applied to the VOLUME terminal (pin
3) of the IC. Rotating the potentiometer slider clockwise decreases the applied control voltage, resulting in a higher volume. T able 3–1 shows the relationship between the control voltage applied to the VOLUME terminal and the effective amplifier gain. Headphone gain is reduced by 6 dB.
Table 3–1. TPA0242 EVM BTL Volume Settings
VOLUME (Pin 3)
FROM
(V)
0 0.15 20 1.28 1.39 –2 2.52 2.63 –24
0.15 0.28 18 1.39 1.5 –4 2.63 2.74 –26
0.28 0.39 16 1.5 1.62 –6 2.74 2.86 –28
0.39 0.5 14 1.62 1.73 –8 2.86 2.97 –30
0.5 0.61 12 1.73 1.84 –10 2.97 3.08 –32
0.61 0.73 10 1.84 1.95 –12 3.08 3.2 –34
0.73 0.84 8 1.95 2.07 –14 3.2 3.31 –36
0.84 0.95 6 2.07 2.18 –16 3.31 3.42 –38
0.95 1.06 4 2.18 2.29 –18 3.42 3.54 –40
1.06 1.17 2 2.29 2.41 –20 3.54 5 –85
1.17 1.28 0 2.41 2.52 –22
TO (V)
GAIN
(dB)
VOLUME (Pin 3)
FROM
(V)
TO (V)
GAIN
(dB)
VOLUME (Pin 3)
FROM
(V)
TO (V)
GAIN
(dB)
Since the overall gain of the amplifier is set by the internal preamp stage and not by the power amplifier stage, the TPA0242 maintains the same total harmonic distortion (THD) at even the highest gain settings.
3.2.3 Differential Input
The TP A0242 line inputs allow the use of a single-ended or dif ferential audio source. The differential input stage of the amplifier cancels any noise that appears on both input lines of a channel. To use the TPA0242 EVM with a differential source, connect the positive lead of the audio source to the R LINE– (L LINE–) input and the negative lead from the audio source to the R IN+ (L IN+) input. To use the TPA0242 with a single-ended source, ac-ground the R IN+ and L IN+ inputs and apply the audio signal to the R LINE– and L LINE– inputs. Line and headphone inputs share common positive inputs. If using separate line and headphone inputs, R IN+ and L IN+ should be ac-grounded. If using differential inputs, line and headphone inputs must be the same. In a single-ended input application, the R IN+ and L IN+ inputs should be ac grounded at the audio source instead of at the device inputs for best noise performance.
3-6
Details
3.2.4 Depop Circuitry
The TPA0242 amplifier IC contains internal circuitry to minimize the various transients that might appear at the output during the transition from power off or shutdown to normal operation, or when transitioning between the SE and BTL modes.
3.2.5 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 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.
3.2.6 Single-Ended Operation
For single-ended operation, the module SE/BTL control input pin must be held high. The speaker (or headphone) load is connected to the module OUT+ output pin through a coupling capacitor, and to platform/system ground. A 470 -µF electrolytic coupling capacitor is provided on the platform in the signal path to the headphone output jack for this purpose, and a control signal from the platform headphone jack can be routed to the module control input pin to switch the TPA0242 IC to the single-ended mode.
The TPA0242 Audio Power Amplifier Evaluation Module
NOT
to
In the single-ended mode, the amplifiers inside the TP A0242 IC that drive the OUT– lines do not operate and do not dissipate any power. The OUT– pins go into a high-impedance state and can be left connected or allowed to float.
Details
3-7
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3 Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform
The TP A0242 audio amplifier evaluation module was designed to be used with the TI plug-n-play audio amplifier evaluation platform. It simply plugs into socket U2.
The following paragraphs provide additional details for using the TPA0242 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 U2 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 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.
3-8
5) Lift the EVM off the platform.
Details
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3.2 TPA0242 Module Jumper Settings and Switches
The TP A0242 EVM is equipped with a pushbutton SPST switch and a jumper that acts as an SPST switch to allow module operation to be modified to suit various requirements. In the following discussion, setting a jumper to means that a shunt is installed across the two pins of the jumper. Setting a
OFF
jumper to
means that no shunt is installed on the jumper. See Figure 3.5.
In typical applications, some or all of the jumper functions are controlled by the system microcontroller or external logic.
Figure 3–5.TPA0242 EVM Jumpers and Switches
ON
HP/LINE
L OUT + L LINE –
L HP
V
DD
GND
R IN +
L OUT –
L IN +
V
DD
S3
S4
SE/BTL
C12
10 µF
C2
0.47 µF
0.47 µF
R2
50 k
CCW
C7
0.47 µF
C9
CW
0.47 µF
0.47 µF
C8
C12
TP1
10
12
V
DD
R4
R LINE –
SHUTDOWN
R OUT +
R HP
V
DD
GND
ROUT– SE/BTL
C3
V
C1
0.47 µF
S1
C10
10 µF
100 k
DD
1
LHPIN
PV
DD
TPA0242
RLINEINPCB ENABLE
SHUTDOWNVOLUME
ROUT+LOUT+
RHPINLLINEIN
PV
ROUT–LOUT–
SE/BTLLIN
PC–BEEPBYPASS
2
3
4
5
6
7
8
9
11
24
GNDGND
23
22
21
20
19
V
DD
18
DD
17
CLKRIN
47 nF
16
15
14
13
GNDGND
C11
0.47 µF
R1
100 k
SHUTDOWN
0.47 µF
C4
0.47 µFR30
C6
C5
0.1 µF
PCBEEP
S2
Details
3-9
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3.2.1 S1 — Shutdown Switch
Pushbutton switch S1 on the EVM allows the manual shutdown of the TPA0242 amplifier IC.
3.3.2.2 S3 — Output Mode Jumper
To keep the module amplifier IC in the single-ended output mode regardless of the module control input state, set jumper S3 to ON.
Jumper S3 connects the SE/BTL output mode control input pin on the amplifier IC directly to VDD, so that when S3 is ON, the IC is held in the single-ended output mode regardless of the state of the SE/BTL module control input. When S3 is OFF , a pulldown resistor on the module holds the IC output mode control input pin low, keeping the IC in the BTL output mode.
The TPA0242 amplifier IC has two separate inputs for each channel. An internal multiplexor selects which input will be connected to the amplifier based on the state of the SE/BTL
pin on the IC.
3.3.2.3 S3 — Input Mode Jumper
T o force the module amplifier IC to use the HP input regardless of the module control input state, set jumper S3 to ON.
Jumper S3 connects the HP/LINE input mode control pin on the amplifier IC directly to VDD, so that when S3 is ON, the IC is held in the HP input mode re­gardless of the state of the HP/LINE module control input. When S3 is OFF, a pulldown resistor on the module holds the IC input control mode input pin low, allowing the IC to use the LINE
3.3.2.4 S4 — Input and Output Mode Jumper
To force the module amplifier IC to use the HP input when in SE output mode and to use the LINE input when in BTL output mode, set jumper S4 to ON.
When jumper S4 is ON, the HP/LINE IC and the SE/BTL output mode control pin on the amplifier IC are shorted to­gether so that both the input and output multiplexors switch simultaneously. When S4 is OFF , the input and output modes may be switched independently of each other.
inputs as the source of an input signal.
input mode control pin on the amplifier
3-10
Details
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3.3 Signal Routing
Signal flow on the platform is controlled by two signal routing switches, as shown in Figure 3–6.
Figure 3–6.Platform Signal Routing and Outputs
Off
R
Audio
Input
L
U1
Signal
Conditioning
3.3.3.1 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 TPA0242.
-
Switch S2 selects signal conditioning or bypasses it.
S2
On
U2
TPA0242
Amplifier EVM
U5
Stereo
Headphone
Amplifier
+
GND
R
L
R
L
J7, J8, J9
Speaker
Outputs
– +
+ –
Headphone
Output
– +
J10
R
L
U2–U4
R
S3
L
U5
3.3.3.2 Headphone Output Jack
Switch S3 is the source select for the stereo headphone output jack, J10. The headphone jack is capacitively coupled (via 470 µF electrolytics) and can output either the signal from the headphone amplifier in socket U5, or the signal from the TPA0242 power amplifier installed in socket U2, 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 TP A0242 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 socket to shut down the TPA0242 EVM or switch it to single-ended output mode 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
T o keep the TP A0242 amplifier outputs separated, set switch S3 to the headphone amplifier position (U5) and use the speaker outputs (J7, J8, and J9)
J
T o route the TPA0242 amplifier outputs to the headphone output jack (J10), set switch S3 to the power amplifier position ( this setting connected to J10
U2 – U4)
only
if the TPA0242 EVM is to drive single-ended loads
— use
Details
3-1 1
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3.4 Mute (Shutdown)/Mode
The TP A0242 EVM is equipped with a shutdown control input pin. When this input is pulled to ground, the TP A0242 amplifier IC on the module enters the shutdown mode and dissipates very little power. While in the shutdown mode, the PC BEEP input is still active. When the EVM control input is tied to GND or allowed to float, normal 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 to conserve power.
A mode control input pin on the EVM switches the TPA0242 amplifier IC between the bridge-tied load (BTL) output mode and the single-ended (SE) 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 in the single-ended output mode.
In the typical application, output mode switching allows the TPA0242 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.
, the module operates
DD
3.3.4.1 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 3–7). Each control line is pulled down by a 1-k resistor to ground (R4 and R5). The switch in the headphone jack pulls one line or the other up to V 240- resistor (R3) depending on whether a plug is inserted in J10 or not.
Figure 3–7.Mute/Mode and Polarity Control
V
DD
R3 240
J10
Headphone
Jack
R4 1 k
R5 1 k
Polarity
JP8 JP6
Lo
Hi
SPK
(U2–U4)
Mode
Mute
through a
DD
U2
Power
Amplifier
3-12
Details
Using The TP A0242 EVM With the Plug-N-Play Evaluation Platform
3.3.4.2 Mute/Mode Select (JP6)
A 3-pin jumper header (JP6) on the platform, functioning as an SPDT switch, routes the control signal from the headphone jack to either the shutdown control input pin or the mode control input pin of the evaluation module.
J
To shut down the TPA0242 amplifier module using the control signal from the platform headphone jack, jumper JP6 to
J
T o switch the output mode of the TP A0242 amplifier between BTL and single-ended using the control signal from the platform headphone jack, jumper JP6 to
3.3.4.3 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 TP A0242:
J
To shut down the TPA0242 amplifier module into the headphone jack, jumper JP8 to
MODE
MUTE
when
a plug is inserted
Lo
(this is the typical setting).
J
To shut down the TPA0242 amplifier module
until
a plug is inserted
into the headphone jack, jumper JP8 to Hi.
-
When JP6 is set to Mode, use the following JP8 settings for the TP A0242:
J
To switch the TPA0242 amplifier module to the
single-ended
mode when a plug is inserted into the headphone jack, jumper JP8 to
Hi
(this is the typical setting).
J
T o switch the TP A0242 amplifier module to the
BTL
output mode when
a plug is inserted into the headphone jack, jumper JP8 to Lo.
output
Details
3-13
Power Requirements
3.3.5 Power Requirements
The TP A0242 audio power amplifier evaluation module can operate from any voltage between approximately 4.5 V and 5.5 V; however, the TPA0242 amplifier IC on the module is characterized for operation at 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 different voltage.
The TI plug-n-play audio amplifier evaluation platform with a voltage regulator EVM installed on it can provide a regulated V unregulated VCC voltage inputs between approximately 5.5 V and 12 V, including an onboard 9-V battery. Or , an external regulated power source can be used to supply V module installed on it.
Although the TPA0242 amplifier IC draws approximately 0.65 A from the power supply during continuous full power output, peak current draw can be as high as 1 A. Any power supply connected to the platform should be capable of providing 1 A of current to avoid clipping of the output signal during peaks. Current consumption driving speakers at normal listening levels is typically
0.3 A or less.
supply from a wide variety of
DD
voltage to the platform and the TPA0242 evaluation
DD
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 A0242 amplifier IC installed on the evaluation module (6 V) or damage to the IC may result. In no case should VDD 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.
V
DD
-
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 VCC voltage applied to the platform exceed 15 V, or the overvoltage protection circuit on the V
bus will trip.
CC
3-14
Details
3.3.6 Inputs and Outputs
The TI plug-n-play audio amplifier evaluation platform is equipped with several standard conectors for audio inputs and outputs.
3.3.6.1 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 TP A0242 EVM has a special PC BEEP signal input pin (TP2) on the top of the module PCB.
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.
3.3.6.2 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.
Inputs and Outputs
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 TP A0242 power amplifier EVM to operate in the highly-efficient bridge-tied load configuration when driving speakers.
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 3–6). When the TPA0242 output signal is routed to J10 by S3, signals output via J10 are returned to platform ground when a plug is inserted (Figure 3–8), requiring single-ended operation of the power amplifiers.
Figure 3–8.Typical Headphone Plug
Left Right GND
Details
3-15
Using The TPA0242 EVM Stand-Alone
3.4 Using The TPA0242 EVM Stand-Alone
Using the TPA0242 audio power amplifier evaluation module stand-alone is much the same as using it with the platform. The same 4.5-V to 5.5-V power supply range and the isolated OUT+ and OUT– lines for BTL operation requirement exists.
Note that the shutdown signal applied to the EVM SHUTDOWN able to supply enough current to overcome the pullup resistor on the module (100 kΩ).
3.4.1 TPA0242 EVM Connected for BTL Output
Figure 3–9.TPA0242 EVM Connected for Stereo BTL Output
C3
R1 C1
C2
R2
VDD GND
VDD GND
+
C10
R4
R3
C6
C5
C4
U1
C12
C7C8C9
+
C13
S2
C11
S3
S4
SLOP275
TEXAS INSTRUMENTS
Audio
Input
(Right)
Audio
Input (Left)
R HP GND R LINE–
SHUTDOWN
R IN+
S1
L IN+ L LINE–
GND L HP
TPA00242 EVM Board
ROUT+
GND
ROUT–
HP/LINE
SE/BTL PCBEEP
SHUTDOWN
LOUT–
GND
LOUT+
pin must be
Right
External Shut Down Control
(active low)
Left
5 V
Table 3–2. Typical TPA0242 EVM Jumper Settings for BTL Stand-Alone
EVM S3
TPA0242 OFF
Note: ON = Shunt installed
OFF = Open
3-16
Details
Using The TPA0242 EVM Stand-Alone
3.4.2 TPA0242 EVM Connected for Single-Ended Output
Figure 3–10. TPA0242 EVM Connected for Stereo Single-Ended Output
Audio
Input
(Right)
R HP GND R LINE– R IN+
SHUTDOWN
S1
R1 C1
C2
VDD GND
+
C10
R4
R3
C6
C5
C4
C3
U1
C12
S2
C11
ROUT+
GND
S3
S4
ROUT–
HP/LINE
SE/BTL PCBEEP
TEXAS INSTRUMENTS
+
33 µF – 1000 µF
Audio
Input
(Left)
L IN+ L LINE–
GND L HP
TPA00242 EVM Board
R2
VDD GND
C7C8C9
+
C13
SLOP275
SHUTDOWN
+
LOUT–
GND
LOUT+
5 V
Table 3–3. Typical TPA0242 EVM Jumper Settings for Single-Ended Stand-Alone
EVM S3
TPA0242 ON
Note: ON = Shunt installed
OFF = Open
33 µF – 1000 µF
Details
3-17
TP A0242 Audio Power Amplifier Evaluation Module Parts List
3.5 TPA0242 Audio Power Amplifier Evaluation Module Parts List
Table 3–4.TPA0242 EVM Parts List
Reference Description Size
C5 Capacitor, 0.1 µF, 10%,
nonpolarized
C1, C2, C3, C4, C7, C8, C9, C1 1, C12
C6 Capacitor, 0.47 nF,
C10, C13 Capacitor, 10 µF, 6.3 V A 2 Panasonic
R1, R4 Resistor, 100 k, 1/8 W,
R3 Resistor, 0 , 1/8 W 0805 1 Panasonic
R2 Potentiometer, 50 kΩ, ST
S1 Switch, momentary SMD 1 Panasonic
TP1, TP2 Test points, red 2 Farnell
Capacitor, 0.47 µF, 80%/–20%, nonpolarized
80%/–20%, nonpolarized
5%
SL, thru hole
0805 1 Murata
0805 9 Murata
0805 1
0805 2 Panasonic
EVM
Qty.
1 Bourns
Manufacturer/
Part Number
GRM40-X7R104K25
GRM40-Y5V474Z16
ECS-TOJY106R
ERJ-6GEYJ104V
ERJ-6GEYJ200V
3362P–1–503
P8050SCT-ND
240–345
Digi-Key Number
Digi-Key PCS1106CT-ND
Digi-Key P100KABK-ND
Digi-Key P02ABK-ND
Digi-Key 3362P–503–ND
Digi-Key P8050SCT-ND
S3 Header, 2 position 2 mm 1 Norcomp Digi-Key
2163S-02-ND
P3 Shunts 2 mm 1 2JM–G Digi-Key
SPE1302–ND
U1 IC, TPA0242, audio
amplifier, 1 W, 2 channel
PCB1 PCB, TPA0242 EVM 1 TI
24 pin
TSSOP
1 TI
TPA0242PWP
SLOP275
3-18
Details
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