Texas Instruments Music Mixer TPA0242 User Manual

User’s Guide  
March 2000  
Mixed-Signal Products  
SLOU074  
 
Preface  
Related Documentation From Texas Instruments  
TI Plug-N-Play Audio Amplifier Evaluation Platform (literature  
number SLOU011) provides detailed information on the evaluation  
platform and its use with TI audio evaluation modules.  
TPA0242 Stereo 2-W Audio Power Amplifier (literature number  
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.  
Trademarks  
TI is a trademark of Texas Instruments Incorporated.  
iii  
 
iv  
 
Contents  
1
2
3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1  
1.1  
1.2  
1.3  
Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2  
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3  
TPA0242 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3  
Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1  
2.1  
2.2  
2.3  
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2  
Quick Start List for Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3  
Quick Start List for Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5  
Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1  
3.1  
3.2  
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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  
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  
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  
TPA0242 Audio Power Amplifier Evaluation Module Parts List . . . . . . . . . . . . . . . . . . . 3-18  
3.3  
3.4  
3.5  
v
 
Figures  
1–1  
2–1  
2–2  
2–3  
3–1  
3–2  
3–3  
3–4  
3–5  
3–6  
3–7  
3–8  
3–9  
The TI TPA0242 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3  
Quick Start Platform Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2  
Module Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4  
Quick Start Module Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5  
The TI Plug-N-Play Audio Amplifier Evaluation Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2  
TPA0242 EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3  
TPA0242 EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4  
TPA0242 Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5  
TPA0242 EVM Jumpers and Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9  
Platform Signal Routing and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11  
Mute/Mode and Polarity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12  
Typical Headphone Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15  
TPA0242 EVM Connected for Stereo BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16  
3–10 TPA0242 EVM Connected for Stereo Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . . . 3-17  
Tables  
2–1  
2–2  
2–3  
2–4  
3–1  
3–2  
3–3  
3–4  
Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA0242 . . . . . . . . . 2-1  
Typical TPA0242 EVM Jumper Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1  
Platform Jumper and Switch Settings for the TPA0242 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3  
Typical TPA0242 EVM Jumper Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4  
TPA0242 EVM BTL Volume Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6  
Typical TPA0242 EVM Jumper Settings for BTL Stand-Alone . . . . . . . . . . . . . . . . . . . . . . 3-16  
Typical TPA0242 EVM Jumper Settings for Single-Ended Stand-Alone . . . . . . . . . . . . . . 3-17  
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 TPA0242 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–3  
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  
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  
Quick and easy configuration with the TI plug-n-play audio amplifier evalu-  
ation platform  
Evaluation module is designed to simply plug into the platform,  
automatically making all signal, control, and power connections  
Platform provides flexible power options  
Jumpers on the platform select power and module control options  
Switches on the platform route signals  
Platform provides quick and easy audio input and output connections  
Platform power options  
External 5-V – 15-V DC V  
supply inputs  
CC  
External regulated V  
supply input  
DD  
Socket for on-board 5 V/3.3 V V  
voltage regulator EVM  
DD  
Onboard overvoltage and reverse polarity power protection  
Platform audio input and output connections  
Left and right RCA phono jack inputs  
Miniature stereo phone jack input  
Left and right RCA phono jack outputs  
Left and right compression speaker terminal outputs  
Miniature stereo headphone jack output  
1-2  
Introduction  
 
Description  
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  
VDD  
GND  
C10  
R HP  
ROUT+  
GND  
+
GND  
ROUT–  
R LINE–  
SHUTDOWN  
R IN+  
HP/LINE  
SE/BTL  
S1  
R1  
C11  
PCBEEP  
C1  
C2  
U1  
TEXAS  
INSTRUMENTS  
R2  
SHUTDOWN  
L IN+  
L LINE–  
LOUT–  
GND  
GND  
L HP  
+
C13  
SLOP275  
LOUT+  
VDD  
GND  
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 auto-  
matically provides power to the modules, interconnects them correctly, and  
connectsthemtoaversatilearrayofstandardaudioinputandoutputjacksand  
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 TPA0242 EVM Specifications  
Supply voltage range, V  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 V to 5.5 V  
DD  
Supply current, I  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 A max  
DD  
Continuous output power per channel, P : 3-BTL, V =5 V . . . . . . 2 W  
O
DD  
Audio input voltage, V : HP input . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Vpp max  
I,  
Line input . . . . . . . . . . . . . . . . . . . . . . . . 5 Vpp max  
PC BEEP input . . . . . . . . . . . . . . . . . . . . 5 Vpp max  
Minimum load impedance, R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Ω  
L
1-3  
Introduction  
 
1-4  
Introduction  
 
Chapter 2  
Quick Start  
ThestepsinthischaptercanbefollowedtoquicklypreparetheTPA0242audio  
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 Table 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  
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  
power input connector J1, J2, and/or V  
power  
CC  
DD  
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  
1
13  
7
b
7
b
ICC  
JP4  
C1+  
F1  
VR1  
7a  
DC  
Power  
In/Out  
7b  
Power  
Input  
R2  
R1  
Audio  
Power  
Amps  
Signal Conditioning  
9
10  
Audio  
Input  
Speaker  
Output  
Mode  
Mute  
5
Polarity  
Lo  
****CAUTION****  
Do not insert or remove  
EVM boards with power  
applied  
Hi  
Stereo  
Headphone  
Output  
Plug-N-Play Audio Amplifier  
Evaluation Platform  
SLOP097 Rev. C.1  
R3  
R4  
HP Out  
R5  
3
2
6
4
2-2  
Quick Start  
 
Quick Start List for Platform  
2.2 Quick Start List for Platform  
FollowthesestepswhenusingtheTPA0242EVMwiththeTIplug-n-playaudio  
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  
1) EnsurethatallexternalpowersourcesaresettoOFF andthattheplatform  
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 Hi.  
5) Set jumper JP6 to select the Mode control input (causes the TPA0242 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 headphone source  
switch S3 to U2U4.  
Table 2–3. Platform Jumper and Switch Settings for the TPA0242  
EVM  
P-N-P Platform  
JP6  
Mode  
JP7  
JP8  
Hi  
S2  
S3  
X
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.  
Power supply  
7) Selectand connect the power supply (ensure power supply is set to OFF ):  
a) Connectanexternalregulatedpowersupplysetto5VtoplatformV  
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 V power input  
CC  
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.  
2-3  
Quick Start  
 
Quick Start List for Platform  
Evaluation module preparations  
Figure 2–2. Module Preparation  
VDD  
GND  
C10  
R HP  
GND  
ROUT+  
GND  
+
ROUT–  
R LINE–  
SHUTDOWN  
HP/LINE  
SE/BTL  
R IN+  
S1  
13  
12  
11  
R1  
C11  
U1  
PCBEEP  
C1  
C2  
TEXAS  
INSTRUMENTS  
14  
R2  
SHUTDOWN  
L IN+  
L LINE–  
LOUT–  
GND  
GND  
L HP  
+
C13  
GND  
SLOP275  
LOUT+  
VDD  
TPA00242 EVM Board  
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 OFF. To keep the module amplifier IC in the  
single-ended output mode regardless of the control input state, set jumper  
S3 to ON.  
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 V , and the evaluation  
DD  
modules installed on the platform should begin operation.  
14) Adjust the signal source level as needed.  
2-4  
Quick Start  
 
Quick Start List for Stand-Alone  
2.3 Quick Start List for Stand-Alone  
Follow these steps to use the TPA0242 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  
VDD  
GND  
C10  
R HP  
GND  
ROUT+  
GND  
+
ROUT–  
R LINE–  
SHUTDOWN  
HP/LINE  
SE/BTL  
R IN+  
S1  
8
7
6
R1  
C11  
U1  
PCBEEP  
C1  
C2  
TEXAS  
INSTRUMENTS  
9
R2  
SHUTDOWN  
L IN+  
L LINE–  
LOUT–  
GND  
GND  
L HP  
+
C13  
GND  
SLOP275  
LOUT+  
VDD  
TPA00242 EVM Board  
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 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).  
2-5  
Quick Start  
 
Quick Start List for Stand-Alone  
Evaluation module preparations  
6) 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 OFF. To keep the module amplifier IC in the  
single-ended output mode regardless of the control input state, set jumper  
S3 to ON.  
7) 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.  
Control inputs  
8) 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. 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 TPA0242 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 TPA0242 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 TPA0242 EVM Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . 3–16  
3.5 TPA0242 Audio Power Amplifier Evaluation Module Parts List . . 3–18  
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  
power input connector J1, J2, and/or V  
power  
CC  
DD  
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  
ICC  
JP4  
C1+  
F1  
VR1  
DC  
Power  
In/Out  
Power  
Input  
R2  
R1  
Audio  
Power  
Amps  
Signal Conditioning  
Audio  
Input  
Speaker  
Output  
Mode  
Mute  
Polarity  
Lo  
****CAUTION****  
Do not insert or remove  
EVM boards with power  
applied  
Hi  
Stereo  
Headphone  
Output  
Plug-N-Play Audio Amplifier  
Evaluation Platform  
SLOP097 Rev. C.1  
R3  
R4  
HP Out  
R5  
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  
continuouspowerperchannelinto3-loads. TheamplifierICcanbeoperated  
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 31) or wired directly into circuits or equipment. The module  
has single in-line header connector pins mounted to the under side of the  
board. These pins allow the module to be plugged into the TI platform, which  
automatically makes all the signal input and output, power, and control  
connections to the module.  
The module connection pins are on 0.1-inch centers to allow easy use with  
standard perf board and plug board-based prototyping systems. Or, the EVM  
can be wired directly into existing circuits and equipment when used stand-  
alone.  
The module appears in Figure 3–2 and its schematic is shown in Figure 33.  
Figure 3–2. TPA0242 EVM  
VDD  
GND  
C10  
R HP  
GND  
ROUT+  
GND  
+
ROUT–  
R LINE–  
SHUTDOWN  
HP/LINE  
SE/BTL  
R IN+  
S1  
R1  
C11  
PCBEEP  
C1  
C2  
U1  
TEXAS  
INSTRUMENTS  
R2  
SHUTDOWN  
L IN+  
L LINE–  
LOUT–  
GND  
GND  
L HP  
+
C13  
SLOP275  
LOUT+  
VDD  
GND  
TPA00242 EVM Board  
3-3  
Details  
 
The TPA0242 Audio Power Amplifier Evaluation Module  
Figure 3–3. TPA0242 EVM Schematic Diagram  
R LINE –  
R2  
50 k  
C1  
0.47 µF  
1
2
3
4
24  
23  
22  
21  
20  
19  
18  
17  
16  
15  
14  
13  
R1  
100 kΩ  
V
GND  
GND  
DD  
TPA0242  
CW  
V
DD  
S3  
PCB ENABLE RLINEIN  
VOLUME SHUTDOWN  
SHUTDOWN  
TP1  
HP/LINE  
S1  
CCW  
S4  
SHUTDOWN  
LOUT+  
LLINEIN  
LHPIN  
ROUT+  
RHPIN  
R OUT +  
R HP  
C3  
SE/BTL  
L OUT +  
L LINE –  
5
0.47 µF  
C7  
0.47 µF  
6
7
V
DD  
L HP  
C4  
R3  
C8  
0.47 µF 0 Ω  
0.47 µF  
V
DD  
PV  
DD  
PV  
DD  
C12  
10 µF  
V
DD  
C6  
47 nF  
8
C10  
10 µF  
RIN  
CLK  
ROUT–  
SE/BTL  
PC–BEEP  
GND  
C5  
0.1 µF  
GND  
9
GND  
LOUT–  
LIN  
C2  
0.47 µF  
10  
11  
12  
ROUT–  
SE/BTL  
R IN +  
PCBEEP  
L OUT –  
L IN +  
BYPASS  
GND  
R4  
100 kΩ  
C12  
0.47 µF  
S2  
C11  
0.47 µF  
C9  
0.47 µF  
V
DD  
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 pin. In the BTL mode, the line inputs are automatically  
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.  
3-4  
Details  
 
The TPA0242 Audio Power Amplifier Evaluation Module  
Figure 3–4. TPA0242 Amplifier IC  
L HP  
MUX  
L IN  
L LINE  
VOLUME  
CONTROL  
PC BEEP  
PC BEEP  
VOLUME  
R LINE  
R IN  
MUX  
R HP  
SE/BTL  
HP/LINE  
3.2.2 Inputs and Gain  
Each channel has two separate signal inputs, line and headphone (HP), that  
are automatically selected with the output mode (SE/BTL). An input multi-  
plexor 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.  
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.  
3-5  
Details  
 
The TPA0242 Audio Power Amplifier Evaluation Module  
PotentiometerR2adjuststhegainoftheinternalpreampstageoftheTPA0242  
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. Table 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)  
VOLUME (Pin 3)  
VOLUME (Pin 3)  
BTL  
GAIN  
(dB)  
BTL  
GAIN  
(dB)  
BTL  
GAIN  
(dB)  
FROM  
(V)  
TO  
(V)  
FROM  
(V)  
TO  
(V)  
FROM  
(V)  
TO  
(V)  
0
0.15  
0.28  
0.39  
0.5  
20  
18  
16  
14  
12  
10  
8
1.28  
1.39  
1.5  
1.39  
1.5  
–2  
–4  
2.52  
2.63  
2.74  
2.86  
2.97  
3.08  
3.2  
2.63  
2.74  
2.86  
2.97  
3.08  
3.2  
–24  
–26  
–28  
–30  
–32  
–34  
–36  
–38  
–40  
–85  
0.15  
0.28  
0.39  
0.5  
1.62  
1.73  
1.84  
1.95  
2.07  
2.18  
2.29  
2.41  
2.52  
–6  
1.62  
1.73  
1.84  
1.95  
2.07  
2.18  
2.29  
2.41  
–8  
0.61  
0.73  
0.84  
0.95  
1.06  
1.17  
1.28  
–10  
–12  
–14  
–16  
–18  
–20  
–22  
0.61  
0.73  
0.84  
0.95  
1.06  
1.17  
3.31  
3.42  
3.54  
5
6
3.31  
3.42  
3.54  
4
2
0
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 TPA0242 line inputs allow the use of a single-ended or differential 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  
differentialsource, connectthepositiveleadoftheaudiosourcetotheRLINE–  
(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  
 
The TPA0242 Audio Power Amplifier Evaluation Module  
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 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.  
3.2.6 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.  
In the single-ended mode, the amplifiers inside the TPA0242 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.  
3-7  
Details  
 
Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform  
3.3 Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform  
The TPA0242 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  
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.  
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 the platform.  
3-8  
Details  
 
Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform  
3.3.2 TPA0242 Module Jumper Settings and Switches  
The TPA0242 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 ON  
means that a shunt is installed across the two pins of the jumper. Setting a  
jumper to OFF 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  
R LINE –  
R2  
50 kΩ  
C1  
0.47 µF  
1
2
24  
23  
22  
21  
20  
19  
18  
17  
16  
15  
14  
13  
R1  
100 kΩ  
V
GND  
GND  
DD  
TPA0242  
CW  
V
DD  
S3  
PCB ENABLE RLINEIN  
VOLUME SHUTDOWN  
SHUTDOWN  
TP1  
HP/LINE  
S1  
3
CCW  
S4  
SHUTDOWN  
4
LOUT+  
LLINEIN  
LHPIN  
ROUT+  
RHPIN  
R OUT +  
R HP  
C3  
SE/BTL  
L OUT +  
L LINE –  
5
0.47 µF  
C7  
0.47 µF  
6
V
DD  
L HP  
C4  
R3  
C8  
0.47 µF 0 Ω  
7
0.47 µF  
V
DD  
PV  
DD  
PV  
DD  
C12  
10 µF  
V
DD  
C6  
47 nF  
8
C10  
10 µF  
RIN  
CLK  
ROUT–  
SE/BTL  
PC–BEEP  
GND  
C5  
0.1 µF  
GND  
9
GND  
LOUT–  
LIN  
C2  
0.47 µF  
10  
11  
12  
ROUT–  
SE/BTL  
R IN +  
PCBEEP  
L OUT –  
L IN +  
BYPASS  
GND  
R4  
C12  
100 kΩ  
0.47 µF  
S2  
C11  
0.47 µF  
C9  
0.47 µF  
V
DD  
3-9  
Details  
 
Using The TPA0242 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.  
JumperS3connectstheSE/BTL output mode control input pin on the amplifier  
IC directly to V , so that when S3 is ON, the IC is held in the single-ended  
DD  
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  
To 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 V , so that when S3 is ON, the IC is held in the HP input mode re-  
DD  
gardless of the state of the HP/LINE module control input. When S3 is OFF,  
apulldownresistoronthemoduleholdstheICinputcontrolmodeinputpinlow,  
allowing the IC to use the LINE inputs as the source of an input signal.  
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 input mode control pin on the amplifier  
IC and the SE/BTL output mode control pin on the amplifier IC are shorted to-  
gether 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.  
3-10  
Details  
 
Using The TPA0242 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 36.  
Figure 3–6. Platform Signal Routing and Outputs  
Off  
+
R
R
L
R
U2  
TPA0242  
Amplifier EVM  
J7, J8, J9  
Speaker  
Outputs  
U1  
Signal  
Conditioning  
Audio  
Input  
S2  
+
L
L
On  
U2U4  
R
+
R
U5  
Stereo  
Headphone  
Amplifier  
J10  
Headphone  
Output  
GND  
S3  
L
+
L
U5  
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.  
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 TPA0242 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).  
To keep the TPA0242 amplifier outputs separated, set switchS3 to the  
headphone amplifier position (U5) and use the speaker outputs (J7,  
J8, and J9)  
To route the TPA0242 amplifier outputs to the headphone output jack  
(J10), set switch S3 to the power amplifier position (U2 – U4) — use  
this setting only if the TPA0242 EVM is to drive single-ended loads  
connected to J10  
3-11  
Details  
 
Using The TPA0242 EVM With the Plug-N-Play Evaluation Platform  
3.3.4 Mute (Shutdown)/Mode  
The TPA0242 EVM is equipped with a shutdown control input pin. When this  
input is pulled to ground, the TPA0242 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)  
outputmode. WhenthemodecontrolinputistiedtoGND, themoduleoperates  
in the BTL output mode. When this input is tied to V , the module operates  
DD  
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.  
3.3.4.1 Headphone Jack Control Signals  
The platform headphone output jack (J10) contains an internal switch that  
changesthestateofapairofcontrollineswhenaplugisinserted(Figure3–7).  
Each control line is pulled down by a 1-kresistor to ground (R4 and R5). The  
switch in the headphone jack pulls one line or the other up to V  
through a  
DD  
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 Ω  
Polarity  
JP8  
JP6  
Mode  
Mute  
Lo  
U2  
Power  
Amplifier  
J10  
Headphone  
Jack  
Hi  
R4  
1 kΩ  
R5  
1 kΩ  
SPK  
(U2–U4)  
3-12  
Details  
 
Using The TPA0242 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.  
To shut down the TPA0242 amplifier module using the control signal  
from the platform headphone jack, jumper JP6 to MUTE  
To switch the output mode of the TPA0242 amplifier between BTL and  
single-ended using the control signal from the platform headphone  
jack, jumper JP6 to MODE  
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 TPA0242:  
To shut down the TPA0242 amplifier module when a plug is inserted  
into the headphone jack, jumper JP8 to Lo (this is the typical setting).  
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 TPA0242:  
To switch the TPA0242 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).  
ToswitchtheTPA0242amplifiermoduletotheBTLoutputmodewhen  
a plug is inserted into the headphone jack, jumper JP8 to Lo.  
3-13  
Details  
 
Power Requirements  
3.3.5 Power Requirements  
The TPA0242 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  
supply from a wide variety of  
DD  
unregulated V  
voltage inputs between approximately 5.5 V and 12 V,  
CC  
including an onboard 9-V battery. Or, an external regulated power source can  
be used to supply V voltage to the platform and the TPA0242 evaluation  
DD  
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.  
The platform is equipped with overvoltage and reverse-polarity supply voltage  
input protection in the form of fused crowbar circuits.  
V
voltage applied to platform screw terminals J6 MUST NOT exceed  
DD  
the absolute maximum rating for the TPA0242 amplifier IC installed on the  
evaluation module (6 V) or damage to the IC may result. In no case should  
V
voltage of the incorrect polarity or in excess of 6.1 V be applied to  
DD  
screw terminals J6 of the platform, or the power protection circuit on the  
V
line will trip.  
DD  
V
voltage applied to the platform MUST NOT exceed the maximum  
CC  
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  
voltage applied to the platform exceed  
CC  
15 V, or the overvoltage protection circuit on the V  
bus will trip.  
CC  
3-14  
Details  
 
Inputs and Outputs  
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  
inputconnectorsmountedonthemodulecircuitboard. TheTPA0242EVMhas  
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.  
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 TPA0242 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 36). 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 38), requiring single-ended operation  
of the power amplifiers.  
Figure 3–8. Typical Headphone Plug  
Left  
Right  
GND  
3-15  
Details  
 
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 pin must be  
able to supply enough current to overcome the pullup resistor on the module  
(100 k).  
3.4.1 TPA0242 EVM Connected for BTL Output  
Figure 3–9. TPA0242 EVM Connected for Stereo BTL Output  
VDD  
GND  
C10  
R HP  
GND  
ROUT+  
GND  
+
Right  
Audio  
Input  
(Right)  
ROUT–  
R LINE–  
SHUTDOWN  
HP/LINE  
SE/BTL  
R IN+  
S1  
R1  
C11  
PCBEEP  
C1  
C2  
U1  
TEXAS  
INSTRUMENTS  
External Shut  
Down Control  
(active low)  
R2  
SHUTDOWN  
L IN+  
Audio  
Input  
(Left)  
L LINE–  
LOUT–  
GND  
GND  
L HP  
Left  
+
C13  
SLOP275  
LOUT+  
VDD  
GND  
TPA00242 EVM Board  
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)  
VDD  
GND  
C10  
R HP  
GND  
ROUT+  
GND  
+
ROUT–  
R LINE–  
+
33 µF –  
1000 µF  
SHUTDOWN  
HP/LINE  
SE/BTL  
R IN+  
S1  
R1  
C11  
PCBEEP  
C1  
C2  
U1  
TEXAS  
INSTRUMENTS  
33 µF –  
1000 µF  
R2  
SHUTDOWN  
L IN+  
+
L LINE–  
LOUT–  
GND  
GND  
L HP  
Audio  
Input  
(Left)  
+
C13  
SLOP275  
LOUT+  
VDD  
GND  
TPA00242 EVM Board  
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  
3-17  
Details  
 
TPA0242 Audio Power Amplifier Evaluation Module Parts List  
3.5 TPA0242 Audio Power Amplifier Evaluation Module Parts List  
Table 3–4.TPA0242 EVM Parts List  
EVM  
Qty.  
Manufacturer/  
Part Number  
Reference  
C5  
Description  
Size  
Digi-Key Number  
Capacitor, 0.1 µF, 10%,  
nonpolarized  
0805  
1
Murata  
GRM40-X7R104K25  
C1, C2, C3,  
C4, C7, C8,  
C9, C11, C12  
Capacitor, 0.47 µF,  
80%/–20%, nonpolarized  
0805  
9
Murata  
GRM40-Y5V474Z16  
C6  
Capacitor, 0.47 nF,  
80%/–20%, nonpolarized  
0805  
A
1
2
2
1
1
1
2
1
1
1
1
C10, C13  
R1, R4  
R3  
Capacitor, 10 µF, 6.3 V  
Panasonic  
Digi-Key  
ECS-TOJY106R  
PCS1106CT-ND  
Resistor, 100 k, 1/8 W,  
5%  
0805  
0805  
Panasonic  
Digi-Key  
ERJ-6GEYJ104V  
P100KABK-ND  
Resistor, 0 , 1/8 W  
Panasonic  
Digi-Key  
ERJ-6GEYJ200V  
P02ABK-ND  
R2  
Potentiometer, 50 k, ST  
SL, thru hole  
Bourns  
Digi-Key  
3362P–1–503  
3362P–503–ND  
S1  
Switch, momentary  
Test points, red  
Header, 2 position  
Shunts  
SMD  
Panasonic  
Digi-Key  
P8050SCT-ND  
P8050SCT-ND  
TP1, TP2  
S3  
Farnell  
240–345  
2 mm  
2 mm  
Norcomp  
2JM–G  
Digi-Key  
2163S-02-ND  
P3  
Digi-Key  
SPE1302–ND  
U1  
IC, TPA0242, audio  
amplifier, 1 W, 2 channel  
24 pin  
TSSOP  
TI  
TPA0242PWP  
PCB1  
PCB, TPA0242 EVM  
TI  
SLOP275  
3-18  
Details  
 

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