Texas Instruments Stereo Amplifier TPA301 User Manual

User’s Guide  
2001  
Mixed-Signal Products  
SLOU014A  
 
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.  
TPA301 350-mW Low-Voltage Audio Power Amplifier (literature  
number SLOS208) This is the data sheet for the TPA301 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  
TPA301 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4  
Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1  
3.1  
3.2  
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2  
The TPA301 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3  
3.2.1 TPA301 Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4  
3.2.2 BTL Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4  
3.2.3 Single-Ended Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4  
3.2.4 Module Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5  
3.2.5 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5  
Using The TPA301 EVM With The Plug-N-Play Evaluation Platform . . . . . . . . . . . . . . . 3-6  
3.3.1 Installing and Removing EVM Boards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6  
3.3.2 Signal Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7  
3.3.3 Muting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8  
3.3.4 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9  
3.3.5 Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10  
Using The TPA301 EVM Stand-ALone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11  
3.4.1 TPA301 EVM Connected for BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11  
3.4.2 TPA301 EVM Connected for Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . 3-12  
TPA301 Audio Amplifier Evaluation Module Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13  
3.3  
3.4  
3.5  
v
 
Figures  
11  
21  
22  
31  
32  
33  
34  
35  
36  
37  
38  
39  
The TI TPA301 Audio Amplifier Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3  
Quick Start Platform Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2  
Quick Start Module Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4  
The TI Plug-N-Play Audio Amplifier Evaluation Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2  
TPA301 EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3  
TPA301 EVM Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3  
TPA301 Audio Amplifier IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4  
Platform Signal Routing and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7  
Mute/Mode and Polarity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8  
Typical Headphone Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10  
TPA301 EVM Connected for Stereo BTL Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11  
TPA301 EVM Connected for Stereo Single-Ended Output . . . . . . . . . . . . . . . . . . . . . . . . . 3-12  
Tables  
21  
22  
31  
Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA301 . . . . . . . . . . 2-1  
Platform Jumper and Switch Settings for the TPA301 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3  
TPA301 EVM Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13  
vi  
 
Chapter 1  
Introduction  
This chapter provides an overview of the Texas Instruments (TI ) TPA301  
audio amplifier evaluation module (SLOP115). 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 TPA301 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–3  
1-1  
 
Feature Highlights  
1.1 Feature Highlights  
The TI TPA301 audio amplifier evaluation module and the TI plug-n-play audio  
amplifier evaluation platform include the following features:  
TPA301 Low-Voltage Audio Power Amplifier Evaluation Module  
Single channel, bridge-tied load (BTL) or single-ended operation  
3.3-V and 5-V operation  
350 mW output power into 8 at 5 V, BTL  
Ultra-low current consumption in shutdown/mute mode  
Internal thermal and short-circuit protection  
Module gain adjustable between approximately 2 and 22  
Quick and Easy Configuration With the TI Plug-N-Play Audio Amplifier  
Evaluation Platform  
Evaluation module is designed to simply plug into the platform, auto-  
matically making all signal, control, and power connections  
Platform provides flexible power options  
Jumpers on the platform select power and module control options  
Switches on the platform route signals  
Platform provides quick and easy audio input and output connections  
Platform Power Options  
Onboard 9-V battery  
External 5-V 15-V 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 TPA301 audio power amplifier evaluation module is a complete, low-pow-  
er single-channel audio power amplifier. It consists of the TI TPA301 350-mW  
low-voltage audio power amplifier IC along with a small number of other parts  
mounted on a circuit board that is approximately one and a quarter inches  
square (Figure 11).  
Figure 11. The TI TPA301 Audio Amplifier Evaluation Module  
+5 V GND  
Shutdown  
R5  
C6  
C3  
C5  
S1  
DL  
R1  
C2  
OUT–  
GND  
U1  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
3  
IN+  
R4  
GND  
TPA301  
EVM  
Single in-line header pins are mounted to the underside of the module circuit  
board to allow the EVM to be plugged into the TI plug-n-play audio amplifier  
evaluation platform, or to be wired directly into existing circuits and equipment  
when used stand-alone.  
The platform has room for a pair of TPA301 evaluation modules and is a  
convenient vehicle for demonstrating TIs 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 TPA301 EVM Specifications  
Supply voltage range, V  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 V to 5.5 V  
DD  
Supply current, I  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 mA, max  
DD  
Continuous output power, P : 8-BTL, V =5 V: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 mW  
O
DD  
32-BTL, V =5 V: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 mW  
DD  
Audio input voltage, V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Vpp, max  
I
Minimum load impedance, R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Ω  
L
1-3  
Introduction  
 
1-4  
Introduction  
 
Chapter 2  
Quick Start  
The steps in this chapter can be followed to quickly prepare the TPA301 audio  
amplifier EVM for use. While using the TPA301 with the TI plug-n-play audio  
amplifier evaluation platform is a quick and easy way to connect power, signal  
and control inputs, and signal outputs to the EVM using standard connectors,  
the audio amplifier evaluation module can be used stand-alone by making  
connections directly to the module pins, and can be wired directly into existing  
circuits or equipment.  
The platform switch and jumper settings shown in Table 21 are typical for the  
TPA301 EVM and will cause the TPA301 to mute when a plug is inserted into  
platform headphone jack J10.  
Table 21.Typical TI Plug-N-Play Platform Jumper and Switch Settings for the TPA301  
EVM  
JP6  
JP7  
JP8  
S2  
S3  
TPA301  
Mute  
X
Hi  
Note 2  
X
Notes: 1) X = Dont care  
2) Set S2 to ON when signal conditioning board is installed in U1; set S2  
to OFF when no signal conditioning board is installed.  
Topic  
Page  
2.1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
2.2 Quick Start List for Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
2.3 Quick Start List for Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24  
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 21. Quick Start Platform Map  
6b  
6b  
1
10  
6b  
ICC  
JP4  
C1+  
F1  
VR1  
DC  
Power  
In/Out  
6a  
Power  
Input  
6b  
R2  
R1  
Audio  
Power  
Amps  
Signal Conditioning  
Audio  
Input  
8
Speaker  
Output  
9
5
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  
HP Out  
R3  
R4  
R5  
3
2
4
2-2  
Quick Start  
 
Quick Start List for Platform  
2.2 Quick Start List for Platform  
Use the following steps when using the TPA301 EVM with the TI plug-n-play  
audio amplifier evaluation platform (see the platform users guide, SLOU011,  
for additional details). Numbered callouts for selected steps are shown in  
Figure 21 and details appear in Chapter 3.  
Platform preparations  
1) EnsurethatallexternalpowersourcesaresettoOFF andthattheplatform  
power switch S1 is set to OFF  
2) Install a TPA301 module in platform sockets U3 and U4 for stereo  
operation (or a module in either U3 or U4 for single channel operation),  
taking care to align the module pins correctly  
3) Use switch S2 to select or bypass the signal conditioning EVM (U1)  
4) Set control signal Polarity jumper JP8 to Hi  
5) Set jumper JP6 to select the Mute control input (causes the TPA301 to  
mute if a plug is inserted into platform headphone jack J10)  
Table 22.Platform Jumper and Switch Settings for the TPA301  
EVM  
TPA301  
Notes: 1) X = Dont care  
JP6  
JP7  
JP8  
Hi  
S2  
S3  
Mute  
X
Note 2  
X
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  
6) Select and connect the power supply:  
a) Connect an external regulated power supply set to a voltage between  
2.5 V and 5.5 V to platform V  
to observe marked polarity,  
power input connector J6 taking care  
or  
DD  
b) Install a voltage regulator EVM (SLVP097 or equiv.) in platform socket  
U6. Install a 9-V battery in B1 or connect a 7 V 12 V power source  
to a platform V  
power input (see platform users guide)  
power input J1 or J2 and jumper the appropriate  
CC  
Inputs and outputs  
7) Ensure that signal source level adjustments and EVM gain, R4, are set to  
minimum  
8) Connect the audio source to left and right RCA phono jacks J3 and J5 or  
stereo miniature phone jack J4  
9) Connect 8-32-speakers to left and right RCA jacks J7 and J9 or to  
stripped wire connectors J8  
Power-up  
10) Verify correct voltage and input polarity and set the external power supply  
to ON. If V and an onboard regulator EVM are used to provide V , set  
CC  
DD  
platform power switch S1 to ON  
Platform LED2 should light indicating the presence of V , and the evaluation  
DD  
modules installed on the platform should begin operation.  
11) Adjust the signal source level and EVM gain level (R4) as needed  
2-3  
Quick Start  
 
Quick Start List for Stand-Alone  
2.3 Quick Start List for Stand-Alone  
Use the following steps to use the TPA301 EVM stand-alone or when  
connecting it into existing circuits or equipment. Connections to the TPA301  
module header pins can be made via individual sockets, wire-wrapping, or  
solderingtothepins, eitheronthetoporthebottomofthemodulecircuitboard.  
Numbered callouts for selected steps are shown in Figure 22 and details  
appear in Chapter 3.  
Figure 22. Quick Start Module Map  
2
+5 V GND  
R5  
Shutdown  
5
C6  
C3  
C5  
S1  
DL  
R1  
C2  
OUT–  
GND  
6
7
U1  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
3  
IN+  
R4  
4
GND  
TPA301  
EVM  
Gain Adjust  
Power supply  
1) Ensure that all external power sources are set to OFF  
2) Connect an external regulated power supply set to 5 V to the module +5V  
and GND pins taking care to observe marked polarity  
Inputs and outputs  
3) Ensure that signal source level adjustments and EVM gain (R4) are set to  
minimum  
4) Connect the audio source to the module IN+ and GND pins taking care to  
observe marked polarity  
5) Connect the Shutdown pin to V  
through a normally open switch  
DD  
6) For BTL output, connect an 8-32-speaker to the module OUT+ and  
OUTpins, or  
7) For single-ended output, connect a headphone or an 8-32-speaker  
to the module OUT+ and GND pins through a 33 µF to 1000 µF output-  
coupling capacitor (figure 39)  
Power-up  
8) Verify correct voltage and input polarity and set the external power supply  
to ON  
The EVM should begin operation.  
9) Adjust the signal source level and EVM gain level (R4) as needed  
2-4  
Quick Start  
 
Chapter 3  
Details  
This chapter provides details on the TPA301 IC, the evaluation module, and  
the steps in the Quick-Start List, additional application information, and a parts  
list for the TPA301 evaluation module.  
Topic  
Page  
3.1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
3.2 The TPA301 Audio Power Amplifier Evaluation Module . . . . . . . . . . . 33  
3.3 Using The TPA301 EVM With The Plug-N-Play  
Evaluation Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36  
3.4 Using The TPA301 EVM Stand-Alone . . . . . . . . . . . . . . . . . . . . . . . . . . 311  
3.5 TPA301 Audio Power Amplifier Evaluation Module Parts List . . . 313  
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 31. 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  
HP Out  
R3  
R4  
R5  
3-2  
Details  
 
The TPA301 Audio Power Amplifier Evaluation Module  
3.2 The TPA301 Audio Power Amplifier Evaluation Module  
TheTPA301audiopoweramplifierevaluationmoduleispoweredbyaTPA301  
350-mW low-power audio amplifier IC and includes onboard gain adjustment,  
a shutdown control signal input with onboard switch, and can be operated in  
either the BTL or single-ended output mode.  
The module can be used with the TI plug-n-play audio amplifier evaluation  
platform (Figure 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 to be wired  
directly into existing circuits and equipment when used stand-alone.  
The module appears in Figure 32 and its schematic is shown in Figure 33.  
Figure 32. TPA301 EVM  
+5 V GND  
R5  
Shutdown  
C6  
C3  
C5  
S1  
DL  
R1  
C2  
OUT–  
GND  
U1  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
3  
IN+  
R4  
GND  
TPA301  
EVM  
Figure 33. TPA301 EVM Schematic Diagram  
VDD  
2.5 V to 5.5 V  
GND  
C6  
10 µF  
+
C5  
0.1 µF  
S1  
No  
1
R5  
510 Ω  
8
7
6
Dummy  
Load  
Shutdown V  
Shutdown  
O–  
2
3
4
R1  
20 kΩ  
Bypass GND  
C2  
2.2 µF  
OUT–  
In+  
V
DD  
C3  
2.2 µF  
GND  
5
C1  
1 µF  
In–  
V
O+  
OUT+  
Audio Input+  
Audio Input–  
R2  
20 kΩ  
C4  
5 pF  
R3  
20 kΩ  
R4  
200 kΩ  
3-3  
Details  
 
The TPA301 Audio Power Amplifier Evaluation Module  
3.2.1 TPA301 Audio Amplifier IC  
TheTPA301audioamplifierICisaCMOSdeviceintendedprimarilyforbridge-  
tied load (BTL) operation in battery-powered applications. It is supplied in a  
verysmallsurface-mountpackageandhasbeendesignedtooperatefromlow  
supply voltages (between approximately 2.5 V and 5.5 V) and deliver up to  
approximately 350 mW into an 8-, BTL (Figure 34). Typical applications in-  
clude portable phones, toys, games, and similar hand-held audio applications.  
Figure 34. TPA301 Amplifier IC  
4
_
+
5
IN –  
3
OUT+  
IN+  
6
V
2
DD  
V
DD  
/2  
_
+
8
7
OUT–  
GND  
The amplifier IC includes two separate amplifiers that operate 180°  
out-of-phase with each other for increased power (BTL). The speaker load is  
connected directly across OUT+ and OUT, and neither line is connected to  
ground. Although the amplifier can operate in the single-ended mode, there  
are many benefits to the BTL output configuration including no bulky output  
coupling capacitors and quadruple the output power. For more information,  
see the TPA301 amplifier IC data sheet, TI Literature Number SLOS208.  
3.2.2 BTL Operation  
To operate in the bridge-tied load output configuration, 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 OUTline be  
isolatednotonlyfromsystemground, butalsofromtheOUTlinesofanyother  
amplifiers in the system. The platform provides such isolated output lines from  
the EVM sockets directly to separate left and right speaker connectors.  
3.2.3 SIngle-Ended Operation  
For single-ended operation, the speaker (or headphone) load is connected to  
the module OUT+ output pin through a coupling capacitor, and to  
platform/system ground. The module OUTpin can be connected to the  
module DL pin, a dummy-load circuit on the module, for improved amplifier  
stability (however, this is not required). A 470-µF electrolytic coupling  
capacitorisprovidedontheplatforminthesignalpathtotheheadphoneoutput  
jack.  
3-4  
Details  
 
The TPA301 Audio Power Amplifier Evaluation Module  
In the single-ended mode, the amplifier inside the TPA301 IC that drives the  
OUTline still operates and dissipates power even though it is not being used  
to help drive the load. A better choice for low-power applications that operate  
in the single-ended mode from time to time might be the TPA311 (SLOP116),  
which shuts down the unused internal amplifier for reduced power consump-  
tion when operating in the single-ended mode.  
3.2.4 Module Gain  
The TPA301 evaluation module can be set for an overall gain of between 2 and  
22 by adjustment of the the onboard gain control, R4. The TPA301 amplifier  
IC, as most other amplifiers, exhibits its best distortion and noise performance  
at lower gain levels (see the TPA301 data sheet). Even so, the TPA301 at its  
highest gain setting has significantly less distortion than most low-cost  
speakers.  
Gain versus total harmonic distortion (THD) should be considered in each  
application. Both the module input signal level and the TPA301 module gain  
should be adjusted to obtain the lowest overall distortion level for a particular  
overall gain. A quick rule of thumb (everything else being equal): the module  
input signal level should be as high as possible without clipping or overloading  
the TPA301 input, and the TPA301 gain kept as low as possible.  
3.2.5 Shutdown  
When the shutdown terminal of the TPA301 amplifier IC is taken high, the IC  
ceases operation and enters an ultralow-power state. This is accomplished by  
applying a control signal to the module shutdown pin or by pressing the shut-  
down switch, S1, on the module. When the control signal goes low or is re-  
moved (or the switch is released), amplifier operation resumes.  
The P-N-P platform can generate the shutdown (mute) signal for the module  
either when a plug is inserted into the platform headphone output jack or when  
the plug is removed, as selected by a platform jumper (JP8).  
3-5  
Details  
 
Using The TPA301 EVM With the Plug-N-Play Evaluation Platform  
3.3 Using The TPA301 EVM With the Plug-N-Play Evaluation Platform  
The TPA301 audio amplifier evaluation module was designed to be used with  
the TI plug-n-play audio amplifier evaluation platform. It simply plugs into  
socket U3 or U4.  
The following paragraphs provide additional details for using the TPA301EVM  
with the platform.  
3.3.1 Installing and Removing EVM Boards  
TI plug-n-play evaluation modules use single-in-line header pins installed on  
the underside of the module circuit board to plug into sockets on the platform.  
The EVM pins and the platform sockets are keyed such that only the correct  
type of EVM can be installed in a particular socket, and then only with the  
proper orientation.  
Evaluation modules are easily removed from the platform by simply prying  
them up and lifting them out of their sockets. Care must be taken, however, to  
prevent bending the pins.  
3.3.1.1 EVM Insertion  
1) Remove all power from the evaluation platform  
2) Locate socket U3 or U4 on the platform  
3) Orient the module correctly  
4) Carefully align the pins of the module with the socket pin receptacles  
5) Gently press the module into place  
6) Check to be sure that all pins are seated properly and that none are bent  
over  
3.3.1.2 EVM Removal  
1) Remove all power from the evaluation platform  
2) Using an appropriate tool as a lever, gently pry up one side of the module  
a small amount  
3) Change to the opposite side of the module and use the tool to pry that side  
up a small amount  
4) Alternate between sides, prying the module up a little more each time to  
avoid bending the pins, until it comes loose from the socket  
5) Lift the EVM off of the platform  
3-6  
Details  
 
Using The TPA301 EVM With the Plug-N-Play Evaluation Platform  
3.3.2 Signal Routing  
Signal flow on the platform is controlled by two signal routing switches, as  
shown in Figure 35.  
Figure 35. Platform Signal Routing and Outputs  
Off  
U3  
TPA301  
Amplifier EVM  
+
R
R
L
R
J7, J8, J9  
Speaker  
Outputs  
U1  
Signal  
Conditioning  
Audio  
Input  
S2  
U4  
TPA301  
L
+
Amplifier EVM  
L
On  
U2U4  
R
+
R
U5  
Stereo  
Headphone  
Amplifier  
J10  
Headphone  
Output  
GND  
S3  
L
+
L
U5  
3.3.2.1 Signal Conditioning  
The audio signal from the input jacks can be applied to the signal conditioning  
socket (U1) if an EVM is installed there, or socket U1 can be bypassed and the  
audioinputsignalapplieddirectlytotheinputsoftheTPA301poweramplifiers.  
Switch S2 selects signal conditioning or bypasses it  
3.3.2.2 Headphone Output Jack  
Switch S3 is the source select for the stereo headphone output jack, J10. The  
headphone jack is capacitively coupled (via 470 µF electrolytics) and can  
output either the signal from the headphone amplifier in socket U5, or the  
signal from the TPA301 power amplifiers installed in sockets U3 and U4, as  
determined by the setting of headphone source select switch S3.  
When S3 is set to the power amplifier position (U2 U4), the headphone jack  
is connected to the TP301 power amplifier OUT+ output lines. When a plug is  
inserted into the jack, signals output through J10 are returned to platform  
ground, requiring single-ended power amplifier operation. A switch inside the  
headphone jack produces a control signal that can be routed to the power  
amplifier sockets to shut down the TPA301 EVMs when a plug is inserted.  
Source select switch S3 connects the headphone jack to the output lines of  
either the headphone amplifier socket U5, or the power amplifier sockets  
(U2 U4).  
To keep the TPA301 amplifier outputs separated, set switch S3 to the  
headphone amplifier position (U5) and use the speaker outputs (J7,  
J8, and J9)  
To route the TPA301 amplifier outputs to the headphone output jack  
(J10), set switch S3 to the power amplifier position (U2 – U4) and  
reverse the jumper on JP8 to prevent muting of the TPA301 module  
when a plug is inserted into J10 use this setting only if the TPA301  
EVMs are to drive single-ended loads connected to J10  
3-7  
Details  
 
Using The TPA301 EVM With the Plug-N-Play Evaluation Platform  
3.3.3 Muting  
The TPA301 EVM is equipped with a mute (shutdown) control input pin. When  
thisinputistiedtoV , theTPA301amplifierIConthemoduleshutsdownand  
DD  
assumes an ultra-low power mode. When the control input is tied to GND or  
allowed to float, amplifier operation resumes.  
The typical application, as often found in notebook computers, portable audio  
products, and such, would have the internal speakers mute when headphones  
are plugged into the headphone jack, or have internal speakers mute when  
external speakers are connected. In applications using separate speaker and  
headphone amplifiers, the one not being used can be shut down (muted) to  
conserve power.  
3.3.3.1 Headphone Jack Control Signals  
The platform headphone output jack (J10) contains an internal switch that  
changes the state of a pair of control lines when a plug is inserted. 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 240 resistor  
DD  
(R3) depending on whether a plug is inserted in J10 or not (Figure 36).  
Figure 36. Mute/Mode and Polarity Control  
V
DD  
R3  
240 Ω  
Polarity  
JP8  
JP6  
Mode  
Mute  
Lo  
U3, U4  
Power  
Amplifiers  
J10  
Headphone  
Jack  
Hi  
R4  
1 kΩ  
R5  
1 kΩ  
SPK  
(U2U4)  
3.3.3.2 Mute Polarity Select (JP8)  
A three-pin jumper header (JP8), functioning as a SPDT switch, selects the  
controlsignalpolaritybyconnectingeithertheactive-lowortheactive-highline  
from the headphone jack to jumper JP6.  
To mute the TPA301 amplifier module when a plug is inserted into the  
headphone jack, jumper JP8 to Hi.  
To mute the TPA301 amplifier module until a plug is inserted into the  
headphone jack, jumper JP8 to Lo.  
3.3.3.3 Mute Select (JP6)  
A second three-pin jumper header (JP6) routes the control signal from the  
headphone jack to either the mute or the mode pin of the evaluation module.  
To mute the TPA301 amplifier module when a plug is inserted into the  
headphone jack, jumper JP6 to MUTE.  
To not affect the TPA301 amplifier when a plug is inserted into the  
headphone jack, jumper JP6 to MODE or leave JP6 unjumpered.  
3-8  
Details  
 
Power Requirements  
3.3.4 Power Requirements  
The TPA301 audio evaluation module can operate from any voltage between  
approximately 2.5 V and 5.5 V, however, the TPA301 amplifier IC on the  
module is characterized for operation at 3.3 V and 5 V. For best performance  
(highest output power with lowest distortion), the module should be operated  
at approximately 5 V unless there is a specific reason for operating it from a  
lower voltage.  
The TI plug-n-play audio amplifier evaluation platform with a voltage regulator  
EVM installed on it can provide a regulated V  
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 TPA301 evaluation  
DD  
modules installed on it.  
The platform is equipped with overvoltage and reverse-polarity supply voltage  
input protection in the form of fused crowbar circuits.  
V
voltage applied to platform screw terminals J6 MUST NOT exceed  
DD  
the absolute maximum rating for the TPA301 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  
3-9  
Details  
 
Inputs and Outputs  
3.3.5 Inputs and Outputs  
The TI plug-n-play audio amplifier evaluation platform is equipped with several  
standard conectors for audio inputs and outputs.  
3.3.5.1 Inputs  
In most cases, audio signals enter the platform through either a pair of RCA  
phono jacks (J3 and J5) or a miniature (1/8) stereo phone jack (J4). Certain  
signal conditioning and amplifier EVMs, however, may have additional signal  
input connectors mounted on the module circuit board.  
The platform audio signal input jacks (J3, J4, and J5) are of the closed-circuit  
type, grounding the signal input lines when no plugs are inserted.  
3.3.5.2 Outputs  
Amplified audio output signals leave the platform through left and right RCA  
phono jacks (J7 and J9), left and right pairs of compression connectors for  
stripped speaker wires (J8), and optionally, through a miniature (1/8) stereo  
phone jack (J10), for headphones.  
The audio output lines from the power amplifiers are separate all the way to  
the edge of the platform (output jacks J7, J8, and J9) the OUTlines from  
the power amplifier sockets are not tied to each other or to platform ground.  
This allows the TPA301 power amplifier EVMs to operate in the highly-efficient  
bridge-tied load configuration.  
The headphone jack (J10) is capacitively coupled to source select switch S3,  
which connects J10 to the output lines of either the headphone amplifier  
socket or the power amplifier sockets (Figure 35). When the TPA301 output  
signal is routed to J10 by S3, signals output via J10 are returned to platform  
ground when a plug is inserted (Figure 37), requiring single-ended operation  
of the power amplifiers.  
Figure 37. Typical Headphone Plug  
Left  
Right  
GND  
3-10  
Details  
 
Using The TPA301 EVM Stand-Alone  
3.4 Using The TPA301 EVM Stand-Alone  
Using the TPA301 audio power amplifier evaluation module stand-alone is  
much the same as using it with the platform. The same 2.5-V to 5.5-V power  
supply range and the isolated OUT+ and OUTlines for BTL operation re-  
quirement exists.  
Note that the mute signal applied to the EVM shutdown pins must be able to  
supply enough current to overcome the pulldown resistors on the modules  
(20 k|| 20 kfor two EVMs).  
3.4.1 TPA301 EVM Connected for BTL Output  
Figure 38. TPA301 EVM Connected for Stereo BTL Output  
5 VDC  
+5 V GND  
Shutdown  
R5  
C6  
C3  
C5  
S1  
DL  
R1  
C2  
OUT–  
Right  
GND  
U1  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
Audio  
Input  
(Right)  
3  
IN+  
R4  
GND  
TPA301  
EVM  
GND  
5 VDC  
+5 V GND  
Shutdown  
External Mute  
Control  
(active high)  
R5  
C6  
C3  
U1  
C5  
S1  
DL  
R1  
C2  
OUT–  
GND  
Left  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
Audio  
Input  
(Left)  
3  
IN+  
R4  
GND  
TPA301  
EVM  
3-11  
Details  
 
Using The TPA301 EVM Stand-Alone  
3.4.2 TPA301 EVM Connected for Single-Ended Output  
Figure 39. TPA301 EVM Connected for Stereo Single-Ended Output  
5 VDC  
+5 V GND  
Shutdown  
R5  
C6  
C3  
C5  
S1  
DL  
R1  
C2  
OUT–  
GND  
U1  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
Audio  
Input  
(Right)  
3  
IN+  
+
R4  
33 µF –  
1000 µF  
GND  
TPA301  
EVM  
GND  
5 VDC  
+5 V GND  
Shutdown  
External Mute  
Control  
(active high)  
R5  
C6  
C3  
U1  
C5  
S1  
33 µF –  
DL  
R1  
C2  
1000 µF  
+
OUT–  
GND  
R2  
C1  
C4  
R3  
OUT+  
Lit.#  
SLOP 115  
Audio  
Input  
(Left)  
3  
IN+  
R4  
GND  
TPA301  
EVM  
3-12  
Details  
 
TPA301 Audio Power Amplifier Evaluation Module Parts List  
3.5 TPA301 Audio Power Amplifier Evaluation Module Parts List  
Table 31.TPA301 EVM Parts List  
EVM  
Qty.  
Manufacturer/  
Part Number  
Ref.  
R4  
Description  
Size  
Vendor Number  
Trim Pot, 200 kCermet ST  
SL, (through hole)  
1
1
1
2
1
1
3
1
1
1
1
Bourns  
3323P-1-204  
Digi-Key  
3323P-204-ND  
C6  
Capacitor, 10 µF, 6.3 V  
A
Panasonic  
ECS-TOJY106R  
Digi-Key  
PCS1106CT-ND  
C1  
Capacitor, 1 µF,  
+80%/20%, nonpolarized  
1206  
1206  
1206  
0805  
1206  
1206  
Murata  
GRM42-6Y5V105Z16BL  
Newark  
93F2254  
C2, C3  
C5  
Capacitor, 2.2 µF, 20%,  
nonpolarized  
TDK  
C3216X5R1A225  
Capacitor, 0.1 µF, 16 V  
Panasonic  
ECS-H1CY105R  
Digi-Key  
PCT104BCT-ND  
C4  
Capacitor, 5 pF  
Panasonic  
ECU-V1H050CCN  
Digi-Key  
PCC050CNCT-ND  
R1, R2, Resistor, 20 k, 1/8 W, 5%  
R3  
Panasonic  
ERJ-8GEYJ203  
Digi-Key  
P20KECT-ND  
R5  
Resistor, 510 , 1/8W  
Panasonic  
ERJ-8GEYJ511  
Digi-Key  
P510ECT-ND  
S1  
Switch, momentary  
Panasonic  
P8048SCT-ND  
Digi-Key  
P8048SCT-ND  
U1  
IC, TPA301, audio amplifier, SOIC-8  
350 mW, mono  
TI  
TPA301  
PCB1  
PCB, TPA301 sample EVM  
Note: All items are SMD except as noted.  
3-13  
Details  
 
3-14  
Details  
 

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