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Copyright 1998, 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
TP A122 150-mW STEREO AUDIO POWER AMPLIFIER
(literature number SLOS211) This is the data sheet for the TPA122
audio amplifier integrated circuit.
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.
Preface
(literature
Trademarks
TI is a trademark of Texas Instruments Incorporated.
This chapter provides an overview of the Texas Instruments (TI) TPA122
MSOP Audio Amplifier Evaluation Module (SLOP125). It includes a list of EVM
features, a brief description of the module illustrated with a pictorial diagram,
and a list of EVM specifications.
The TI TPA122 MSOP Audio Amplifier Evaluation Module and the TI
Plug-N-Play Audio Amplifier Evaluation Platform include the following
features:
-
TPA122 MSOP Stereo Audio Power Amplifier Evaluation Module
J
Dual channel, single-ended operation
J
150-mW output power into 8 Ω at 5 V
J
2.5-V to 5.5-V operation
J
Very low distortion — THD+N is less than 0.006% @ 1 kHz and less
than 0.07% from 20 Hz to 20 kHz into 10-kΩ loads; less than 0.02% @
1 kHz and less than 0.4% from 20 Hz to 20 kHz into 32-Ω loads; and
less than 0.05% @ 1 kHz and less than 0.8% from 20 Hz to 20 kHz into
8-Ω loads
J
Extremely low current consumption in shutdown mode
J
Internal thermal and short-circuit protection
J
Internal pop reduction circuitry
-
Quick and Easy Configuration with the TI Plug-N-Play Audio Amplifier
Evaluation Platform
J
Evaluation module is designed to simply plug into the platform,
automatically making all signal, control, and power connections
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
Onboard 9-V battery
J
External 5-V – 15-V (VCC) supply inputs
J
External regulated VDD supply input
J
Socket for on-board 5-V VDD voltage regulator EVM
J
On-board overvoltage and reverse polarity power protection
-
Platform Audio Input and Output Connections
J
Left and right RCA phono jack inputs
1-2
J
Miniature stereo phone jack input
J
Left and right RCA phono jack outputs
J
Left and right compression speaker terminal outputs
J
Miniature stereo headphone jack output
Introduction
1.2Description
The TP A122 MSOP Audio Power Amplifier Evaluation Module is a complete,
low-power stereo audio power amplifier for high-fidelity line-level output,
headphone, and small speaker applications. It consists of the TI TPA122
150-mW Stereo Audio Power Amplifier IC in a very small MSOP package,
along with a small number of other parts mounted on a circuit board that is
approximately one and a quarter inches square (Figure 1–1).
Figure 1–1.The TI TPA122 Audio Amplifier Evaluation Module
Description
Shutdown
IN1
GND
TEXAS
INSTRUMENTS
IN2
GND
†
Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE
VDDGND
+
S1
R1
C1
C2
C3
SLOP127
TPA122 MSOP EVM
C5
R2
R3
U1
R5
R4
Vo1
GND
†
C4
GND
Vo2
Single in-line header pins are mounted to the underside of the module circuit
board to allow the EVM to be plugged into the TI Plug-N-Play Audio Amplifier
Evaluation Platform, or to be wired directly into existing circuits and equipment
when used stand-alone.
The platform has room for a single TPA122 evaluation module. It is a
convenient vehicle for demonstrating TI’s audio power amplifier and related
evaluation modules. The EVMs simply plug into the platform, which
automatically provides power to the modules, interconnects them correctly,
and connects them to a versatile array of standard audio input and output jacks
and connectors. Easy-to-use configuration controls allow the platform and
EVMs to quickly model many possible end-equipment configurations.
There is nothing to build, nothing to solder, and nothing but the speakers
included with the platform to “hook up.”
1.3TPA122 MSOP EVM Specifications
Supply voltage range, V
Supply current, I
DD
Continuous output power, P
Audio input voltage, V
Minimum load impedance, R
The steps in this chapter can be followed to quickly prepare the TP A122 MSOP
audio amplifier EVM for use. Using the TPA122 MSOP EVM with the TI
Plug-N-Play Audio Amplifier Evaluation Platform is a quick and easy way to
connect power, signal and control inputs, and signal outputs to the EVM using
standard connectors. However, the audio amplifier evaluation module can be
used stand-alone by making connections directly to the module pins, and can
be wired directly into existing circuits or equipment.
The platform switch and jumper settings shown in T able 2–1 are typical for the
TP A122 MSOP EVM and will cause the TPA122 IC to shut down/mute when
a plug is removed from platform headphone jack J10.
Table 2–1. Typical TI Plug-N-Play Platform Jumper and Switch Settings for the
TPA122 MSOP EVM
EVMJP6JP7JP8S2S3
TPA122XHiXNote 2U5
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 Input Polarity and Maximum Voltage
Always ensure that the polarity and voltage of the external power
connected to V
input connector J6 are correct. Overvoltage or reverse-polarity
power input connector J1, J2, and/or VDD power
CC
power applied to these terminals can open onboard soldered-in
fuses and cause other damage to the platform, installed evaluation
modules, and/or the power source.
Inserting or Removing EVM Boards
Do not insert or remove EVM boards with power applied — damage
to the EVM board, the platform, or both may result.
Power
Input
6b
Audio
Input
8
Figure 2–1.
SOURCE
VCC
J1
In
+
D4
AC/DC
In
J2
Right
In
Stereo
In
Left
In
1997
Quick Start Platform Map
6b
JP3
JP2
JP1
DC
VCC(J1)
AC/DC
(J2)
Batt
D1
D2
D3
J3
Signal Conditioning
J4
J5
****CAUTION****
Do not insert or remove
EVM boards with power
Follow these steps when using the TPA122 MSOP EVM with the TI
Plug-N-Play Audio Amplifier Evaluation Platform (see the platform user’s
guide, SLOU01 1, for additional details). Numbered callouts for selected steps
are shown in Figure 2–1 and details appear in Chapter 3.
-
Platform preparations
Quick Start List for Platform
1) Ensure that all external power sources are set to
power switch S1 is set to
OFF.
OFF
and that the platform
2) Install a TP A122 MSOP module in platform socket U5, taking care to align
the module pins correctly.
3) Use switch S2 to select or bypass the signal conditioning EVM (U1).
4) Set control signal Polarity jumper JP7 to
Hi.
5) Set Hp source switch S3 to U5 to route the output signal to the headphone
Jack (J10).
Table 2–2. Platform Jumper and Switch Settings for the TPA122 MSOP EVM
EVMJP6JP7JP8S2S3
TPA122XHiXNote 2U5
Notes:1) X = Don’t care
2) Set S2 to
to
-
Power supply
6) Select and connect the power supply:
a) Connect an external regulated power supply set to a voltage between
2.5 V and 5.5 V to platform V
to observe marked polarity, or
ON
OFF
when signal conditioning board is installed in U1; set S2
when no signal conditioning board is installed.
power input connector J6, taking care
DD
b) Install a 3-V to 5-V voltage regulator EVM (SLVP097 or equiv.) in
platform socket U6. Install a 9-V battery in B1 or connect a 7 V – 12
V power source to a platform V
power input J1 or J2 and jumper the
CC
appropriate power input (see platform user’s guide).
-
Inputs and outputs
7) Ensure that signal source level is set to minimum.
8) Connect the audio source to left and right RCA phono jacks J3 and J5 or
stereo miniature phone jack J4.
9) Connect 32-Ω headphones to headphone jack J10.
-
Power up
10) Verify correct voltage and input polarity and set the external power supply
to
ON.
If VCC and an onboard regulator EVM are used to provide VDD, set
platform power switch S1 to
ON.
Platform LED2 should light indicating the presence of VDD, and the evaluation
modules installed on the platform should begin operation.
11) Adjust the signal source level as needed.
Quick Start
2-3
Quick Start List for Stand-Alone
2.3Quick Start List for Stand-Alone
Follow these steps to use the TPA122 MSOP EVM stand-alone or when
connecting it into existing circuits or equipment. Connections to the TPA122
MSOP module header pins can be made via individual sockets,
wire-wrapping, or soldering to the pins, either on the top or the bottom of the
module circuit board (Figure 2–2). Details appear in Chapter 3.
Figure 2–2.
†
Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE
Quick Start Module Map
IN1
GND
TEXAS
INSTRUMENTS
IN2
GND
-
Power supply
1) Ensure that all external power sources are set to
Shutdown
S1
R1
C1
C2
C3
SLOP127
TPA122 MSOP EVM
VDDGND
+
C5
R2
R3
†
U1
R5
R4
Vo1
GND
C4
GND
Vo2
OFF.
2) Connect an external regulated power supply set to 5 V to the module VDD
and GND pins, taking care to observe marked polarity.
-
Inputs and outputs
3) Ensure that the signal source level is set to minimum.
2-4
-
Power-up
4) Connect the audio source to the module IN1, IN2, and GND pins, taking
care to observe marked polarity.
5) Connect the Shutdown pin to V
6) Connect 32-Ω headphones to the module V
through a Normally Open switch.
DD
1, VO2 pins through 33 µF
O
to 1000 µF output-coupling capacitors (figure 3–8) and return to the GND
pin, or
7) For line output, connections to the V
1 and VO2 pins must be made
O
through 33 µF to 1000 µF output-coupling capacitors and returned to
GND.
8) Verify correct voltage and input polarity and set the external power supply
to
ON.
The EVM should begin operation.
9) Adjust the signal source level as needed.
Quick Start
Chapter 3
Details
This chapter provides details on the TPA122 IC, the evaluation module, the
steps in the Quick-Start List, additional application information, and a parts list
for the TPA122 MSOP evaluation module.
3.5TPA122 MSOP Audio Power Amplifier EVM Parts List3–12. . . . . . . . . .
Details
3-1
Precautions
3.1Precautions
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
****CAUTION****
Do not insert or remove
EVM boards with power
applied
GND
TP1
U5
U2-U4
U5
HP
Source
HP(U5)
S3
R3
R4
JP6
Polarity
Lo
Hi
JP7
+
+
Mode
Mute
Spk(U2-U4)
Out
JP8
C3 C2
HP Out
J9
Left
Stereo
J10
R5
Headphone
Output
Details
The TPA122 MSOP Audio Power Amplifier Evaluation Module
3.2The TPA122 MSOP Audio Power Amplifier Evaluation Module
The TP A122 MSOP Audio Power Amplifier Evaluation Module is powered by
a TP A122 150-mW Stereo Audio Amplifier IC. It includes a shutdown control
signal input with onboard switch and can drive either line-level outputs, 32-Ω
headphones, or 8-Ω speakers.
The evaluation module can be used with the TI Plug-N-Play Audio Amplifier
Evaluation Platform (Figure 3–1) or wired directly into circuits or equipment.
The module has single in-line header connector pins mounted to the under
side of the board. These pins allow the module to be plugged into the TI
platform, which automatically makes all the signal input and output, power, and
control connections to the module.
The module connection pins are on 0.1-inch centers to allow easy use with
standard perf board and plug board-based prototyping systems. Or, the EVM
can be wired directly into existing circuits and equipment when used
stand-alone.
The module appears in Figure 3–2 and its schematic is shown in Figure 3–3.
Figure 3–2.TPA122 MSOP EVM
Shutdown
IN1
GND
TEXAS
INSTRUMENTS
IN2
GND
†
Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE
VDDGND
+
S1
R1
C1
C2
C3
SLOP127
TPA122 MSOP EVM
R4
R2
U1
C5
R3
†
R5
Vo1
GND
C4
GND
Vo2
Figure 3–3.TPA122 MSOP EVM Schematic Diagram
Shutdown
(VDD to
Shutdown)
Audio Input 1
Audio Input 2
S1
V
C1
1 µF
C3
1 µF
DD
NO
R1
20 kΩ
R2
20 kΩ
R4
20 kΩ
R3
80 kΩ
C2
1 µF
1
2
3
4
Vo1
IN 1
Bypass
GND
TPA122
MSOP
Shutdown
V
Vo2
IN 2
DD
8
10 µF
7
6
5
C5
+
R5
80 kΩ
C4
1 µF
Vo1
V
DD
2.5 to 5.5 V
GND
Vo2
Details
3-3
The TPA122 MSOP Audio Power Amplifier Evaluation Module
3.2.1TPA122 Audio Amplifier IC
The TPA122 audio amplifier IC is a CMOS device intended primarily for
high-performance line-level output, headphone driver, and small speaker
applications. It is supplied in a very small surface-mount MSOP package and
has been designed to operate from low supply voltages (between
approximately 2.5 V and 5.5 V) and to deliver up to approximately 150 mW into
8-Ω speakers with low distortion. As a line-level driver, distortion levels
(THD+N) are below 0.07% into 10-kΩ loads across the audio band (20 Hz to
20 kHz). As a headphone driver, distortion levels are below 0.4% into 32-Ω
loads across the audio band. And as a speaker driver, distortion levels are
below 0.8% into 8-Ω loads across the audio band. Typical applications include
portable computers, desktop computers, personal audio, toys, games, and
similar audio applications.
The IC includes two separate internal amplifiers, depop circuitry, and a
common shutdown control (Figure 3–4). The load for each channel is
connected between the V
pin and GND through a coupling capacitor. For
O
more information, see the TPA122 amplifier IC data sheet, TI Literature
Number SLOS21 1.
Figure 3–4.TPA122 Amplifier IC
Stereo Audio
Input
R
From System
Control
L
8
R
F
R
I
C
I
C
B
R
I
C
I
R
F
IN1
2
Bypass
3
Shutdown
5
IN2
6
–
+
Bias
Control
–
+
VO1
VO2
C
1
4
7
C
C
C
V
DD
C
S
RLR
L
Stereo
3-4
Details
3.2.2Module Gain
The TPA122 MSOP Audio Power Amplifier Evaluation Module
The TP A122 MSOP evaluation module has a set gain of 4 (inverting) for each
channel. However, the gain can be adjusted to a maximum of approximately
10 (inverting) by changing the value of feedback resistors (R2 and R4, Figure
3–3). Use the following equation to determine the value of R
R
Gain+–
F
R
I
F:
The TP A122 amplifier IC, like most other amplifiers, exhibits its best distortion
and noise performance at lower gain levels. In addition, higher gain levels
require a small compensation capacitor to ensure stability (see the TPA122
data sheet).
Gain versus total harmonic distortion (THD) and gain versus signal-to-noise
ratio (SNR) should be considered in each application. Both the module input
signal level and the TP A122 MSOP module gain should be adjusted to obtain
the lowest overall distortion level for a particular overall gain. A quick rule of
thumb (everything else being equal): the module input signal level should be
as high as possible without clipping or overloading the TP A122 input, and the
TPA122 gain should be kept as low as possible.
3.2.3Shutdown
When the shutdown terminal of the TP A122 amplifier IC is taken high, the IC
ceases operation and enters a very low power state (65 µA at V
10 µA at V
= 3.3 V Typ). This is accomplished by applying a control signal
DD
= 5 V and
DD
to the module SD pin or by pressing the Shutdown switch, S1, on the module.
When the control signal goes low or is removed (or the switch is released),
amplifier operation resumes.
The Plug-N-Play platform can generate the mute signal for the module either
when a plug is
plug is
removed
inserted
into the platform headphone output jack or when the
, as selected by a platform jumper (JP7).
Details
3-5
Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
3.3Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
The TPA122 MSOP Audio Amplifier Evaluation Module is designed for use
with the TI Plug-N-Play Audio Amplifier Evaluation Platform. It simply plugs
into socket U5.
The following paragraphs provide additional details for using the TP A122 EVM
with the platform.
3.3.1Installing 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.
3.3.1.1EVM Insertion
3.3.1.2EVM Removal
1) Remove all power from the evaluation platform.
2) Locate socket U5 on the platform.
3) Orient the module correctly.
4) Carefully align the pins of the module with the socket pin receptacles.
5) Gently press the module into place.
6) Check to be sure that all pins are seated properly and that none are bent
over.
1) Remove all power from the evaluation platform.
2) Using an appropriate tool as a lever, gently pry up one side of the module
a short distance.
3) Change to the opposite side of the module and use the tool to pry that side
up a short distance.
4) Alternate between sides, prying the module up a little more each time to
avoid bending the pins, until it comes loose from the socket.
3-6
5) Lift the EVM off the platform.
Details
Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
3.3.2Signal Routing
Signal flow on the platform is controlled by two signal routing switches, as
shown in Figure 3–5.
Figure 3–5.Platform Signal Routing and Outputs
U2 Stereo Power
Amplifier EVM
R
Audio
Input
L
U1
Signal
Conditioning
Off
S2
On
U3
Mono Power
Amplifier EVM
U4
Mono Power
Amplifier EVM
U5
TPA122 MSOP
Headphone
Amplifier EVM
+
GND
R
–
J7, J8, J9
Speaker
Outputs
–
L
+
R
+
–
J10
Headphone
Output
–
+
L
R
L
U2–U4
R
S3
L
U5
3.3.2.1Signal Conditioning
The audio signal from the input jacks can be applied to the signal conditioning
socket (U1) if an EVM is installed there, or socket U1 can be bypassed and the
audio input signal applied directly to the inputs of the TP A122 power amplifiers.
-
Switch S2 selects or bypasses signal conditioning.
3.3.2.2Headphone Output Jack
Switch S3 is the source select for the stereo headphone output jack, J10. The
headphone jack is capacitively coupled (via 470 µF electrolytics). It can output
either the signal from the the TPA122 MSOP headphone amplifier in socket
U5 or the signal from power amplifiers installed in socket U2 or in sockets U3
and U4, as determined by the setting of headphone source select switch S3.
When S3 is set to the headphone amplifier position (U5), the headphone jack
is connected to the headphone amplifier EVM output lines. When a plug is
inserted into the jack, signals output through J10 are returned to platform
ground. A switch inside the headphone jack produces a control signal that can
be routed to the headphone amplifier socket to shutdown the TP A122 MSOP
EVM when the headphone plug is removed.
-
Switch S3 connects the headphone jack to either the headphone amplifier
platform socket (U5) or to the platform power amplifier sockets (U2 – U4).
Details
3-7
Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
3.3.3Shutdown
The TP A122 MSOP EVM is equipped with a shutdown control input pin. When
this input is tied to V
operation and enters an ultra-low-power state. When the EVM shutdown
control input is tied to GND or allowed to float, amplifier operation resumes.
In typical applications, as often found in notebook computers, portable audio
products, and such, the internal speakers mute when headphones are
plugged into the headphone jack, or internal speakers mute when external
speakers are connected. In applications using separate speaker and
headphone amplifiers, the one not being used can be muted to conserve
power.
3.3.3.1Headphone Jack Control Signals
The platform headphone output jack (J10) contains an internal switch that
changes the state of a pair of control lines when a plug is inserted or removed
(Figure 3–6). Each control line is pulled down by a 1-kΩ resistor to ground (R4
and R5). The switch in the headphone jack pulls one line or the other up to V
through a 240 Ω resistor (R3), depending on whether or not a plug is inserted
in J10.
, the TPA122 amplifier IC on the module ceases
DD
DD
Figure 3–6.Shutdown Polarity Control
V
DD
R3
240 Ω
J10
Headphone
Jack
3.3.3.2Shutdown Polarity Select (JP7)
A 3-pin jumper header (JP7) on the platform selects the shutdown control
signal polarity by connecting either the active-high or the active-low line from
the headphone jack to platform socket U5. The TPA122 MSOP EVM shuts
down when V
J
To shut down the TPA122 MSOP amplifier module
inserted into the headphone jack, jumper JP7 to
J
To shut down the TPA122 MSOP amplifier module
inserted into the headphone jack, jumper JP7 to
setting).
is applied to the module SD pin.
DD
R4
1 kΩ
R5
1 kΩ
Polarity
Lo
Hi
(U5)
JP7
HP
Shutdown
Lo
U5
Headphone
Amplifier
when
a plug is
Hi
.
until
a plug is
(this is the typical
3-8
Details
3.3.4Power Requirements
The TPA122 MSOP Audio Power Amplifier Evaluation Module can operate
from a V
The TI Plug-N-Play Audio Amplifier Evaluation Platform with a voltage
regulator EVM installed on it can provide a regulated 3.3-V or 5-V V
from a wide variety of unregulated V
5.5 V and 12 V, including an onboard 9 -V battery. Or, an external regulated
power source can be used to supply V
TPA122 evaluation module installed on it.
The platform is equipped with overvoltage and reverse-polarity supply voltage
input protection in the form of fused crowbar circuits.
-
VDD voltage applied to platform screw terminals J6
the absolute maximum rating for the TP A122 amplifier IC installed on the
evaluation module (5.5 V), or damage to the IC may result. In no case
should V
to screw terminals J6 of the platform, or the power protection circuit on the
V
DD
-
VCC voltage applied to the platform
voltage input specified for the voltage regulator module installed in socket
U6 (12 V for the SLVP097), or damage to the voltage regulator module
may result. In no case should V
15 V, or the overvoltage protection circuit on the V
Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
voltage between approximately 2.5 V and 5.5 V.
DD
supply
DD
voltage inputs between approximately
CC
voltage to the platform and the
DD
MUST NOT
voltage of the incorrect polarity or in excess of 6.1 V be applied
DD
exceed
line will trip.
MUST NOT
voltage applied to the platform exceed
CC
exceed the maximum
bus will trip.
CC
Details
3-9
Using The TPA122 MSOP EVM With the Plug-N-Play Evaluation Platform
3.3.5Inputs and Outputs
The TI Plug-N-Play Audio Amplifier Evaluation Platform is equipped with
several standard conectors for audio inputs and outputs.
3.3.5.1Inputs
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.
3.3.5.2Outputs
Output signals from the headphone amplifier (U5) leave the platform through
a miniature (1/8″) stereo headphone jack (J10). Amplified audio output signals
from the power amplifiers (U2 – U4) leave the platform through left and right
RCA phono jacks (J7 and J9), left and right pairs of compression connectors
for stripped speaker wires (J8), and optionally, through the headphone jack.
The audio output lines from the power amplifiers are separate all the way to
the edge of the platform (output jacks J7, J8, and J9) — the OUT– lines from
the power amplifier sockets are not tied to each other or to platform ground.
This allows the power amplifier EVMs to operate in the highly-efficient
bridge-tied load configuration.
The headphone jack (J10) is capacitively coupled to source select switch S3,
which connects J10 to the output lines of either the headphone amplifier
socket or the power amplifier sockets (Figure 3–5). When the TPA122 MSOP
EVM output signal is routed to J10 by S3, signals output via J10 are returned
to platform ground when a plug is inserted (Figure 3–7).
Figure 3–7.Typical Headphone Plug
LeftRightGND
3-10
Details
Using The TPA122 MSOP EVM Stand-Alone
3.4Using The TPA122 MSOP EVM Stand-Alone
Using the TPA122 MSOP Audio Power Amplifier Evaluation Module
stand-alone is much the same as using it with the platform. The same 2.5-V
to 5.5-V power supply requirement exists.
Note that the shutdown signal applied to the EVM SD pin must be able to
supply enough current to overcome the pulldown resistor on the module
(20 kΩ).
3.4.1TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier
Figure 3–8.TPA122 MSOP EVM Connected as a Stereo Headphone Amplifier
5 VDC
Shutdown
Audio
Input
(Right)
Audio
Input
(Left)
†
Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE
NO
Shutdown
IN1
GND
TEXAS
INSTRUMENTS
IN2
GND
VDDGND
+
S1
R1
C1
C2
C3
SLOP127
TPA122 MSOP EVM
R4
R2
U1
C5
R3
†
R5
GND
C4
GND
Vo2
Vo1
+
+
33 µF –
1000 µF
33 µF –
1000 µF
Details
3-11
TP A122 MSOP Audio Power Amplifier Evaluation Module Parts List
3.5TPA122 MSOP Audio Power Amplifier Evaluation Module Parts List
Table 3–1. TPA122 MSOP EVM Parts List
Ref.DescriptionSize
C1, C2,
C3, C4
C5Capacitor, 10 µF, 6.3 V,
R1, R2,R4Resistor, 20 kΩ, 1/16 W,
R3, R5Resistor, 80 kΩ, 1/16 W,
S1Switch, momentarySMD1Panasonic
U1IC, TPA122, audio
PCB1PCB, TPA122 MSOP EVM1SLOP127
†
Due to the very small size of the MSOP IC package, the standard part number TPA122 is replaced with the code TIAAE
Capacitor, 1 µF,
80%/–20%, nonpolarized,
SMD
SMD
5%, SMD
5%, SMD
amplifier, 150 mW,
2-channel, SMD
Terminal post headers11SullinsDigi-Key
06034Murata
A1Panasonic
06033Panasonic
06032Panasonic
MSOP-81TI
EVM
Qty.
Manufacturer/
Part Number
GRM39-Y5V105Z10PT
ECS-TOJY106R
ERJ-3GSYJ203
ERJ-3GSYJ803
P8048SCT-ND
TP A122DGN
†
Vendor/Number
Newark
Digi-Key
PCS1106CT-ND
Digi-Key
Digi-Key
Digi-Key
P8048SCT-ND
S1022-36-ND
3-12
Details
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