Texas Instruments TPA3255EVM User manual

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TPA3255EVM
User's Guide
SLOU441–July 2016
TPA3255EVM
This User’s Guide describes the operation of the evaluation module (TPA3255EVM, rev A) for the
TPA3255 315-W Stereo/600-W mono PurePath™ Ultra-HD Analog Input Power Stage. The user’s guide
also provides design information, which includes schematics, BOM, and PCB layout. For questions and
support go to the E2E forums (e2e.ti.com).
The main contents of this document are:
• Hardware descriptions and implementation
• Design information
Related documents:
• TPA3255 Data Sheet (SLASEA8)
Topic ........................................................................................................................... Page
2 Hardware Overview .............................................................................................. 3
3 TPA3255EVM Setup.............................................................................................. 6
4 Using TPA3255EVM in Different Output Configurations............................................ 9
5 Board Layouts, Bill of Materials, and Schematic .................................................... 12

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TPA3255EVM
1 Trademarks
PurePath is a trademark of Texas Instruments.

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TPA3255EVM
2 Hardware Overview
The TPA3255EVM PurePath™ Ultra-HD evaluation module demonstrates the TPA3255DDV integrated
circuit from Texas Instruments. The TPA3255DDV is a high-performance high-power class-D amplifier that
enables true premium sound quality with high-efficiency class-D technology. It features an advance
integrated feedback design and high-speed gate driver error correction (PurePath Ultra-HD), which
enables ultra-low distortion across the audio band and superior audio quality. This EVM supports two BTL
(stereo 2.0) output channels, one PBTL (mono 0.1) output channel, one BTL plus two SE (2.1) output
channels, and four SE (4.0) output channels configurations. The NE5532 is a High Performance Audio Op
Amp designed to allow TPA3255DDV operation with differential or single ended input signals to the EVM
with differential inputs yielding the optimal performance. TPA3255EVM is a complete 2-Vrms analog input
2 × 315-W stereo/1 × 600-W mono high-power amplifier ready for evaluation and excellent listening
experience.
Figure 1. TPA3255EVM
2.1 TPA3255EVM Features
The TPA3255EVM has the following features:
• Stereo PurePath Ultra-HD evaluation module
• Self-contained protection system (short circuit, clip, and thermal)
• Standard 4-VRMS differential input or single-ended line input
• BTL, PBTL, and SE output configuration support
• Frequency adjust and oscillator sync interface
• Single supply voltage range 14–53.5 V
• Double-sided, plated-through, 2-oz. Cu 2-layer PCB layout

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2.2 TPA3255EVM Frequency Adjust
The TPA3255EVM offers hardware trimmed oscillator frequency by external control of the FREQ_ADJ pin.
The Frequency adjust can be used to reduce interference problems while using a radio receiver tuned
within the AM band, the switching frequency can be changed from nominal to lower values. These values
should be chosen such that the nominal and the lower value switching frequencies together results in the
fewest cases of interference throughout the AM band. The oscillator frequency can be selected by the
value of the FREQ_ADJ resistor connected to GND in master mode according to Table 1.
Table 1. Frequency Adjust Master Mode Selection
Master Mode Resistor to GND
Nominal 30 kΩ
AM1 20 kΩ
AM2 10 kΩ
For slave-mode operation, turn off the oscillator by pulling the FREQ_ADJ pin to DVDD. This configures
the OSC_I/O pins as inputs to be slaved from an external differential clock. In a master/slave system inter-
channel delay is automatically set up between the switching phases of the audio channels, which can be
illustrated by no idle channels switching at the same time. This will not influence the audio output, but only
the switch timing to minimize noise coupling between audio channels through the power supply. This will
optimize audio performance and result in better operating conditions for the power supply. The inter-
channel delay will be set up for a slave device depending on the polarity of the OSC_I/O connection such
that slave mode 1 is selected by connecting the OSC_I/O of the master device with the OSC_I/O of the
slave device with the same polarity (+ to + and – to –), while slave mode 2 is selected by connecting the
OSC_I/O's with the inverse polarity (+ to – and – to +).
2.3 TPA3255EVM Single-Ended and Differential Input
The TPA3255EVM supports both differential and single-ended inputs. For single-ended inputs, J4 and/or
J19 jumpers are set to the SE position, so that the TPA3255EVM uses the NE5532 to convert the single-
ended input signal to differential to properly drive the differential inputs of the TPA3255. The input RCA
jack, J3, is used to provide INA inputs and RCA jack J14 is used to provide INB inputs. RCA jack J18 is
used to provide INC inputs and RCA jack J15 is used to provide IND inputs with differential inputs.
For differential input operation, J4 and/or J19 jumpers are set to the DIFF position, and the TPA3255EVM
uses the NE5532 to buffer the differential input signal to the differential inputs of the TPA3255. The input
RCA jack, J3, is used to provide INA, RCA jack J14 provides INB, RCA jack J18 provides INC, and RCA
jack J15 provides IND with differential inputs.
NOTE: Single-ended input settings on the TPA3255EVM should only be used for channels with
output configuration BTL or PBTL, not SE. For SE output configuration J4 and/or J19
jumpers for that channel must be set to the DIFF position, so the input signal INx is mapped
directly to OUTx.

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TPA3255EVM
2.4 TPA3255EVM Clip Overtemperature and Fault Indicators
The TPA3255EVM is equipped with LED indicators that illuminate when the FAULT and/or CLIP_OTW pin
goes low. See Table 2 and (SLASEA8) for more details.
Table 2. Fault and Clip Overtemperature Status
FAULT CLIP_OTW Description
0 0 Overtemperature (OTE) or overload (OLP) or undervoltage (UVP). Junction temperature higher
than 125°C (overtemperature warning).
0 0 Overload (OLP) or undervoltage (UVP). Junction temperature higher than 125°C (overtemperature
warning).
0 1 Overload (OLP) or undervoltage (UVP). Junction temperature lower than 125°C.
1 0 Junction temperature higher than 125°C (overtemperature warning)
1 1 Junction temperature lower than 125°C and no OLP or UVP faults (normal operation)

Power Supply
SE A/B Input
DIFF A Input
DIFF B Input
TPA3255
under
Heat Sink
SE C/D Input
DIFF C Input
DIFF D Input
3.3-V and 12-V
LEDs
Warning LEDs
RESET Switch
OUTD
OUTC
GND
GND
OUTB
OUTA
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3 TPA3255EVM Setup
This section describes the TPA3255EVM hardware setup and connection.
3.1 TPA3255EVM Setup
Figure 2 illustrates the TPA3255EVM connection.
Figure 2. TPA3255EVM Connections
3.2 Hardware Requirements
The following hardware is required for this EVM:
• TPA3255EVM (AAP053-001)
• Power supply 5–14 A/18–53.5 VDC
• Two 2–8 Ω(≈300 W) speakers/resistor loads
• Four speaker/banana cables
• RCA input cables
• Analog output audio source

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3.3 Hardware Default Setup BTL (2.0)
BTL (2.0) default hardware setup is as follows:
• Remove the EVM from the ESD bag.
• Check that jumpers are in their default state as shown in Figure 1 and Table 3 for stereo BTL
operation:
Table 3. Stereo BTL Default Jumper States
Jumper Setting Comment
J29 IN PVDD to 15-V BUCK
J31 IN 12-V LDO to 12-V TERM
J32 IN 3.3-V LDO to 3.3-V TERM
J33 IN 3.3-V LDO to 3.3-V TERM
J21 IN CSTART SE
J16 3 to 4 MASTER MODE
J5 2 to 3 M1 – BTL
J6 2 to 3 M2 – BTL
J22 IN OUTA CAP SHUNT
J23 IN OUTB CAP SHUNT
J24 IN OUTC CAP SHUNT
J25 IN OUTD CAP SHUNT
J26 2 to 3 INC SELECT
J27 2 to 3 IND SELECT
J7 OUT PBTL SELECT INC
J8 OUT PBTL SELECT IND
J10 OUT INC/D DIFF INPUT
J12 OUT INC/D DIFF INPUT
J4 1 to 2 INA/B SE INPUT
J19 1 to 2 INC/D SE INPUT
• Set S1 to the RESET position.
• Set power supply to 51 V (14–53.5-V range) and current to 10 A (5–14-A range). Do not power up until
all connections are completed.
• Connect power supply to TPA3255 EVM positive terminal to PVDD (RED) and negative terminal to
GND (BLACK).
• Connect left channel speaker/power resistor load (4–8 Ω) to TPA3255 EVM positive output terminal to
OUTA (RED) and AP analog input channel A positive terminal.
• Connect left channel speaker/power resistor load (4–8 Ω) to TPA3255 EVM negative output terminal to
OUTB (BLACK) and AP analog input channel A negative terminal.
• Connect right channel speaker/power resistor load (4–8 Ω) to TPA3255 EVM positive output terminal
to OUTC (RED) and AP analog input channel B positive terminal.
• Connect right channel speaker/power resistor load (4–8 Ω) to TPA3255 EVM negative output terminal
to OUTD (BLACK) and AP analog input channel B negative terminal.
• Be careful not to mix up PVDD, OUTA, and OUTB terminals, since the colors are the same (RED).
• For single-ended stereo inputs, connect AP channel A XLR to RCA male jacks to female RCA jacks
input A/AB (RED) and AP channel B XLR to RCA male jacks to female RCA jacks input C/CD (WHITE)
and set J4 and J19 jumper positions to SE.
• For differential stereo inputs, connect positive RCA male jacks to female RCA jacks input A/AB
(RED) and input C/CD (WHITE) and connect negative RCA male jacks to female RCA jacks input B
(BLUE) and input D (BLACK) and set J4 and J19 jumper positions to DIFF.
• Power up power supply once all the connections are made correctly and the 3.3-V and12-V LEDs
(GREEN) will illuminate.

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• Set S1 to the NORMAL position.
• CLIP_OTWz (ORANGE) and FAULTz (RED) LEDs should be off, if the audio source is off.
NOTE: J3/J10 and J18/J15 can be used for differential inputs to INA/INB and INC/IND, respectively.
Using a smart phone, tablet, or PC with headphone to RCA cable, audio streaming via headphone jack
can begin once the EVM is powered up correctly with jumpers in their default state. Start the media player
of your choice and enjoy the enhanced audio performance TPA3255 provides as a quick check of the
setup.

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4 Using TPA3255EVM in Different Output Configurations
The TPA3255EVM can be configured for four different output operations. The 2.0 BTL configuration is the
default set up of the TPA3255EVM described in Section 3.3. The remaining three configurations are 2.1
BTL plus two single-ended (SE) outputs, 0.1 PBTL output, and 4.0 single-ended (SE) outputs.
Table 4. Mode Selection Pins
Mode Pins Input Mode Output Configuration Description
M2 M1
0 0 2N + 1 2 × BTL Stereo BTL output configuration
0 1 2N/1N + 1 1 × BTL + 2 × SE 2.1 BTL + SE mode
1 0 2N + 1 1 × PBTL Paralleled BTL configuration. Connect INPUT_C and INPUT_D to
GND.
1 1 1N + 1 4 × SE Single-ended output configuration
4.1 BTL Plus Two SE (2.1) Operation
Configure the EVM as follows for 2 SE + 1 BTL operation:
Table 5. 2 SE + 1 BTL Default Jumper States
Jumper Setting Comment
J29 IN PVDD to 15-V BUCK
J31 IN 12-V LDO to 12-V TERM
J32 IN 3.3-V LDO to 3.3-V TERM
J33 IN 3.3-V LDO to 3.3-V TERM
J21 IN CSTART SE
J16 3 to 4 MASTER MODE
J5 1 to 2 M1 – 2XSE + BTL
J6 2 to 3 M2 - 2XSE + BTL
J22 IN OUTA CAP SHUNT
J23 IN OUTB CAP SHUNT
J24 OUT OUTC CAP SHUNT
J25 OUT OUTD CAP SHUNT
J26 2 to 3 INC SELECT
J27 2 to 3 IND SELECT
J7 OUT PBTL SELECT INC
J8 OUT PBTL SELECT IND
J10 OUT INC/D DIFF INPUT
J12 OUT INC/D DIFF INPUT
J4 1 to 2 INA/B SE INPUT
J19 1 to 2 INC/D SE INPUT
• Set J6 to L and J5 to H.
• Connect left (stereo) speaker/power resistor load (2–4 Ω) positive terminal to OUTC and remove
jumper J24.
• Connect right (stereo) speaker/power resistor load (2–4 Ω) positive terminal to OUTD and remove
jumper J25.
• Connect subwoofer (mono) speaker/power resistor load (4–8 Ω) positive terminal to OUTA and
negative terminal to OUTB.
• Set J19 jumper position to DIFF.
• Connect left (stereo) channel input to female RCA jack input C/CD (WHITE) for OUTC speaker.

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• Connect right (stereo) channel input to female RCA jack input D (BLACK) for OUTD speaker.
• For single-ended subwoofer (mono) input, connect RCA male jack to female RCA jack input A/AB
(RED) and set J4 jumper positions to SE.
• For differential subwoofer (mono) inputs, connect positive RCA male jack to female RCA jack input
A/AB (RED) and connect negative RCA male jack to female RCA jack input B (YELLOW) and set J4
jumper positions to DIFF.
NOTE: OUTC and OUTD are the single-ended output channels and OUTA and OUTB are the BTL
channel for 2.1 operations.
4.2 PBTL (0.1) Output Operation
Configure the EVM as follows for PBTL operations:
Table 6. PBTL Default Jumper States
Jumper Setting Comment
J29 IN PVDD to 15-V BUCK
J31 IN 12-V LDO to 12-V TERM
J32 IN 3.3-V LDO to 3.3-V TERM
J33 IN 3.3-V LDO to 3.3-V TERM
J21 IN CSTART SE
J16 3 to 4 MASTER MODE
J5 2 to 3 M1 – PBTL
J6 1 to 2 M2 – PBTL
J22 IN OUTA CAP SHUNT
J23 IN OUTB CAP SHUNT
J24 IN OUTC CAP SHUNT
J25 IN OUTD CAP SHUNT
J26 2 to 3 INC SELECT
J27 2 to 3 IND SELECT
J7 2 to 3 PBTL SELECT INC – GND
J8 2 to 3 PBTL SELECT IND – GND
J10 OUT INC/D DIFF INPUT
J12 OUT INC/D DIFF INPUT
J4 1 to 2 INA/B SE INPUT
J19 1 to 2 INC/D SE INPUT
• Set J6 to H and J5 to L.
• Connect speaker/power resistor (2–4 Ω) positive terminal to OUTA and OUTC (OUT A and C shorted).
• Connect speaker/power resistor (2–4 Ω) negative terminal to OUTB and OUTD (OUT B and D
shorted).
• Install PBTL jumpers J7 and J8 (pulls input C and input D to GND).
• For single-ended mono input, connect RCA male jack to female RCA jack input A/AB (RED) and set
J4 jumper positions to SE.
• For differential mono inputs, connect positive RCA male jack to female RCA jack input A/AB (RED)
and connect negative RCA male jack to female RCA jack input B (YELLOW) and set J4 jumper
position to DIFF.
NOTE: INA and INB are the inputs for PBTL and INC and IND are grounded for PBTL operation.