Infineon MERUS MA2304DNS User manual

User Manual Please read the sections “Important notice” and “Warnings” at the end of this document V 1.0
www.infineon.com/merus 1 2022-08-26
UM_2204_PL88_2206_163320
User manual for MA evaluation boards
MA2304DNS/MA2304PNS
About this document
Scope and purpose
This document describes the use and operation of the EVAL_AUDIO_MA2304xNS evaluation kit (EVK). The
MA2304xNS EVK is an evaluation and demonstration kit for MA2304DNS and MA2304PNS proprietary multilevel
amplifiers.
Intended audience
Audio amplifier design engineers.
Attention: Please read this user manual before operating the board. When powering up the board, make
sure to follow the instructions in the “MA2304xNS start-up sequence” section.
Stuck or in need of help?
Support for Infineon’s class D audio portfolio can be found quickly and easily by visiting the Class D Audio
Amplifier IC Forum or by visiting community.infineon.com. The community forum features members of the
audio applications team that are ready to provide timely support, helping you get your designs done quickly,
reliably, and right the first time.
Safety precautions
Note: Please note the following warning regarding hazards associated with development systems.
Table 1 Safety precautions
Caution: The evaluation or reference board contains parts and assemblies sensitive to
electrostatic discharge (ESD). Electrostatic control precautions are required when
installing, testing, servicing or repairing the assembly. Component damage may result
if ESD control procedures are not followed. If you are not familiar with ESD control
procedures, refer to the applicable ESD protection handbooks and guidelines.

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Table of contents
Table of contents
About this document....................................................................................................................... 1
Safety precautions.......................................................................................................................... 1
Table of contents............................................................................................................................ 2
1Overview............................................................................................................................... 3
1.1 Board features and audio performance .................................................................................................3
1.2 EVK device type .......................................................................................................................................3
2Setup guide ........................................................................................................................... 4
2.1 EVK connections and interfaces .............................................................................................................5
2.1.1 EVAL_AUDIO_MA2304xNS board.......................................................................................................5
2.1.2 Interface boards.................................................................................................................................6
2.1.3 EVK headers and connectors .............................................................................................................7
2.2 Notes on the digital I/O breakout header...............................................................................................9
3Operating the demonstration board........................................................................................10
3.1 Recommended operating conditions...................................................................................................10
3.2 Toggle switches.....................................................................................................................................10
3.3 Firmware flash for the USB MCU...........................................................................................................10
3.4 Speaker load..........................................................................................................................................12
3.5 MERUS™ amplifier tool..........................................................................................................................13
3.6MA2304xNS start-up sequence .............................................................................................................13
4Measurement methods ..........................................................................................................14
5Schematic ............................................................................................................................16
5.1 Amplifier page .......................................................................................................................................16
5.2 MCU page...............................................................................................................................................17
6PCB layout............................................................................................................................18
7Bill of materials.....................................................................................................................21
Revision history.............................................................................................................................24
Disclaimer.....................................................................................................................................25

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Overview
1Overview
The demonstration board EVAL_AUDIO_MA2304xNS is an evaluation and demonstration board for MERUS™
audio’s MA2304DNS and MA2304PNS amplifiers.
It contains digital input/output (I/O) and a variety of output and setup/selection features. It also contains one
onboard buck power supply generator (1.8 V/3.3 V selectable) so only one external power supply (PVDD) is
necessary.
The board can be used for evaluating or demonstrating key features/advantages of the MERUS™ technology:
•Energy efficiency
−Power losses at typical audio listening levels
−Idle power loss
•Adaptive power management system
•No output filter components
−Solution cost and size reduction
•Audio performance
−THD performance and audio quality
1.1 Board features and audio performance
•Number of audio channels 2 (BTL) or 1 (PBTL)
•Audio input format Digital (I2S, LJF, RJF or TDM)
•Typical supply voltage 18 V (PVDD)
•Output noise level 52 µVRMS (high audio performance mode)
•Dynamic range 106 dB (high audio performance mode)
•Idle consumption at PVDD = 18 V 61 mW (low power consumption mode)
•Efficiency
−1 W, 8 ΩMore than 79 percent
−Full-scale, 8 ΩMore than 90 percent
Note: Idle consumption is the sum of output stage (PVDD) current, VDD, and VDD_IO supply current. As all
the supplies are tied to PVDD, the efficiency of the buck-converter should be taken into account
when measuring idle current consumption directly from PVDD. Features on the EVK make it
possible to break the input and output of the buck converters for these purposes (see Table 3).
Please refer to the MA2304xNS device datasheet for exact current figures.
1.2 EVK device type
The type of device –MA2304DNS/MA2304PNS –is printed on the top of the EVK, and is also stated on the serial
number label on the bottom side of the EVK PCB.

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Setup guide
2Setup guide
The following is included in the MA2304xNS evaluation kit:
1. An EVAL_AUDIO_MA2304xNS board
2. I2S interface boards: analog in, S/PDIF coax and S/PDIF optical
3. A micro USB cable
4. A 22 µH power inductor
Additional equipment required for operation and evaluation:
1. A 10 to 20 V DC power supply capable of driving 6 A (BTL) or 12 A (PBTL)
2. Loudspeaker and speaker wires, as shown in Figure 1
In addition, for datasheet spec testing, as shown in Figure 1:
1. A 2 to 8 Ωresistor load
2. An audio analyzer with a class-D measurement filter
OR
Figure 1 Setup for “speaker test” or “datasheet spec test”
SPK
SPK+
SPK-
SPK+
SPK-
22µH
 
Filter
Audio
Analyzer

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Setup guide
2.1 EVK connections and interfaces
The MA2304xNS EVK includes the main EVAL_AUDIO_MA2304xNS board and three interface boards.
2.1.1 EVAL_AUDIO_MA2304xNS board
The board features MA2304xNS silicon, digital I/O headers, enable and mute switches, speaker terminals,
power supply terminal blocks and a USB port.
Figure 2 EVAL_AUDIO_MA2304xNS board (top view)

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Setup guide
2.1.2 Interface boards
Three interface boards are included: analog in, S/PDIF coax and S/PDIF optical. These are plugged in to the J1
digital I/O breakout header for simple evaluation.
Figure 3 Interface boards
There is no need to configure the MA2304xNS when using these interface boards, as its digital audio output
format matches the MA2304xNS defaults.
Note that the interface boards are not compatible with a 1.8 V supply. When using the onboard buck converter,
ensure that the MA2304xNS board’s VDD_SEL jumper is configured for 3.3 V (pins 1 and 2).
Interface board input/output specifications are provided in Table 2.
Table 2 Interface board I/O specifications
Interface board
Input
Output
Analog in1
3.5 mm (1/8 in.) stereo TRS jack
2.1 VRMS full-scale
I2S, 24-bit serial audio at 3.3 V
SCK = 64 x WCK
WCK = 48 kHz
S/PDIF coax
RCA jack
0.2 V minimum, 5 V tolerant
32 to 96 kHz support
I2S, 24-bit serial audio at 3.3 V
SCK = 64 x WCK
WCK = 32 to 96 kHz
S/PDIF optical
Optical input jack
32 to 96 kHz support
I2S, 24-bit serial audio at 3.3 V
SCK = 64 x WCK
WCK = 32 to 96 kHz
1Noise measurements and other specs will show degraded performance when using the analog in interface board.

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2.1.3 EVK headers and connectors
The following table provides a description of each jumper, header, switch and test point. Defaults are shown in
the “Comment”column.
Table 3 EVK headers and connectors
Name
Description
Comment
J_MSEL
Selects amplifier output mode between PBTL (L) and BTL(H)
Default:
BTL(H)
JI2C_ADD
AD1
AD0
These headers select the I2C slave address (see Table 4)
Default:
I2C address 0b0100000
AD1 and AD0 both
jumpered low (GND)
JVDD_IO
Sets VDD_IO source as:
VDD_REG onboard supply (pins 1 and 2)
VDD 1.8 V/3.3 V onboard supply (pins 2 and 3)
Default:
VDD (pins 2 and 3)
J_VDD
Sets VDD source as:
PVDD onboard supply (pins 1 and 2)
VDD 1.8 V/3.3 V onboard supply (pins 2 and 3)
Default:
VDD (pins 2 and 3)
J3V3SW
Sets VDD_MCU source as:
VDD 1.8 V/3.3 V onboard supply (pins 1 and 2)
VDD_LDO onboard supply (pins 2 and 3)
Default:
LDO (pins 2 and 3)
VDD_SEL
Sets the onboard buck converter output as:
3.3 V (pins 1 and 2)
1.8 V (pins 2 and 3)
Default:
3.3 V (pins 1 and 2)
VDD_SW
Provides the option to measure PVDD current into the buck converter
Default:
Jumpered
VDD_ON
Provides the option to measure the buck converter output current
Default:
Jumpered
Jdebug
For normal operation, place a jumper on pins 7 and 8
Default:
Pins 7 and 8 jumpered
J1
Digital I/O breakout header. Refer to Section 2.2 for details.
I/O pins. Do not jumper.
J2
Interface board connector
I/O pins. Do not jumper.
SW_ENABLE
Controls the amplifier’s ENABLE pin. Sets the amplifier into enabled
state when set to on.
Default:
Off
SW_MUTE
Controls the amplifier’s NMUTE pin. Mutes the amplifier when set to
mute.
Default:
Mute
SW_MCU_RESET
Places the onboard MCU into reset state while pressed
P_SPK_L
OUT0x speaker connection
Three-way screw terminal
with positive and negative
speaker outputs. Center
terminal = GND.
P_SPK_R
OUT1x speaker connection
Three-way screw terminal
with positive and negative
speaker outputs. Center
terminal = GND.
TP_OUT0A
Direct connection to device output node OUT0A
Output measurement pin

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Setup guide
Name
Description
Comment
TP_OUT0B
Direct connection to device output node OUT0B
Output measurement pin
TP_OUT1A
Direct connection to device output node OUT1A
Output measurement pin
TP_OUT1B
Direct connection to device output node OUT1B
Output measurement pin
TP_ADC
AUX_ADC input test point
TP_GND6
TP_GND7
TP_GND8
Ground test points
TP_GND
TP_GND2
TP_GND3
TP_GND4
TP_GND5
Ground-connected mounting holes
Table 4 I2C address decoding (JI2C_ADD)
I2C device address
AD1
AD0
7-bit I2C address
0x20
L
L
0b0100000
0x21
L
H
0b0100001
0x22
H
L
0b0100010
0x23
H
H
0b0100011

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Setup guide
2.2 Notes on the digital I/O breakout header
The digital I/O breakout header (J1) provides access to audio and control signals (I2S and I2C, respectively) as
well as several MA2304xNS GPIO pins and the onboard VDD supply (3.3 or 1.8 V). The J1 header is meant for use
with the interface boards, and/or external connections (external I2S, MCU, etc.) for measurements and
debugging. The J2 header contains exactly the same signals as J1 but can be used for monitoring the I/O digital
signals.
The MA2304xNS acts as an I2S slave, accepting SCK (bit clock) and WC (word clock) as inputs, with SCK = 64 x WC
as default.
Table 5 Digital I/O breakout header
Pin
Signal
Signal
Pin
20
GND
/AMP_ERR
19
18
GND
/AMP_CLIP
17
16
GND
I2S_DO
15
14
GND
I2S_WC
13
12
GND
I2S_SCK
11
10
GND
I2S_DI
9
8
GND
I2C_SDA
7
6
GND
I2C_SCL
5
4
GND
/MUTE
3
2
3V3
EN
1

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Operating the demonstration board
3Operating the demonstration board
3.1 Recommended operating conditions
Table 6 Recommended operating conditions
Parameter
Minimum
Nominal
Maximum
Unit
PVDD
10
18
20
V
Output peak current (BTL)
Output peak current (PBTL)
6.0
12.0
A
A
3.2 Toggle switches
The board has two MA2304xNS-related toggle switches, as shown in Table 7. The toggle switches have the
following functions:
Table 7 Switch function
Switch
Function
SW_ENABLE
Off/on (default set to “off”)
SW_MUTE
Mute/unmute (default set to “mute”)
3.3 Firmware flash for the USB MCU
The evaluation board’s MCU firmware can easily be updated through USB. The latest firmware bin file can be
obtained by downloading and installing the latest MERUS™ amplifier tool GUI for the MA2304xNS. The firmware
bin file is located in the “[Installation folder]\firmware” folder.
Follow the subsequent steps to flash the MCU:
1. Configure the evaluation board jumpers and switches as described in Table 3.
2. Set the Jdebug jumper to the third column from left to right (connecting pin 5 and 6):
Figure 4 Configuring the Jdebug header for firmware flash
3. Connect a USB cable to the evaluation board:
Figure 5 Connecting a USB cable to the evaluation board

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Operating the demonstration board
4. Open Windows explorer and then the drive called “CRP DISABLD”. Delete the file “firmware.bin”:
Figure 6 Deleting the contents of the “CRP DISABLD” drive
5. Open another explorer window and browse to the software installation folder, typically
“C:\Users\[User]\Infineon\Tools\Merus-Amplifier-Tool”. Copy the .bin file from the firmware folder to the
“CRP DISABLD” drive. In this example the .bin file is called “firmware.bin”, but it could have other filenames.
Figure 7 Copying “firmware.bin” to the “CRP DISABLD” drive
6. Move the Jdebug header back to the second column from left to right (connecting pin 7 and 8):
Figure 8 Configuring the Jdebug header for normal operation
7. Close Windows explorer and disconnect the USB cable.
Figure 9 Disconnecting the USB cable from the evaluation board
8. The MCU firmware update is now complete.

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Operating the demonstration board
3.4 Speaker load
The demonstration board is configured as a filterless amplifier. This means that no LC filter is placed between
the amplifier outputs and the load. In normal use the amplifier relies on the inherent inductance of the
loudspeaker, so no extra inductance is needed.
Inductors for use in series with power resistors are included with the demonstration board. These can be used
when making any measurements without a real loudspeaker as the load, and having no external low-pass filter
(LPF) in front of the audio analyzer input section.
Please note that many audio measurement analyzers do not perform correctly when connected directly to a
filterless amplifier output. Please refer to Section 4 for more information on measurement methods.

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Operating the demonstration board
3.5 MERUS™ amplifier tool
The demonstration board is used with PC graphical user interface (GUI) software to control the MA2304xNS
device.
The MA2304xNS can play audio by default without configuration, but to take advantage of the many features
the chip offers it is necessary to configure the device.
Refer to the MERUS™ amplifier tool user manual for details on how to install and use this software.
Figure 10 MA2304DNS GUI main window
3.6 MA2304xNS start-up sequence
Follow this (recommended) sequence to start the board:
1. Make sure toggle buttons are in “off” and “mute” positions.
2. Connect all cables (speakers/load, USB and power) to the EVK.
3. Connect an external I2S digital audio source to the EVK digital I/O header (J1). The EVK default I/O voltage is
3.3 V.
4. Turn on the PVDD power supply.
5. Make sure the I2S clocks are present before enabling the amplifier.
6. Start board by setting the SW_ENABLE toggle switch to the “on” position.
7. Start playing sound by setting the SW_MUTE toggle switch to the “unmute” position.
Mute and turn off the PVDD power supply when finished.

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Measurement methods
4Measurement methods
Setting up a reliable measurement configuration for the MA2304DNS or the MA2304PNS takes a little more
effort than for linear amplifiers, and even “regular” switching amplifiers. This is mainly because the MA2304xNS
is a filterless amplifier, which means it does not require an external (usually expensive and bulky) LC filter to
remove switching residuals. The filterless application is enabled by the MERUS™ audio multilevel technique,
which ensures the switching residual is orders lower compared to “regular” switching amplifiers. For more
information on the multilevel switching technique, please refer to the datasheet.
To obtain reliable measurement results, the MA2304xNS devices require a separate external LPF in front of the
input stage of the audio analyzer. Most audio analyzers are bandwidth-limited at their input stage, which
means they cannot follow the rapid changes of the amplifier’s output stage. This can result in inaccurate and
high THD+N measurements.
Figure 11 shows the recommended measurement setup. The setup shows a LPF stage (AUX-0025) in front of
the audio analyzer (APx525 with the serial interface I/O option installed). In this case the measurement setup
has been built around Audio Precision hardware, but this can also be some other audio analyzer hardware.
Please note that it is recommended to use a balanced input measurement configuration.
22µH
 
Audio Analyzer
ChA IN
ChB IN
Audio Precision APx525
Analog Input External Class-D Filter
ChA IN
ChB IN
ChA OUT
ChB OUT
Audio Precision AUX-0025
Digital Serial
Bit Clock
Frame Clock
Data Out
I2S_SCK
I2S_WS
I2S_DI
22µH
 
OUT+
OUT-
OUT+
OUT-
BTL Ch1
BTL Ch0
Serial I/O
MA2304xNS
Device Under Test (DUT)
Figure 11 Recommended audio measurement setup

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Measurement methods
Figure 12 shows an example measurement setup using an 8 Ω/22 µH load, similar to the setup shown in Figure
11.
Figure 12 Audio measurement setup example
Figure 13 shows an example dynamic range measurement performed with the previous measurement setup.
Figure 13 Dynamic range measurement example

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Schematic
5Schematic
5.1 Amplifier page
Figure 14 Amplifier page

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Schematic
5.2 MCU page
Figure 15 MCU page

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PCB layout
6PCB layout
Figure 16 PCB layout (top composite x-ray view)
Figure 17 PCB layout (top layer)

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PCB layout
Figure 18 PCB layout (layer 1)
Figure 19 PCB layout (layer 2)

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PCB layout
Figure 20 PCB layout (bottom layer)
Figure 21 PCB layout (mirrored bottom composite x-ray view)