Infineon MERUS MA120 Series User manual

Application Note Please read the Important Notice and Warnings at the end of this document V 1.0
www.infineon.com/merus page 1 of 28 2019-04-28
UM_1902_PL88_1902_171735
User manual for MERUSTM MA120xxx reference
boards
P100002130 REF_AUDIO_MA12040
P100002140 REF_AUDIO_MA12040P
P100002170 REF_AUDIO_MA12070
P100002180 REF_AUDIO_MA12070P
About this document
Scope and purpose
This is a reference and demonstration board for MA12040, MA12040P, MA12070 and MA12070P proprietary
multi-level amplifiers.
This application note describes the functionality and set-up of the reference design (Sections 2 and 3). It also
includes a schematic, PCB layout, BOM and a discussion of circuit design considerations (Section 4).
Measurement results (Section 5) show high performance in audio and efficiency parameters, as well as good
thermal characteristics. Testing included a frequency sweep, output power sweep and electromagnetic
interference tests. Finally, Appendix A provides sample code that demonstrates basic I2C communication using
Arduino UNO.
Intended audience
Audio amplifier design engineers, audio system engineers and audio software engineers.

Application Note 2 of 28 V 1.0
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User manual for MA120xxx reference boards
Board overview
Table of contents
About this document....................................................................................................................... 1
Table of contents............................................................................................................................ 2
1Board overview...................................................................................................................... 3
1.1 General board specifications..................................................................................................................4
1.2 RFB device type .......................................................................................................................................4
1.3 Set-up guide ............................................................................................................................................4
1.4 Board configuration................................................................................................................................6
1.5 Device configuration through I2C............................................................................................................7
2Schematic, layout and design considerations............................................................................ 8
2.1 BOM........................................................................................................................................................11
2.2 Design considerations...........................................................................................................................12
3Measurement results.............................................................................................................13
3.1 Frequency sweep...................................................................................................................................13
3.2 Output power sweep.............................................................................................................................15
3.3 Output spectrum...................................................................................................................................16
3.4 Power consumption and efficiency......................................................................................................17
3.5 EMI radiated measurements.................................................................................................................20
3.5.1 EMI measurement setup..................................................................................................................20
3.5.2 EMI measurement results ................................................................................................................20
4Appendix A –sample code ......................................................................................................25
Revision history.............................................................................................................................27

Application Note 3 of 28 V 1.0
2019-04-28
User manual for MA120xxx reference boards
Board overview
1Board overview
The reference board (RFB) is a reference and demonstration board for Infineon’s MA12040, MA12040P, MA12070
and MA12070P amplifiers. See the board in Figure 1 with MA12070 mounted.
It contains a variety of digital/analog input, output and set-up/selection features. It also contains one on-board
power supply (5 V buck converter), so only one external power supply (PVDD) is necessary.
Figure 1 Reference board PCB
The board can be used for evaluating or demonstrating key features/advantages of the MERUSTM Audio
technology:
Energy efficiency
−Power losses under normal user operating conditions (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
Fast product protyping
−All design files are available
−Guides as reference for product design-in

Application Note 4 of 28 V 1.0
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User manual for MA120xxx reference boards
Board overview
1.1 General board specifications
Number of audio channels 2 x BTL or 1 x PBTL
Audio input format:
oMA12040 and MA12070 Analog
oMA12040P and MA12070P Digital (I2S)
Supply voltage range MA12040(P) 5 to 18 V
Supply voltage range MA12070(P) 5 to 26 V
Maximum output current per channel MA12040(P) 6 A
Maximum output current per channel MA12070(P) 8 A
Output power capability at 18 V PVDD:
oPeak 2 x 40 W sine 1 kHz (RMS) into 4 Ω(10 percent THD + N)
oPeak 2 x 20 W sine 1 kHz (RMS) into 8 Ω(10 percent THD + N)
oContinuous 2 x 9.0 W sine 1 kHz (RMS) into 4 Ω(less than 0.08 percent THD + N)
Output power capability at 26 V PVDD:
oPeak 2 x 80 W sine 1 kHz (RMS) into 4 Ω(10 percent THD + N)
oPeak 2 x 40 W sine 1 kHz (RMS) into 8 Ω(10 percent THD + N)
oContinuous 2 x 9.0 W sine 1 kHz (RMS) into 4 Ω(less than 0.02 percent THD + N)
Amplifier gain (MA12040 and MA12070 only) 20 dB or 26 dB (register configurable)
Output integrated noise:
oMA12040 and MA12070 Less than 100 µVrms (AW)
oMA12040P and MA12070P Less than 150 µVrms (AW)
Dynamic range:
oMA12040 and MA12070 More than 100 dB
oMA12040P and MA12070P More than 96 dB
Idle current consumption at 18 V PVDD:
oMA12040 and MA12070 Less than 16 mA
oMA12040P and MA12070P Less than 19 mA
Note:Idle consumption is the sum of output stage current and 5 V supply current. As all the supplies are tied to
PVDD, the efficiency of the buck converter 5 V should be taken into account when measuring idle current
consumption directly from PVDD. Please refer to the MA120xx/P device datasheet for exact current figures.
1.2 RFB device type
The type of device (MA12040, MA12040P, MA12070 and MA12070P) on the RFB is printed on the top of the
device, and is also stated on the serial number label placed on the bottom side of the PCB.
1.3 Set-up guide
The RFB works out of the box with speakers, input source and power connected. No external configuration or
set-up is needed for quick start-up.

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User manual for MA120xxx reference boards
Board overview
Figure 2 shows the top view of the board assembly. The board has following key features, which are indicated by
corresponding numbers marked with red.
1. PVDD power connector: connect PVDD 5 V to 18 V for MA12040(P) or connect PVDD 5 V to 26 V for
MA12070(P)
2. BTL output connection channel 0
3. BTL output connection channel 1
4. PAUDIO: signal input connector:
oFor MA12070 devices:
Pin 5: AN0A –analog input A channel 0
Pin 4: AN0B –analog input B channel 0
Pin 3: GND
Pin 2: AN1A –analog input A channel 1
Pin 1: AN1B –analog input B channel 1
oFor MA12070P devices:
Pin 5: SCK –I2S bit clock
Pin 4: WS –I2S word clock
Pin 3: GND
Pin 2: SD0 –I2S audio data
Pin 1: CLK –I2S master clock
5. PCTRL external communication:
Pin 5: SCL –I2C clock
Pin 4: SDA –I2C data
Pin 3: GND
Pin 2: /ENABLE –enable or disable the amplifier
Pin 1: /MUTE –mute or unmute the amplifier
6. MA12040, MA12040P, MA12070 or MA12070P Eximo multi-level amplifier IC
7. Buck regulator: TPS62175 –for generating 5 V supply

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User manual for MA120xxx reference boards
Board overview
Figure 2 Schematic top view of component and connector assembly
1.4 Board configuration
The board is shipped with a default configuration for automatic start-up, two channels of BTL output, and
default internal register settings. It is however possible to operate the board in different modes. The following
configurations are possible:
BTL or PBTL output configuration:
oBTL: RPBTL unmounted; RBTL mounted
oPBTL: RPBTL mounted; RBTL unmounted
External control of the /ENABLE pin: RENABLE unmounted
External control of the /MUTE pin: RMUTE unmounted
The board can carry MA12040(P) or MA12070(P) devices. Depending on which device is placed, the following
configurations apply for:
MA12040 and MA12070:
oCAPIN0A, CAPIN0B, CAPIN1A and CAPIN1B are mounted
oRCLK_ANA mounted; RCLK_DIG unmounted
oRCLK unmounted
MA12040P and MA12070P:
oCAPIN0A, CAPIN0B, CAPIN1A and CAPIN1B replaced by jumpers
oRCLK_ANA unmounted; RCLK_DIG mounted
oRCLK mounted

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User manual for MA120xxx reference boards
Board overview
1.5 Device configuration through I2C
Multi-level technology offers the possibility to optimize for audio performance, efficiency or EMI. Depending on
the application, typically one parameter is more important than the others. The amplifiers offer the flexibility to
make this design trade-off by the use of different optimal modes (Power Mode Profiles or PMP), selected
through internal register settings. The RFB uses the MA120XXX in the default PMP0, which optimizes the
amplifier operation for highest power efficiency in the low to mid output power region. For a complete
overview of device configurations, please refer to the datasheets.
I2C is used to read and write the internal registers. SCL and SDA can be accessed through Pin 5 and Pin 4 on the
PCTRL header (see previous section). Figure 3 shows how to set up I2C communication using an Arduino UNO.
Sample code for I2C set-up can be found in Apendix A –sample code.
Figure 3 Arduino I2C communication to the RFB
Pull-up

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User manual for MA120xxx reference boards
Schematic, layout and design considerations
2Schematic, layout and design considerations
Figure 4 Reference board schematic

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User manual for MA120xxx reference boards
Schematic, layout and design considerations
Figure 5 Top side of the PCB layout

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User manual for MA120xxx reference boards
Schematic, layout and design considerations
Figure 6 Bottom side of the PCB layout
The RFB is cost optimized. The cost of one module including PCB, components and assembly is estimated to be
$2.15 at a volume of 1000 pieces. The price of the MA120xx(P) amplifier depends on the volume and part. For
performance optimization see the application note “EMC output filter recommendation” or contact Infineon.

Application Note 11 of 28 V 1.0
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User manual for MA120xxx reference boards
Schematic, layout and design considerations
2.1 BOM
Table 1 RFB BOM
Designator
Description
Manufacturer
Part number
Quantity
C0A, C0B, C1A, C1B
CAP, 1000 pF, ±10 percent, X7R, 50 V,
0402
TDK
C1005X7R1H102K050BA
4
CAPIN0A, CAPIN0B, CAPIN1A,
CAPIN1B
CAP, 1 µF, ± 10 percent, X5R, 10 V,
0402
Multicomp
MC0402X105K100CT
4
CAVDD0, CCDC, CCREF, CFDC,
CGD0, CGD1, CVGDC, DVDD0
CAP, 1 µF, ± 10 percent, X7R, 25 V,
0603
Multicomp
MC0603X105K250CT
8
CF0A0, CF0A1, CF0B0, CF0B1,
CF1A0, CF1A1, CF1B0, CF1B1
CAP, 10 µF, ± 10 percent, X5R, 25 V,
0805
TDK
TMK212BBJ106MG-T
8
CFGD, CGD0N0, CGD1N0,
CPVDD0A, CPVDD1A
CAP, 0.1 µF, ± 10 percent, X7R, 50 V,
0603
Multicomp
MC0603B104K500CT
5
CGD0N1, CGD1N1, CPVDD0B,
CPVDD1B
CAP, 1 µF, 50 V, ± 10 percent, X5R,
0805
Multicomp
MC0805X105K500CT
4
CIN0, CIN1
CAP, 0.022 µF, ± 10 percent, X7R, 50
V, 0402
Murata
GRM155R71H223KA12D
2
CINBUCK
CAP 2.2 µF 50 V ±10 percent, 0805
Taiyo Yuden
UMK212BB7225KG-T
1
COUTBUCK
CAP 22 µF 50 V ±10 percent 0805
Murata
GRM21BR61A226ME51L
1
CSUP1, CSUP2
Electrolytic cap, UWT series, 100 µF,
35 V
Nichicon
UWT1V101MCL1GS
2
L0A, L0B, L1A, L1B
SMD ferrite bead, Z = 56 Ω
Fair-Rite
2512065007Y6
4
LBUCK
SRN4026-150M
Bourns
SRN4026-100M
1
LSUP
SMD ferrite power bead, Z = 47 Ω
Fair-Rite
2743019447
1
RAD00, RAD11, RBTL,
RCLK_ANA, RENABLE, RMUTE,
RPBTL
Jumper 0201 (0603 metric)
Yageo
RC0201JR-070RL
7
RB_FB1
2 M 0.063 W 1 percent 0402 (1005
metric) SMD
Yageo
RC0402FR-072ML
1
RB_FB2
383 K 0.063 W 1 percent 0402 (1005
metric) SMD
Yageo
RC0402FR-07383KL
1
RB_PG
100 K 0.063 W 1 percent 0402 (1005
metric) SMD
Yageo
RC0402FR-07100KL
1
U1
Multi-level Class D amplifier
Infineon
MA120xx
1
U2
TPS62175DQCT
TI
TPS62175DQCT
1

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User manual for MA120xxx reference boards
Schematic, layout and design considerations
2.2 Design considerations
The RFB is elegant because of its small form factor, while still being able to operate at up to 80 W output power
per channel. This is possible due to the multi-level technology of the MA12070 and MA12070P devices.
Thermal considerations:
oPower-efficient operation allows heatsink-free operation because the bottom layer of the PCB
design (connected to the heatsink pad of the IC) is sufficient for cool operating conditions. This
holds when considering playback of real audio signals.
oFigure 5 and Figure 6 show the top and bottom PCB design respectively. It can be seen that all the
component placement and main routing is done on the top layer.
oIt is important to have as little routing as possible on the bottom layer since it needs to be
optimized for thermal heat flow.
oRouting done on the bottom layer is chosen in such a way that it still allows for good thermal heat
flow. In this way, the complete bottom plate can function as a heatsink for the amplifier IC.
oVias placed between bottom and top ground planes add to the copper mass that functions as a
heatsink.
Filterless operation:
oMulti-level technology also significantly reduces out-of-band noise, which allows LC filter-free
operation. Only a small, SMD-sized EMI filter is needed.
oFigure 1 shows the footprint and PCB size it takes. The board size is significantly reduced due to a
small-sized EMI filter compared to a bulky LC filter.
oThe use of an LC filter is also not needed to optimize the efficiency of the amplifier. The speaker’s
inductive behavior is sufficient for efficient operation of the amplifier. This is again enabled by
reduced out-of-band noise of the amplifier.
Buck regulator:
oA buck regulator (TPS62175) has been included in the design to derive a 5 V rail from the PVDD input
rail. 5 V is needed as the core supply voltage for the MA120xx(P). TPS62175 has been chosen to
balance the need for cost, efficiency and size. The current design of the buck regulator generates 5
V from 26 V PVDD with approximately 85 percent efficiency. Efficiency could have been increased by
increasing the inductance, which would have increased the footprint; Infineon opted for a smaller
footprint instead.

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User manual for MA120xxx reference boards
Measurement results
3Measurement results
This section shows the measurement results from tests performed on a reference board, which demonstrate
high audio and efficiency performance and good thermal characteristics.
Measurements include:
Frequency sweep
Output power sweep
Output spectrum
Power consumption and efficiency
EMI
All measurement results were obtained using the following settings:
Device: MA12070
Two-channel BTL configuration
Load: 4 Ω+ 22 μH series inductance
PVDD: 18 V
Gain setting: 20 dB
PMP: default PMP0
Measurements carried out with APx 515 + AUX-0025 input filter
APx uses AES17 brick-wall filter (20 kHz)
3.1 Frequency sweep
Frequency sweeps were carried out with both channels at 1 W output power. To improve the gain drop at 20 Hz,
use larger input capacitors.
Figure 7 Gain vs. frequency
0
5
10
15
20
25
30
35
40
10 100 1000 10000
Gain [dB]
Frequency [Hz]
Channel 1
Channel 2

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User manual for MA120xxx reference boards
Measurement results
Figure 8 THD + N vs. frequency
To improve the THD + N performance use high-performance ferrite beads. See the application note –EMC
output filter recommendations at www.Infineon.com
0,001
0,01
0,1
1
10
100
10 100 1000 10000
THD+N [%]
Frequency [Hz]
Channel 1
Channel 2

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User manual for MA120xxx reference boards
Measurement results
3.2 Output power sweep
Output power sweeps were carried out on both channels with a 1 kHz input signal.
Figure 9 THD + N vs. output power
0,01
0,1
1
10
100
0,001 0,01 0,1 1 10 100
THD+N [%]
Frequency [Hz]
Channel 1
Channel 2

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Measurement results
3.3 Output spectrum
The Figure 10 shows the output spectrum that has been obtained by applying 1 mVrms (1 kHz) input signal to
both channels. This gives an output signal of -40 dBV. The noise floor for these settings is shown in the Figure
10. The integrated, A-weighted noise floor number for both channels is 70 µVrms (AW).
Figure 10 Output FFT spectrum
-160
-140
-120
-100
-80
-60
-40
-20
0
20
40
20 200 2000 20000
Level (dBV)
Frequency (Hz)
Ch0
Ch1

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User manual for MA120xxx reference boards
Measurement results
Figure 11 Scope capture showing 10 mVrms output signal on both channels
3.4 Power consumption and efficiency
Power consumption and efficiency measurements were obtained by using a test signal of 1 kHz and a load of 4
Ωwith 22 μH series inductance. Power consumption was calculated using the RMS method.
Figure 12 Input power as a function of output power
-0,02
-0,016
-0,012
-0,008
-0,004
0
0,004
0,008
0,012
0,016
0,02
0 0,0005 0,001 0,0015 0,002
Level (V)
Time (s)
Ch0
Ch1
0,1
1
10
100
0,00001 0,0001 0,001 0,01 0,1 1 10 100
Input Power (W)
Output Power (W)

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User manual for MA120xxx reference boards
Measurement results
Figure 13 Power loss as a function of output power
Figure 14 Efficiency as a function of output power (log scale)

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User manual for MA120xxx reference boards
Measurement results
Figure 15 Efficiency as a function of output power (linear scale)

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User manual for MA120xxx reference boards
Measurement results
3.5 EMI radiated measurements
3.5.1 EMI measurement setup
AUDIO
SOURCE
LINEAR POWER
SUPPLY
TURN TABLE
EMC chamber
R&S Spectrum
Analyzer
Test PC
Speakers
DEVICE
UNDER
TEST
Figure 16 EMI measurement set-up for radiated emission test
Figure 16 shows the set-up for testing.
Measurement results were obtained under the following conditions:
Linear power supply: 18 V PVDD
Pink noise test signal output power at 20 dB gain = 1 W average output power per channel
Speaker cable length: 10 cm
Amplifier load: 4 Ωspeaker (Visaton FR 10 WP)
EMI filter: Murata ferrite BLE32PN300SN1L + 1 nF capacitor
Pi filter on PVDD –Würth ferrite 74279221100 + 2 x 22 nF capacitor
3.5.2 EMI measurement results
EMI-radiated results were collected for the reference board using four scenarios:
Board was positioned toward the antenna and the antenna was vertical (Figure 17)
Board was positioned toward the antenna and the antenna was horizontal (Figure 18)
Board was positioned perpendicular to the antenna and the antenna was vertical (Figure 19)
Board was positioned perpendicular to the antenna and the antenna was horizontal (Figure 20)