Raspberry Pi HAT offers up to 40W class D amp
May 21, 2020 — by Eric Brown 9,505 views
Infineon’s $37 MERUS audio amplifier HAT for the Raspberry Pi incorporates a MERUS MA12070P multilevel class D amp with up to 40W peak power and 48KHz/24bit music playback.
There are plenty of audio HATs for the Raspberry Pi with built-in amplifiers that are perfectly suited for various IoT applications, but not many you would want to use for listening to music without your headphones on. Infineon Technologies may have the solution with a new HAT that it claims is the world’s first fully self-contained Raspberry Pi audio amplifier HAT board with HD audio at boom box power levels in a small form factor.
MERUS audio amplifier HAT (KIT_40W_AMP_HAT_ZW) alone (left) and with Raspberry Pi Zero W
(click images to enlarge)
The KIT_40W_AMP_HAT_ZW board, which we refer to here by its nickname “MERUS audio amplifier HAT,” incorporates Infineon’s MERUS MA12070P multilevel class D amp. Compatible with the Raspberry Pi 3 and 4, as well as the Raspberry Pi Zero W, the partial HAT (pHAT) sized add-on is designed for active speakers with wireless music streaming.
The MERUS audio amplifier HAT supports up to 40W instantaneous peak power at 4 Ohm using the standard RPi 5V/2.5 A USB RPi power supplies. The HAT provides 48KHz/24bit music playback.
— ADVERTISEMENT —
Thanks to proprietary MERUS multilevel technology, the MA12070P amp enables filterfree amplifier designs that do not require a filter-coil at the output filter, thereby reducing the BOM cost and PCB area. For portable use, the HAT supports up to 20 hours with a 6700mAh power bank.
The MERUS audio amplifier HAT is compatible with Raspbian and common Linux audio applications such as Volumio, moOde Audio, and JustboomPlayer. Extensive documentation is available for setup and configuration. The HAT supports dual-channel bridge-tied load (BTL) or single-channel parallel bridge-tied load (PBTL) configurations for multi-room, TWS, or subwoofer applications.
Further information
The MERUS audio amplifier HAT (KIT_40W_AMP_HAT_ZW) is available for $37.38 plus $5.00 standard global shipping. More information may be found in Infineon’s announcement and product/shopping page.
That’s pretty amazing that they have managed to defeat physics with this. The 5V/2.5A power supply is capable of 12.5W and they can get an output of 40W out of that.
No magic. 40W instantaneous peak power. Peak, not continuous.
The chip can indeed deliver the declared power but must be supplied with much higher supply voltage on the switching supply line (up to 26V) and fitted with a small heatsink. The really good thing about this chip is that there is a i2s DAC on board, which is a godsend especially for older raspberries due to their PWM audio abysmal quality output. This will probably be very easy to adapt to other vendors Linux boards as well; just by routing the right signals and porting the driver.
Thanks. Missed that it was instantaneous. No mention of RMS output seems a bit strange.
2x30W continuous output power (RL = 8Ω at 22V, PMP4, 10% THD+N level)