Infineon Announces MERUS™ Brand of Comprehensive Class D Audio Amplifier Solutions

May 03, 2019 by Scott McMahan

Infineon Technologies AG launched its MERUS™ brand, which brings together its existing portfolio of multi-chip modules and discrete audio products under one umbrella.

The brand will promote the belief that the best audio amplifier ICs produce sound in the speakers, but do not heat the surroundings. The audio amplifier ICs should be heard but not seen. And they should be smaller and lighter, not bulky and heavy.

They should also be robust and flexible, not delicate and demanding.

Following these design principles, Infineon is introducing a family of highly power efficient monolithic class D audio amplifier solutions.

Building block for this improved performance is a new technology, the multilevel switching technology for class D audio amplifiers.

Setting a benchmark in the audio market, these class D audio amplifiers positively affects the amplifier evaluation parameters including solution size, power consumption, electromagnetic interference, BOM cost, and of course audio performance. As a result, the company says that up to five levels of output signal modulation becomes feasible.

Compared to their traditional counterparts, multilevel amplifiers use additional on-chip MOSFETs and capacitors to produce outputs with higher signal granularity, such as higher switching frequencies and scalable output signal levels. This higher signal granularity results in a small form factor and virtually no switching loss measurable in idle mode.

Building on the design ideas above, Infineon introduced a family of four integrated multilevel audio amplifiers, the MA12040/P and the MA12070/P in two versions, respectively. They boast power consumption in the 250mW range. For this reason, the audio amplifiers are suited for portable battery powered products and applications with demanding thermal conditions meeting the critical design objectives for modern audio applications.

(Click on the product chart to enlarge)

Traditional class D amplifiers are only efficient at highest music volume levels resulting in high THD, which renders quality less useful for practical implementations. In realistic audio playback scenarios, they consume significantly more input power (about 1W on average) than the first generation of MERUS integrated multilevel audio amplifier ICs, which consume about 0.25W.

The newly introduced audio amplifiers support up to four channels, which can be configured in parallel bridge-tied-load (PBTL), in bridge-tied-load (BTL), or in single-ended (SE) mode. As such, a single IC can output up to 160W peak (16A max) in a single PBTL channel or, for instance, it can be set up as a 2.1 system with 2 x 20W tweeters as SE channels and 1 x 40W woofer speaker as BTL channel. In addition, the products feature an advanced digital power management scheme, low THD+N (0.003 percent) and low EMI emissions.

Multilevel technology allows heatsink-free operation without filters. This technology reduces the bill of materials and overall system costs due to reduced component count and minimized cooling requirements. The MA12040/P and the MA12070/P feature several protection modes such as under-voltage lockout (UVLO), short-circuit/overcurrent and DC protection, and over-temperature warning and error. The MERUS integrated multilevel class D audio amplifier ICs come in a 64-pin thermally enhanced QFN package with exposed thermal pad (EPAD).

Block diagram for multi-chip amplifier module without filters (Click on image to enlarge)


The family of fully integrated audio amplifier ICs from the MERUS class D audio portfolio consists of the analog audio input versions, MA12040 and WiSA™ Endorsed MA12070, and the I2S digital audio input versions, the MA12040P and the MA12070P. All four devices are now available.