Infineon Technologies is uniting its existing portfolio of multi-chip modules and discrete audio products under one brand, MERUS.

The new brand is intended to spearhead the company's belief that the best audio amplifier ICs produce sound in the speakers, not heat to the surroundings; should be heard, but not seen; will be smaller and lighter, not bulky and heavy and must be both robust and flexible.

Based on these principles, Infineon is introducing a family of highly power efficient monolithic class D audio amplifier solutions that it intends to drive improvements in terms of audio performance.

The key building block that will be supporting this new brand of products is a new technology: the multilevel switching technology for class D audio amplifiers, which will affect the amplifier evaluation parameters such as power consumption, solution size, audio performance, electromagnetic interference, and BOM cost.

As a result, up to five levels of output signal modulation are now feasible, according to Infineon. Compared to their traditional counterparts, multilevel amplifiers use additional on-chip MOSFETs and capacitors to produce outputs with higher signal granularity, i.e. higher switching frequencies and scalable output signal levels. This results in a small form factor and virtually no switching loss measurable in idle mode.

Infineon is introducing a family of four integrated multilevel audio amplifiers, the MA12040/P and the MA12070/P in two versions, respectively. They have power consumption in the 250mW range and are suited for portable battery powered products and applications with challenging thermal conditions meeting the critical design objectives for modern audio applications.

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 situations they consume significantly more input power (~1 W on average) than the first generation of MERUS integrated multilevel audio amplifier ICs (~0.25 W).

The newly introduced devices 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 160 W peak (16 A max) in a single PBTL channel or, for instance, it can be set up as a 2.1 system with 2 x 20 W tweeters as SE channels and 1 x 40 W 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, reducing the bill of material 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 undervoltage 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).

By: DocMemory
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