The FDA803S and FDA903S have been added to STMicroelectronics’ FDA (fully digital amplifier) family. The fully differential 10W Class-D audio power amplifiers are designed for automotive applications like eCall, telematics, and wherever an audio channel needs to reproduce human voice, music, or warning messages at a standard output power level of up to 10W.

The amplifiers integrate an I2S front end, digital core, 24-bit DAC with 100dB resolution, and class-D PWM output stage. The integrated digital audio processing ensures high sound quality within a compact circuit footprint, says ST. To simplify circuit design and save space, feedback occurs within the chip, before the external L-C output filter.

Both power amplifiers are I2C-configurable and have in-play diagnostics including clipping detection, thermal warning, over-current protection, and open-load detection to minimise the number of external components and reduce bill of materials costs. The FDA903S also integrates a real-time load-current monitor, allowing self-diagnostics compatible with the demands of functional-safety applications up to ASIL A.  

Both devices come in QFN32 5.0 x 5.0mm exposed pad-down packages for designs which do not require a heatsink, which together with the low component count minimises bulk in the end design, says the company. They also have low quiescent current, contributing to minimising size, weight, and power consumption to improve overall vehicle energy efficiency.

Both power amplifiers have an I2S digital input and a time-division multiplexing (TDM) interface. They can be configured for sampling between 8.0 to 96kHz. The lower sampling frequencies – up to 32kHz - enable designers to save memory space in applications such as warning tone generators.

The company also offers the EVAL-FDA903S evaluation board.

Both power amplifiers are in production now.