Class-D audio power amplifiers emit at up to 10W for eCall and telematics
Two single channel fully differential 10W Class-D audio power amplifiers, the FDA803S and FDA903S, are the latest members of STMicroelectronics’ FDA (fully digital amplifier) family. They 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, said ST. Feedback within the chip, before the external L-C output filter, simplifies the circuit design and saves space.
The amplifiers have I2C configurability and in-play diagnostics that include clipping detection, thermal warning, overcurrent protection and open-load detection. The level of integration minimises external components and bill-of-materials costs.
They also exhibit low quiescent current which contributes to vehicle energy efficiency, said ST.
Both the FDA803S and FDA903S feature an I2S digital input and a time division multiplexing (TDM) interface. They can be configured for various sampling frequencies between 8.0 up to 96kHz to optimise performance with a variety of audio sources. The lower sampling frequencies, from 8.0 to 32kHz, enable designers to save memory space in applications such as warning tone generators, said ST.
The FDA903S additionally integrates a real-time, load-current monitor, allowing self-diagnostic capability compatible with the demands of functional safety applications up to ASIL A level.
Both devices are supplied in a QFN32 5.0 x 5.0mm exposed pad-down package which does not required a heatsink. The low component count and the elimination of a heatsink is also claimed to minimise the bulkiness of power amplifiers built using these ICs.
There is also an evaluation board, the EVAL-FDA903S.
Both the FDA803S and FDA903S are in production now.
