STMicroelectronics Announces Flexible, Space-Saving Class-D Amplifier for Car Audio

September 23 2024, 00:25
STMicroelectronics' latest HFA80A automotive-grade analog-input class-D audio amplifier combines high efficiency, small size, and a low bill of materials, with load diagnostics optimized for automotive and native electromagnetic compatibility (EMC). With its feedback-before-filter topology and 2MHz nominal PWM frequency, the ST HFA80A lets designers optimize the output filter for the targeted performance and achieve a compact outline with small component values. 
 

According to STMicroelectronics, the new HFA80A amplifier delivers clear and powerful listening experiences, driving up to 4x 49W into 2Ω speakers at 14.4V and with typical harmonic distortion (THD) specified at 0.015% (1W/4Ω). The new amplifier is specified for low output noise and crosstalk, with 80dB power supply rejection specified at 1W/1kHz with 4Ω loads.

Flat frequency response up to 40kHz ensures generous bandwidth for high-resolution audio, which designers can extend to 80kHz by optimizing the filter. In addition, the HFA80A can handle performance-centric applications such as noise cancelling thanks to low latency by design.

The automotive-specific diagnostics is based on a specially conceived noise-immune algorithm capable of detecting anomalous load conditions and variations. Features include independent DC and AC load detection for each channel, detection of short-circuit on startup, and overcurrent protection with configurable thresholds. Further diagnostic checks include input-voltage DC-offset detection, output-current offset detection, and thermal protection with a choice of four different thermal warnings. Spread-spectrum operation simplifies meeting the mandatory CISPR 25 specification, with no additional EMC-specific filtering required.

A dedicated, configurable pin signals the host microcontroller when new diagnostic information is available, which simplifies host communications and relieves CPU workload. An I2C-bus interface provides access to the device features and diagnostic data, and a backup mode lets the amplifier continue operating even if I2C control is lost. In addition, the HFA80A features a digital admittance meter (DAM) that eases development by helping engineers check the connected speaker characteristics without external measurement tools or sensors.

The HFA80A is available in a compact 7mm x 7mm LQFP48L thermally enhanced package with exposed pads, from $4.80 for orders of 1000 pieces.
www.st.com
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