STMicroelectronics introduces automotive amplifier

Featuring a feedback-before-filter topology and a 2MHz nominal PWM frequency, the HFA80A allows designers to fine-tune the output filter for optimal performance while maintaining a compact design with small component values. Its spread-spectrum operation aids in meeting the CISPR 25 specification without the need for additional EMC-specific filtering.

This amplifier ensures a clear and robust audio experience, capable of driving up to 4x 49W into 2Ω speakers at 14.4V, with a typical harmonic distortion (THD) of just 0.015% at 1W/4Ω. It guarantees pure sound, featuring low output noise, minimal crosstalk, and 80dB power supply rejection at 1W/1kHz with 4Ω loads.

With a flat frequency response up to 40kHz, the HFA80A offers ample bandwidth for high-resolution audio, and designers can extend this to 80kHz by optimising the filter. Its low-latency design also makes it suitable for performance-driven applications such as noise cancellation.

The HFA80A includes automotive-specific diagnostics that use a noise-immune algorithm to detect load anomalies and variations. Key features include independent DC and AC load detection for each channel, short-circuit detection during startup, and overcurrent protection with configurable thresholds. Additional diagnostics include input-voltage DC-offset detection, output-current offset detection, and thermal protection with four different levels of thermal warnings.

A dedicated, configurable pin signals the host microcontroller when new diagnostic data is available, simplifying communication and reducing CPU workload. An I2C-bus interface provides access to the device’s features and diagnostic information, with a backup mode ensuring continued operation even if I2C control is lost. Additionally, the HFA80A includes a digital admittance meter (DAM) to assist engineers in checking speaker characteristics without the need for external measurement tools or sensors.