Class D Car Audio Amplifier Board with Advanced Diagnostics

The amplifier can also be combined with the SPC582B Chorus automotive-grade microcontroller to provide an electric vehicle audible warning (or audible vehicle alarm system, AVAS) solution.
The FDA903D amplifier is available in a PowerSSO-36 slug-down package and features configurable power limiting, high-speed I²C and legacy mode interfaces, and an internal finite state machine.
The initial state of the device is standby and it cannot exit this state until the I2C interface is properly enabled: this means providing the correct supply voltage, I2S clock, I2S data and a valid enable pin combination (in order to determine the I2C device address) .
The system is needed in new vehicles to alert pedestrians to the presence of electric vehicles because they emit very little noise. The warning sound can be a driver-triggered sound (like a horn) or automatically mimic the sound of an engine running. According to government regulations, from 2021, vehicles must have a minimum continuous noise level of 56 dBA (within 2 meters) and a maximum of 75 dBA if the car is traveling at 20 km/h (12 mph) or slower.
Each enable pin combination represents an address. Up to 8 devices can be used in the same application over one I2C bus. The internal I2C registers are preset to "default conditions", waiting for the next instruction from I2C. Return from standby (i.e., all enable pins are 0) will cause the amplifier to reset. By definition in a finite state machine, the same events will occur if the PLL is not locked, I2S is missing or incorrect, Vcc is removed for system reset. FDA903D only works in I2C slave mode.
The combination of the AEK-AUD-D903V1 ​​with the AEK-MCU-C1MLIT1 (hosted SPC582B Chorus automotive-grade microcontroller) provides a viable low-cost solution for entry-level AVAS systems.