ADI AD2428WCCSZ

The Automotive Audio Bus (A²B) provides a multichannel, I2S/TDM link over distances of up to 15 m between nodes. It embeds bidirectional synchronous pulse-code modulation (PCM) data (for example, digital audio), clock, and synchronization signals onto a single differential wire pair. A²B supports a direct point to point connection and allows multiple, daisychained nodes at different locations to contribute and/or consume time division multiplexed channel content.

A²B is a single-master, multiple-slave system where the transceiver chip at the host controller is the master. The master generates clock, synchronization, and framing for all slave nodes. The master A²B chip is programmable over a control bus (I²C) for configuration and read back. An extension of this control bus is embedded in the A²B data stream, which grants direct access of registers and status information on slave transceivers as well as I²C to I²C communication over distance.

The transceiver can connect directly to general-purpose digital signal processors (DSPs), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), microphones, analog-to-digital converters (ADCs), digital-toanalog converters (DACs), and codecs through a multichannel I²S/TDM interface. It also provides a PDM interface for direct connection of up to four PDM digital microphones.

Finally, the transceiver also supports an A²B bus powering feature, where the master node supplies voltage and current to the slave nodes over the same daisy-chained, twisted pair wire cable as used for the communication link.

• Line topology Single master, multiple slave Up to 75 m between nodes and up to 40 m overall cable length
• Communication over distance Synchronous data Multichannel I2S/TDM to I2S/TDM Clock synchronous, phase aligned in all nodes Low latency slave to slave communication Control and status information I2C to I2C GPIO over distance
• Bus power or local power slave nodes
• Configurable with SigmaStudio graphical software tool
• Qualified for automotive applications
• Configurable as A²B bus master or slave (AD2428W)
• I2C interface
• 8-bit to 32-bit multichannel I2S/TDM interface I2S/TDM/PDM programmable data rate Up to 32 upstream and 32 downstream channels
• PDM inputs for 4 high dynamic range microphones on masters or slaves
• Support for receiving I2S data on nodes with up to 4 PDM microphones
• Unique ID register for each transceiver
• Support for crossover or straight-through cabling
• Programmable settings to optimize EMC performance

• Automotive audio communication link
• Active noise cancellation
• Microphone arrays for hands free and in car communication