Features and Benefits


  • Line topology
    • Single main node, up to 16 subordinate nodes
    • Up to 15 m between nodes and up to 80 m overall cable length
  • Communication over distance
    • Synchronous data
      • Multichannel I2S/TDM to I2S/TDM
      • Clock synchronous, phase aligned in all nodes
      • Low latency subordinate node to node communication
    • Control and status information I2C to I2C
    • GPIO over distance
  • Bus power or local power subordinate nodes
  • Configurable with SigmaStudio graphical software tool
  • AEC-Q100 qualified for automotive applications


  • Configurable as A2B bus main node or subordinate node
  • Programmable via I2C and SPI interfaces
  • 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 main or subordinate nodes
  • Simultaneous reception of I2S data 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


  • Mixed Signal
    • Up to 50 W A2B bus power
    • Increased voltage regulator capacity (up to 100 mA)
    • ADC monitoring of supply voltages
    • Supports 3.3 V input at VIN in Low Voltage Input (LVI) mode
  • Digital
    • High speed SPI (up to 10 Mbps) over distance
    • A2B bus self-discovery
    • Dedicated hardware reset pin
    • I2S/TDM crossbar switch
      • Flexible mapping of Tx/Rx TDM channel data to A2B slot
    • Support for I2C fast mode plus (1 MHz)
    • Support for in cabin LED control using 4 PWM outputs
    • 8 GPIO pins with configurable pin mapping

Product Details

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 unshielded twisted pair (UTP) differential cable. A2B supports a direct point to point connection and allows multiple, daisy-chained nodes at different locations to contribute and/or consume time division multiplexed channel content.

A2B is a single main node, multiple subordinate node system where the transceiver at the host controller is the main node. The main node generates clock, synchronization, and framing for all subordinate nodes. The main A2B transceiver is programmable over a control port (I2C/SPI) for configuration and read back. An extension of the control port protocol is embedded in the A2B data stream. This allows direct access to registers and status information on subordinate transceivers, as well as I2C to I2C, SPI to I2C, or SPI to SPI communication from the host to a peripheral in a subordinate node. SPI to SPI communication between subordinate nodes can be performed directly and does not need to involve the main node.

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-to-analog converters (DACs), and codecs through a multichannel I2S/TDM interface. It also provides a pulse density modulation (PDM) interface for direct connection of up to four PDM digital microphones.

Finally, the transceiver also supports an A2B bus powering feature, where the main node supplies voltage and current to the subordinate nodes over the same daisy-chained, twisted pair wire cable as used for the communication link. Complete technical specifications are available for the A2B transceiver. Contact your nearest Analog Devices sales office to complete the nondisclosure agreement (NDA) required to receive additional product information.


  • Distributed audio systems
  • Personal audio zones
  • In car communications
  • Smart/remote tuner modules
Contact your nearest Analog Devices sales office to complete the nondisclosure agreement (NDA) required to receive additional product information.

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