Overview

Features and Benefits

A2B BUS FEATURES
  • Line topology
    • Single master, multiple slave
    • Up to 15 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
A2B TRANSCEIVER FEATURES
  • 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

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 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.

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.

Table 1. Product Comparison Guide
Feature AD2426W AD2427W AD2428W
Master capable No No Yes
Functional TRX blocks A only A + B A + B
I2S/TDM support No No Yes
PDM microphone inputs 4 mics 4 mics 4 mics
Max node to node cable length 15 m 15 m 15 m

Applications

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

Please contact your local ADI sales office or authorized ADI product distributor to receive additional product information.

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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