Datasheet AD2421W, AD2422W, AD2425W (Analog Devices)

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Automotive Audio Bus A2B Transceiver Data Sheet AD2421W/ AD2422W/ AD2425W A2B BUS FEATURES GENERAL DESCRIPTION Line topology
The Automotive Audio Bus (A2B®) provides a multichannel,
Single master, multiple slave
I2S/TDM link over distances of up to 15 m between nodes. It
Up to 15 m between nodes and up to 40 m overall cable
embeds bidirectional synchronous data (for example digital
length
audio), clock, and synchronization signals onto a single differ-
Communication over distance
ential wire pair. A2B supports a direct point to point connection
Synchronous data
and allows multiple, daisy-chained nodes at different locations
Multichannel I2S/TDM to I2S/TDM
to contribute or consume time division multiplexed channel content. A2B is a single-master, multiple-slave system where the
Clock synchronous, phase aligned in all nodes
transceiver chip at the host controller is the master. The master
Low latency slave to slave communication
generates clock, synchronization, and framing for all slave nodes.
Control and status information I2C to I2C
The master A2B chip is programmable over a control bus (I2C)
GPIO over distance
for configuration and read back. An extension of this control
Phantom power or local power slave nodes
bus is embedded in the A2B data stream, which grants direct
Configurable with SigmaStudio graphical software tool
access of registers and status information on slave transceivers
Qualified for automotive applications
as well as I2C to I2C communication over distance.
ADDITIONAL TRANSCEIVER FEATURES Table 1. Product Comparison Guide Configurable as A2B bus master or slave (AD2425W) I2C interface Feature AD2421W AD2422W AD2425W 8-bit to 32-bit multichannel I2S/TDM interface
Master capable No No Yes
I2S/TDM/PDM programmable data rate
Functional TRX blocks A only A + B A + B
Up to 32 upstream and 32 downstream channels
I2S/TDM support No No Yes
PDM inputs for 4 high dynamic range microphones
PDM microphone inputs 4 mics 4 mics 4 mics
APPLICATIONS
Maximum node to node 15 m 15 m 15 m
Automotive audio communication link
cable length
Active noise cancellation Microphone arrays for hands free and in car communication FUNCTIONAL BLOCK DIAGRAM IOVDD DVDD PLLVDD VOUT1 VIN VOUT2 ATRXVDD/BTRXVDD SCL A2B BP SDA PLL VREG1 VREG2 TRX B BCM IRQ/IO0 I2C (Towards Last Slave) BN ADR1/IO1/CLKOUT1 SWP ADR2/IO2/CLKOUT2
®
DIAGNOSTICS SENSE BCLK AP SYNC A2B I2S/TDM TRX A ACM DTX0/DTX1 PDM (Towards AN Master) DRX0/DRX1 IO7 VSS VSSN
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