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December 2022

AD2430/AD2438

©2022 Analog Devices, Inc. All rights reserved. Trademarks and

registered trademarks are the property of their respective owners.

 I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).

GENERAL DESCRIPTION

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 synchroni-

zation signals onto a single unshielded twisted pair (UTP) dif-

ferential 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, multiple-subordinate node system where

the transceiver at the host controller is the main transceiver. The

main node generates clock, synchronization, and framing for all

subordinate nodes. The main A2B transceiver chip is program-

mable 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 to registers and status infor-

mation on subordinate node transceivers, as well as I2C to I2C

communication from the host to a peripheral in a subordinate

node.

The transceiver can connect directly to general-purpose digital

signal processors (DSPs) or microprocessors, field-programma-

ble gate arrays (FPGAs), application-specific integrated circuits

(ASICs), microphones, analog-to-digital converters (ADCs),

digital-to-analog converters (DACs), and codecs through a mul-

tichannel I2S/TDM interface. It also provides a pulse density

modulation (PDM) interface for direct connection of up to four

PDM digital microphones. The transceiver’s pulse width modu-

lated (PWM) outputs can control LED drivers or voltage

regulators. GPIO status and control is directly conveyed

between nodes.

Additionally, 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.

Table 1. Product Comparison Guide

Feature

AD2430

AD2438

Main capable/subordinate capable

Yes/Yes

1

Yes/No

Maximum number subordinate nodes2 2

Specification defined by the most restrictive device data

sheet in systems with AD2421, AD2422, AD2425, AD2426,

AD2427, AD2428, AD2430, AD2431, AD2432, AD2433, or

AD2435

Functional TRX blocks

1

1

Maximum number audio channels

Up to 7 slots

Up to 64 slots with maximum of 32 slots in one direction

I2S/TDM support

Yes

Yes

PDM microphone inputs

4 mics

4 mics

PWM support

Yes

Yes

Available A

2B bus power

Up to 700 mW

Up to 700 mW

Maximum node to node cable length

Up to 15 m

Up to 15 m

Package

32-lead LFCSP

32-lead LFCSP

1 Last subordinate node only.

2 Interoperable with AD242x and AD243x products. Refer to the respective product data sheet for further details. Specification defined by the most restrictive device data sheet

in systems with AD2421, AD2422, AD2425, AD2426, AD2427, AD2428, AD2430, AD2431, AD2432, AD2433, or AD2435.