“A2B” simplifies communications and reduces costs

In this article, we will introduce the transceiver "A2B" released by Analog Devices.

AB is an abbreviation for "Automotive Audio Bus" and, as the name suggests, is a technology developed to reduce the weight (fuel economy) and cost of audio harnesses for in-vehicle infotainment, which is becoming increasingly electrified. It has been adopted by many automakers, including Ford Motor Company, in their mass-produced cars and is currently the standard communication bus in the car audio industry. Furthermore, the technology is also being adopted in non-automotive devices (industrial, consumer, etc.).

This time, we will introduce the three major features of "A2B" and the benefits that can be expected in electronic and industrial equipment.

1. 50Mbps communication, low latency of 50μsec for I2S/I2C/SPI signal transmission

2. Achieve data communication up to 300m using inexpensive UTP cable

3. Simple design system

Click here for a demo video that gives an image of the actual operation

1. 50Mbps communication, low latency of 50μsec transmission of I2S/I2C/SPI signals

The major features of AB are that it enables communication at a data rate of 50 Mbps using inexpensive UTP cable, and because it does not require a software stack on the sub-side, there is only a 50 μsec delay between nodes even in a daisy chain connection.

Among the various existing communication standards, IS/I2C/SPI are positioned as shown in the diagram below, but using AB expands the usability of IS/I2C/SPI and also plays a complementary role to Ethernet.

2. Achieve data communication up to 300m using inexpensive UTP cable

The only cable required for communication is a pair of UTP (unshielded twisted pair). Since no special cables are required, this reduces the amount of wiring between boards and can lead to a simpler and less costly system.

 

The communication distance between nodes is up to 30m, and by connecting nodes together, communication is possible up to 300m for the system. Devices are divided into main and sub, and the maximum number of connections is 16 channels.

 

3. Simple design system

AB extends IS, IC, and SPI communications while maximizing design simplification by eliminating the need for a software stack or storage memory at each node and removing the processing burden from connected processors.

The physical layer is the noise-resistant LVDS (low amplitude differential signaling), and in addition to signals it can also supply clocks and up to 50W of DC voltage, making it possible to supply bus power to sensors, microphones, speakers, etc.

Device configuration can also be visually guided through the design process using the graphical software tools SigmaStudio ^® and SigmaStudio+®.

If you have any questions about A2B cable/connector selection or design, please feel free to contact us.

Boards for performance and EMC evaluation are also available.

Analog Devices offers multiple evaluation boards for speedy performance evaluation.

There are eight basic types of A2B evaluation boards:

*AD2428 has 4 types on the top row, AD2437 has 4 types on the bottom row

We also offer boards that have had the A2B connector replaced with one made by Rosenberger and are specialized for EMC verification, so please feel free to contact us using the inquiry button at the bottom of the page.

AD2428 Evaluation Board Comparison Table

Order number	EVAL-AD2428W D 1BZ	EVAL-AD2428W B 1BZ	EVAL-AD2428W C 1BZ	EVAL-AD2428W G 1BZ
Main/Sub	Main/Sub	Sub Only	Sub Only	Sub Only
power supply	Locally powered	Bus Powered	Bus Powered	Locally powered
Audio in/out	3.5mm mini jack and Optical-SPDIF	3.5mm mini jack	-none-	3.5mm mini jack
PDM mic	3 -ch	2-ch	4-ch	-none-
Photo-image

AD2437 Evaluation Board Comparison Table

Order Number	EVAL-AD2437A1MZ	EVAL-AD2437A1NZ	EVAL-AD2437B1MZ	EVAL-AD2437B1NZ
Main/Sub	Main/Sub	Main/Sub	Sub Only	Sub Only
power supply	Locally powered	Locally powered	Bus Powered	Bus Powered
connector	RJ-45	XLR	RJ-45	XLR
Photo-image

Model A/B = Main/Sub
Model M/N = RJ-45/XLR

A comparison of the actual size of the AD2428 evaluation board is as follows:

Key features of A2B

Line topology
- Single main, multiple sub
- Cable length is up to 15m between nodes, up to 80m for the entire system (AD2437 has a maximum of 30m between nodes, and a maximum of 300m for the entire cable)

-Maximum number of nodes is 17 (1 main, 16 sub)

·data communication
- Audio data: I2S/TDM/PDM
- Multi-channel audio transmission (up to 32ch Upstream + 32ch Downstream)
- Clock synchronization (phase is synchronized at all nodes)
- Low latency communication (50μs)
- Control data: I2C/SPI
- Long Distance GPIO
- Bus power transmission: Max. 50W

- Robust EMC performance
Easy setup with SigmaStudio® and SigmaStudio+® graphical software tools

Application example

・Meeting system

・Call center

・Large equipment

Click here for recommended articles/materials

• A2B® technical information database

Click here to purchase products

• AD2428KCPZ
• EVAL-AD2428WD1BZ
• EVAL-AD2428WB1BZ
• EVAL-AD2428WC1BZ
• EVAL-AD2428WG1BZ
• AD2437BCPZY
• EVAL-AD2437A1MZ
• EVAL-AD2437A1NZ
• EVAL-AD2437B1MZ
• EVAL-AD2437B1NZ

Click here for manufacturer site/other related links

• AD2428 product information (Various data sheets can be downloaded from here)
• AD2427 product information (Various data sheets can be downloaded from here)
• AD2426 Product Information (All data sheets can be downloaded here)
• AD2437 Product Information (Various data sheets can be downloaded here)

Inquiry / Quotation

If you have any questions about the products introduced in this article, or if you would like more information, please feel free to contact us using the form below.

Also, related to this article, we held a seminar in the past titled "What are A2B technologies that can reduce costs at the system level, such as noise cancellation?" If you would like to request materials for the seminar held, please contact us with the following in your inquiry: "What is A2B technology that can reduce costs at the system level, such as noise cancellation? I would like materials for the seminar."