Cable and connections for A2B

Revised 27-Apr-20. The EE-404 app note is no longer available, but the same information is now available in a different document. This note was updated to reflect that, as well as Clockworks offers standard cables. ADI's document ‘A 2 B® System Specification Rev 1.2 ’ ( https://www.analog.com/media/en/secure/a2b/A2B-System-Specification-Rev1.2.pdf ) describes the cable characteristics as well as some connectors that have been used for A 2 B ® in automotive applications. However it does not provide cable part numbers, and if you dig deeper the recommended cables are automotive ones and not available for purchase by mere mortals. Clockworks has used Belden 1353A and it seems to work fine in this application. ADI's document calls for +/- 10% impedance variation (100 ohm nominal) and this cable is +/-15%. 100 MHz. Insertion loss for the cable at 100 MHz is specified at 0.26 dB/m versus 0.3 dB/m in ADI's document, and cable return loss at 100 MHz of 20 dB compares well with the 18 dB (and similar at other frequencies). While it wasn't stated in the original ADI documents, there are now references to CAT5 UTP compliant cable as being the type of cable to use, and the Belden 1353A is compliant. Clockworks A 2 B module uses the same Molex DuraClik connector system that is used on the Analog Devices EVM boards. As is typical with this type of crimped pin connector, the special tool to make crimps is not cheap. However standard microterminal crimpers can be used for the wire crimp - but use a high quality ones. We like the Engineer brand from Japan, the PA-09 being the best for this particular application. Crimping the strain relief is little more problematic for a generic hand tool. The Molex pin should have tabs wrap the cable insulation, not pierce it. A conventional crimp tool might do the latter. If you don't overcrimp it with the standard tool it will be fine. Clockworks uses a jewelry crimper for the second (insulation) crimp to avoid piercing the insulation when making cables by hand. However for correctness the actual Molex crimper would be the best tool for any sort of critical application (though the Duraclik might not be appropriate in that case). Clockworks also offers standard cables for sale, these are mode by a cable house with experience in a range of cable assembly procedures.

Using the EVM board as a SigmaDSP ADAU1761 development platform with SigmaStudio

The EVM board uses an ADAU1761 for the analog I/O as this maintains compatibility with the Analog Device's A 2 B EVM boards. If not using theClockworks EVM board can be used as a SigmaDSP development platform, and the A 2 B module header on the Clockworks EVM provides easy access to the I 2 S lines if needed to interface with your own hardware. The EVM has a 10 pin .1" header for attaching the USBi pod to the board. With the A 2 B module removed the ADAU1761 will need to be supplied with its master clock (12.288 MHz is what is normally used). There are two ways to do that: Populate the DNP locations for the oscillator, series resistor, and decoupling cap. The advantage of this is the parts are now part of the board. The disadvantage is if you want to use the board for A 2 B development again you will need to remove the parts. Add an oscillator that plugs in to the auxiliary connector for power and one pin in to the module socket. The advantage of this is its's trivial to return the board for use with an A 2 B module. The disadvantage is it's a bit hacky. There are more details in the Clockworks manual, but here's two pictures that give you a better idea of the two choices. PCB location for adding oscillator for using board without A 2 B Oscillator with wires attached plugged in to the EVM

Using the A2B module + EVM with ADI's Sigma Studio tools

The Clockworks' A 2 B® module and EVM operates the same as Analog Devices' WBZ evaluation board. Any of the provided ADI examples can be used with the module+EVM setup. Just remember to select the AD2428 chip type from the drop down selection box in Sigma Studio®.

A2B applications development - Documents - Clockworks Signal Processing Library

A2B applications development

This section of the local Clockworks PartnerZone wiki provides some quick summary information about how the EVM and/or the A²B module can be used to reduce development time and cost for A²B systems.

Full details of the EVM and A²B module are in the Clockwork's user guide. The EVM board comes with the full set of design files and has been designed with hacking it for use in prototypes or small systems in mind.