Analog Device's AD1871 24 bit analog to digital converter

Hello,

Is anyone using Analog Device's AD1871 in their design? I'm trying to use two of them in cascade mode and I'm finding bugs in the part, and plenty of mistakes and deficiencies in the data sheet. The control part and the audio data are both in cascade mode.

If anyone is using the part and specifically in cascade mode, could you please tell me what you've seen and have you been able to get the part to work correctly?

I've had a few discussions with the manufacturers and I'm not convinced they've ever tested this part with the control port and the data port both in cascade mode.

I'm very disappointed in the part and the documentation and I'm close to designing out of the product.

Any help, advice or just share the problems you've had with the part would be very helpful.

Thanks, Dale

Reply to
dale.prather
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Not that particular part, but in general for most recent-generation serial-data-bus AD parts you really really have to make sure that you're obeying the clock rise, fall, hold, and skew times.

A quick look at the AD1871 datasheet makes me see that they don't specify rise/fall times. That makes it hard to obey them to the letter! Wjhen daisy chaining things must get exponentially worse.

In my limited experience with their serial-control-bus DDS's, a typical PIC or microcontroller resulted in flaky operation because the rise/fall times of the serial bus clock being in the 3-4ns region was way too long.

Tim.

Reply to
Tim Shoppa

Thanks for the reply Tim. I finally found the problem. The data sheet has yet another mistake in it! The data sheet is worthless. Bit_Clk high to low, not low to high clocks in the LRClk.

Dale

Reply to
dale.prather

The analog design guys tend to do truly bizarre digital interfaces, then explain them badly and often just plain wrong. Timing diagrams can be especially bad. They also don't like to distinguish between edges and levels. "When LE goes high, data is transferred..." could mean either, and usually does.

John

Reply to
John Larkin

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