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ADUM3402 and ADM3078 versus ADM2682

Question asked by NTipping on Oct 23, 2013
Latest reply on Nov 11, 2013 by NTipping

I have an existing RS485 half duplex design using the ADUM3402, the ADM3078 running at 3.3V and a DC-DC convertor. I'm looking to save some space (as always) and am considering using the ADM2682. However, I've been trying to interpret the supply current specifications, and however I look at it, the single device solution apprears to require about twice the current under the same conditions (60R load). There doesn't appear to be a spec. for the power conversion efficiency, so am I misinterpreting the specs? I need a low-power solution.

 

On the subject of the ADM3078, are there any known issues with the fail-safe detection features? I appear to get false start characters from the receiver on a low-capacitance bus (<600pF approx, 2 x 120R terminators) when the the transmitter turns off, with a baud rate of 240k. Once the bus capacitance rises above about 600pF, the voltage collapse appears to be slow enough for this not to happen.

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