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AMC1210: Flip of sign

Genius 3980 points

Part Number: AMC1210

Hi,

We have the following system:

AMC1204 isolated Delta-Sigma Modulator generates data stream to AMC1210. CLKx is produced by the AMC1210. If we sweep through the whole range of the AMC1204 (-320mV...+320mV) the AMC1204 produces a datastream from permanent low over 50% low/high to permanent high. So far so good.
We now have the problem that some of the AMC1210 switches the sign of read-out value when we go close to the low limit of the AMC1204 (-320mV). In this case the AMC1204 produces a permanent low signal.

Questions:
1. Is it safe to operate the AMC1204 input voltage between -320mV and -500mV (+320mV to +500mV respective)? Does the AMC1204 still produces a permanent low (permanent high respective) signal? (clipping still working)

2. Is there any problem known when the AMC1210 has a permanent low input signal?

Thanks and best regards,

Patrick 

  • Hi Patrick,

    Thanks for your post!

    1) Please refer to table 6.1 for the absolute maximum ratings and section 7.3.3 Digital output. -500mV on the input is stressing the device to the absolute maximum ratings which may lead to issues. Yes the device will output only 1's or 0's depending on a high or low input past +/-320mV.

    " Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
    only, and functional operation of the device at these or any other conditions beyond those indicated under the Electrical Characteristics
    is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability."

    2) No issue as long at the absolute maximum rating of GND -0.3V is not violated.

    Best regards,

    Alex Smith
    Applications Engineer | Precision Delta-Sigma Converters

    Check out our helpful resources:
    TI Precision Data Converters | TI Precision Labs - ADCs | Analog Engineer's Calculator Data Converters Learning Center | Selection Guide

  • Genius 3980 points

    In reply to Alexander Smith:

    Alex,

    Thank you for your answer. Meanwhile we could identify the problem in a wrong offset calculation on our side.

    As we are doing a redesign of the board we plan to replace the AMC1204DW with a AMC1306M25DWV. Is this a suitable 1:1 replacement (apart from the footprint)?
    Any change neeeded on the AMC1210 side or is this a 1:1 replacement?
    We also plan to change the High-side supply to change from 5V to 3.3V. Any drawback in doing this?

    Best regards,

    Patrick

  • In reply to Pruf:

    Hi Patrick,

    Glad to hear that the issue was resolved! 

    This is a suitable 1:1 replacement apart from the footprint like you mentioned. 

    No issues with the AMC1210 or the power supply. 

    Best regards,

    Alex Smith
    Applications Engineer | Precision Delta-Sigma Converters

    Check out our helpful resources:
    TI Precision Data Converters | TI Precision Labs - ADCs | Analog Engineer's Calculator Data Converters Learning Center | Selection Guide

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