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AMC3336-Q1: HGND connected to AGND

Michael Koch
Prodigy 80 points
Part Number: AMC3336-Q1
Other Parts Discussed in Thread: AMC3336

Tool/software:

Hello

I am considering using the AMC3336 in conjunction with a Hall sensor (Melexis).

This has an output voltage of max. 5V. I would use a voltage divider to limit the voltage at the AMC3336 to 1V.

As the sensor itself requires more than 10mA supply, it is not supplied by the AMC3336 itself but by an external 5V. I would therefore have to combine the two GNDs from the external source with that of the AMC3336 (HGND). Would there be a problem here?


Alternatively, would it be better not to supply the HGND directly with the GND of the external source but via a resistor?

Anything else I may not have seen?

  • 0
    TI__Guru 55062 points

    Hi Michael,

    What current magnitude and voltage level do you plan to sense to? 

    I'm curious why you would choose this configuration as opposed to sensing the current using a shunt resistor. 

    Either way would be fine. Do you plan to test EMC for this product? 

    If so, you may want to consider the addition of ferrite beads as per this application note: https://www.ti.com/lit/an/sbaa515a/sbaa515a.pdf

  • 0 in reply to Alexander Smith
    Prodigy 80 points

    Hi Alexander

    I have to measure up to 700A at 600V DC link voltage.
    I already use the AMC3336 for DC and AC voltage measurement and wanted to keep the parts the same.

    Yes EMC tests are planned. Thanks for the application note

  • 0 in reply to Michael Koch
    Prodigy 80 points

    The sensor is only 20mm (not cm) away from the AMC3306.
    So don't think i need ferrites or a CM Choke

  • 0 in reply to Michael Koch
    TI__Guru 55062 points

    Hi Michael,

    I see. I did measure up to 920Apk with a 50uohm, 50W shunt last week. It is possible and offers some benefits for simplifying calibration requirements. 

    I have <3% accuracy without calibration, I should be well within 1% without active temperature compensation once I apply a gain calibration with post processing. If you are interested in my results or any details, please let me know. I'll have something to share in the coming weeks. 

    Otherwise, good luck! Please keep me posted if you need any help.