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AMC1303M2510: SDFM data from the AMC1303 IC was not correct.

Karthick Kumar T K
Prodigy 100 points
Part Number: AMC1303M2510

Tool/software:

We're using AMC1303M2510 in our converter for DC current sense. We designed the circuit for operating range of 100Amps DC. While checking for SDFM data, I'm getting some variations in digital data.

1. When I was testing, i had  directly connected the external wire and passing DC current by soldering directly on the SMD pad of resistors the data was coming quiet good.

2. When I was applying the same DC current but on directly on top of SMD resistors. And  without running the converter the data was not coming right.

Here, in both cases the DC current is passing through the sense resistor of1.5mOhm 3 in parallel. By calculation the equivalent resistance has to come 0.5mOhms. But, by the data what we're getting the resistance seems like 0.7mOhms, we're assuming like because of the ENIG coating and the solder material quality the resistance might increased. So, can you please figure out what's can be the reason why we're getting increased value in SDFM and whether our assumptions are right or not. Help me resolve this issue. Thank you.

  • +1
    TI__Expert 6030 points

    Hi Karthick,

    The difference in measurement you are seeing is probably due to the soldering.  We have seen differences in the shunt resistance value due to its soldering before.  You can move to a single shunt solution to get a lower offset in the shunt resistance, or you can do a gain calibration to account for the resistance change.

    Thanks.