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DRV5011: Measurement

Ray Vincent Aranzaso
Genius 14525 points
Part Number: DRV5011

Hi,

Good Day.

The customer needs to know the correct way to measure the output (between GND and output) resistance of DRV5011. He uses Fluke and Keithley and gets different results with each meter.

Best Regards,

Ray Vincent

  • 0
    TI__Mastermind 22745 points

    Hey Ray,

    I expect the accuracy tolerance of both instruments may not be identical, also he may not be probing from the same spot.  These alone would cause some discrepancy.  Can you quantify how different the results are and provide a diagram of how your customer is taking measurements?

  • 0 in reply to Patrick Simmons
    TI__Genius 14525 points

    Hi Patrick,

    Good Day. Can you help to provide the best method how to measure the output resistance of DRV5011? Thank you very much.

    Best Regards,

    Ray Vincent

  • 0 in reply to Patrick Simmons
    TI__Genius 14525 points

    Hi Patrick,

    Good Day. They are using Fluke and Keithley DMM to measure the output resistance of the Hall sensor, Fluke reads ~500k ohms and Keithley reads ~50k ohms. Proper way is using a curve tracer instead of DMM, but he needs the App engineer to confirm that. Please advise. Thank you very much.

    Best Regards,

    Ray Vincent

  • 0 in reply to Ray Vincent Aranzaso
    TI__Mastermind 22745 points

    Hello Ray,

    Interesting that you would mention a curve tracer, Tektronix actually offers I-V curve tracer software for their Keithley here.  DRV5011 is a push-pull part, so it will either be a low resistance to GND or VCC depending on the last crossed threshold, thereby sinking or sourcing to the limit of your supply or the device, which we wouldn’t recommend.

    The DMM has a set voltage it applies to the terminal and based upon the a potential produced from current passing through an internal shunt, is able to provide calculation of the current and consequently the resistor of interest.  As you are trying to measure the resistance of a DS channel that varies with the drain to source potential, something with curve tracing capability seems like it would make more sense.  Your customer would need track both the voltage at the output and the current sourced or sinked into the device.  Which actually could still possibly be achieved with 2 DMMS (1 for voltage, 1 for current).

    You could try measuring while the device is powered off to determine what the open drain resistance is.  However, when you force a voltage you might run into the issue with the esd diodes turning on. 

    Can you provide a little more explanation as to why the customer wants or needs this information?