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INA293: Measurement Speed

Malcolm Simpson
Prodigy 10 points
Part Number: INA293

I need to measure the current of a signal with at least 1 nanosecond precision. The signal is a 400kHz square wave with under 20% duty. This signal will have a peak voltage of 50V and a peak current of 4.5A. Is the INA293 good enough to measure this? If not, does TI offer any products that would be capable of this?

  • 0
    TI__Mastermind 29850 points

    Hello Malcolm,

    This very high speed at 1 nanosecond you need 1Ghz which is difficult.  I do not know of anything in this range  Do you need that speed?  Even if you used our high speed amplifiers with multiple gain stages you would still need to worry about the squarewave.  I assume it is a PWM signal on the signal from some sort of bridge circuit.    Most devices do not like the high speed VCM and will disrupt your  signal as most devices AC CMRR will cause you issues.  The other issue is high speed amplifiers working at 50V.  The fasters device we have for the is the INA296 but you will still have issue with AC CMRR.  The INA241 has enhanced PWM rejection  but 400Khz is too fast as for the rejection.  

    Another alternative would be a current transformer for fast signals and combine it with a slower version.

    Regards,

    Javier