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AD converter for synchronized sampling?

Jari Honkanen
Prodigy 100 points
Other Parts Discussed in Thread: ADS7865, ADS7891, ADS7882

I have tried to find a 12-14 bit resolution AD-converter for synchronously sampling a pulsed signal. The sampled signal is from a Buck switching supply current measurement. The signal is almost square wave shaped and has 400kHz frequency which I need to sample synchronously with 100kHz sampling frequency. The ad converter needs to have a sample and hold circuit so that the measurement can be accurately timed to the center of the pulsed measurement with the 100kHz sample clock signal. The converter would be synchronized to a 100kHz clock, but it should have fast conversion time (under 1000ns) as it is part of a control system and there is additional delay due to isolation and possible buffering. The ad converter also needs to have a parallel interface for the data.

  • 0
    TI__Guru 55466 points

    Hi Jari,

    ADS7865 is a dual simultaneous sampling 2MSPS 12 bit device with 3+3 or 2+2 channels and parallel interface.  Conversion time is as low as 406ns (13 clks at Fclk=32MHz). Full-scale Input range is +/-VREF; where VREF=2.5V; absolute input range -0.1 to AVDD=0.1V. The user controls/triggers the conversions by toggling the CONVST pin.

    The ADS7882 is a single 12-bit SAR converter with a parallel interface, 0-2.5V input range, offering sampling rates up to 3 MSPS with conversion times to 280ns.  The ADS7891 is a similar device with 14 bit resolution and 273ns conversion time.

    Best Regards,

    Luis