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Driving ADCMP553 with 3.3V CMOS.

I'm trying to find a robust way to feed the input of a ADCMP553 from a microcontroller.  All systems use Vcc=3.3V.

The MCU generates a 3.3V pk-pk square-wave.  Frequency is fairly low--about 1KHz.

I need to attenuate the signal so that it does not exceed 1.3V (maximum Vin).  This is a problem as adding a voltage divider raises the output impedance of the CMOS driver and allows stray capacitance to change the delay timing by several nsec.

The best solution so far is to simply drive the +IN directly with 0V-3.3V square-wave.  Seems to work, but this is out of spec as I'm driving beyond 1.3V.

Any other suggestions?

  • Hi,

    These are the possible solutions I could think

    1) What are the R values for the divider you tried? Have you tried lowering the R values? Though this could mean increased current. You may also add a buffer in between the MCU and divider.

    2) Add a level translator, here is the link of ADI level translator portfolio. However, this could mean you need additional component on your board so it could probably be a drawback on your side.