Post Go back to editing


How to check that LTC6560 is properly grounded via thermal pad? I put one pull down resistor-60Kohm to input (Din), but the voltage at this pin is still showing is 1.5 Volt !!! I am using this IC for APD with positive bias. (equal to Vref-pin of IC), please suggest.

  • Hi ,

    The LTC6560 input is biased to 1.5V nominal internally when Active:

    So, you're measuring a valid input voltage. At least electrically, it seems like the exposed pad is properly grounded.

    Also, from datasheet page 14:

    "To maximize dynamic range, the LTC6560’s input is limited
    to negative current pulses (current flowing out of
    the LTC6560). When using a negatively biased APD, the
    TIA input can be AC or DC coupled to the APD cathode.
    When using a positively biased APD, the input must be
    AC coupled to the APD’s anode."

    Let me know if you have any quesitons.