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 visnu,
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.
Regards,
Hooman
