A week leakage current inside the chip from ADC PIN ofSTM32F103ZET6?

[Richard Liao]

Posted on May 31, 2018 at 15:40

Hi ,I used STM32F103ZET6 PIN28 PC2  ADC funtion to get the voltage of CMP_V.  The voltage of this pin(PC2) is 0.032V when R335 is 100 K,CMP_V is olso disconnected from any circuit.   I try to change the value of R335 to 68K,  t

he voltage of this pin(PC2) is change to 0.022V.   So  I deciede to reduce the R335, t

he voltage of this pin(PC2) is decrease too .

Use a emitter follower to PIN PC2，may  eliminate impact of this voltage;     

Does any one meet this problem,and resolve it ?  I guess there is a week leakage current inside the chip from this PIN PC2 for some reason that made by register configuration.

[T J]

Posted on June 01, 2018 at 03:10

I guess there is a week leakage current inside the chip from this PIN PC2 for some reason that made by register configuration.

if you have a scope, you may be able to see the noise on that pin, this noise is rectified inside the chip and the voltage is added.. so yes, looks like a leakage current. even a small cap would help, like 10pF