Interfacing PSoC 5 kit with high impedance sensors

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
Anonymous
Not applicable

 Hi I'm having problems reading a DC high Z signal at the analog opamp ports on the kit while acquiring it for Delsig ADC, I buffered the analog signal in a follower opamp / buffer PGA with no luck so far, what would be the best solution to deal with the high impedance? Will resistors (10M or higher) be enough or I still need an external fA opamp. I'm so far stuck and still unconvinced with the analog specs of PSoC. I'd appreciate your help. Thanks

0 Likes
2 Replies
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

The input impedance of an analog input is comparably high, so no need to put a resistor into the path.

   

Input leakage current (see pins datasheet) for a GPIO-pin is 2 nA @3V which is 1.5GOhms.

   

 

   

Bob

0 Likes
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Post a schematic, or an image of, including the sensor hookup, that way we

   

can help you.

   

 

   

Regards, Dana.

0 Likes