12th December 2013, 22:57 #1
Member level 3
Question on off-chip feedback capacitor connection to on chip current integrator
I need to design a large off-chip capacitor as the feedback capacitor of a on-chip current integrator for a large input current (over 10uA). However, I also need to use the same integrator to detection low level current (1pA). I know the input node Iin is very sensitive to noise. However, pad connection to noise may cause noise collection. What is the best way to design the connection between integrator and off-chip capacitor?
Or, with a current integrator, you may have some good ideas to detect a large input current instead of using a large feedback capacitor. Can you share these ideas with me?
On potential method is to place a switch between the integrator input node and the off-chip capacitor connection PAD and then this switch can be turned off to block noise from off-chip capacitor connection when low input current is detected. Does this method work?
Last edited by hyleeinhit; 12th December 2013 at 23:04.
12th December 2013, 22:57