The following circuit is a preamplifier that we are currently using. In real practice, we do not have the photodiode connecting with OpAmp directly on board. Instead, the photodiode is connected with the OpAmp through a connector.
The input and output of the OpAmp are both connectors which will be exposed to user connections. Recently I am studying issues on ESD. Then I think the input and output of the OpAmp shall be prone to ESD. I am using a ADA4062.
- How to design to protect the OpAmp input from ESD?
- Can I use some RC filters shown in the diagram, before the input of the OpAmp?
- How to design to protect the OpAmp output from ESD?
To be clearer, here comes updates on system information:
- The capacitance of the photodiode is smaller than 1pF, which is to be designed working at 1GHz bandwidth.
- However, we will only use the low-frequency region, which is below 100kHz.
- The linearity of the system is very important, which means the second order, third order distortions are disastrous to the system. It is preferred that the total distortion is below -70dB.