Hi guys, I'm building an electrometer that measures the difference voltage across a ~100pF capacitor, and needs to avoid significant leakage for at least 30 seconds. Therefore the input/leakage specs are as follows:
Input impedance > 1TΩ
Input bias current < 100fA
Therefore, I'm looking at the INA116.
The INA116 says it has "INPUT OVER-VOLTAGE PROTECTION: ±40V". But it doesn't say anything about what happens if this is exceeded, or how the protection works. Are there protection diodes to shunt current away from the inputs, or does the device just blow out suddenly? If I put say 100kΩ or 1MΩ in series with the inputs, will that be sufficient against HBM type ESDs?