Hi, I am using an IVC102 with a photovoltaic sensor in the "reset-and-integrate" configuration depicted as Figure 1 of the IVC102 datasheet for a very low light measurement application (with an internal 10pF capacitor). It seems to work well under normal conditions. However, when the sensor is exposed to an ambient light, it takes about 10 minutes to stabilize and it seems to detect some kind of residue during that period of time. The sensor outputs 10uA and the voltage across its anode to cathode is 430mV when it's exposed to the ambient light (these numbers were measured with the sensor alone). The voltage is higher the IVC102's internal clamp on the pin 2 per its datasheet, but the pin 2 is tied to GND in this configuration. 20uA is much smaller than 200uA which can be applied to pin 2 (pin 3 can take more though). Both the S1 and S2 are closed during the ambient light exposure, expected to discharge any photo current/charge before each measurement. S1 and S2 are closed at the beginning of the measurement when the sensor sees virtually no light. The IVC102's output gradually goes down to "dark" in 10 minutes and it is really stable after that.
The sensor alone seems to respond much quicker than 10 minutes, say in a fraction of a second to become zero in voltage/current, though it's only measured in uA (not pico-amps).
Does anyone have any explanation to this phenomenon? I am asking a similar question to the sensor MFR from the sensor view point, but I wanted to know if there's anything I need to pay attention to for the IVC102 use?
Thank you,
