Does anyone know the maximum external resistor value that can be used with the OPT101? I am designing a low cost differential light sensor to detect starlight. I am currently not getting enough gain using an external 20M resistor. The circuit uses two OPT101 with outputs run into an INA118 for more gain. The data sheet shows 50M. I think I need closer to 1G ohm.
I want to avoid avalanche diodes due to their high cost and HV power supply. The circuit works on brighter stars like Sirius, but stars like Polaris, which are 8 times times dimmer do not work well.
Any suggestions would be appreciated.
Jerry
I want to avoid avalanche diodes due to their high cost and HV power supply. The circuit works on brighter stars like Sirius, but stars like Polaris, which are 8 times times dimmer do not work well.
Any suggestions would be appreciated.
Jerry