Hello. I would like to use AD9102 as a self-test signal generator to a low noise sensor signal conditioning path.
The sensor is a capacitive sensor, approximately 1.7nF. The frequency range is 10kHz to 200kHz, thus the sensor impedance varies roughly from 9.36kOhm to 468ohm.
I have a low noise amplifier, non-inverting, bipolar rail connected directly to sensor. However, I would like to be able to either disconnect the sensor and inject a voltage signal from AD9102 to the low noise amplifier (signal conditioning + ADC self-test) or keep the sensor connected to LNA and use AD9102 to inject a known current signal into the sensor (basically implementing an impedance analyzer).
My question is this: does ADI have any recommendations on how to accomplish this setup? I am looking for extremely low additive noise analog switches (LNA runs from +-3.3V rails), and how to arrange signal conditioning between AD9102 for both voltage injection into LNA and current injection into the sensor.
I moved your thread to the High-Speed DACs community. Someone here will be able to assist you.
Any thoughts from ADI on this?
Sorry for the delay. Let me consult with my colleagues in the instrumentation business unit and get back to you.
Solved this offline. For reference, the solution was to use op-amp to take AD9102 current output to single-ended voltage output. Current injection was accomplished by 1Mohm resistor in series with DDS voltage output to sensor (1Mohm >> Z_sensor), and voltage injection done with resistor divider between DDS voltage output to sensor. Analog switches used to either use the current injection or voltage injection paths.
Have you considered the AD5940 or ADuCM355? These devices were designed to cover impedance measurements up to 200kHz, it may just be what you need.