We are experiencing strange cross talk issue while using ADG726 for switching between different analog sensor to the ADC.
- ADG726 operating in differential mode with 0-5V supply.
- Multiple analog sensors are connected between the SxA (working electrode) and SxB (reference electrode).
- The output DA and DB is connected to a pseudo different ADC in ADuCM355 for performing open circuit potential measurements.
- ADC reference input is connected to internal 1.1v, same is applied to the reference electrode (enables to read negative values as well).
- Cycles through each of the sensor input every few millisecond for ADC measurement.
- Only one sensor connected to the ADC at a time
- When only one sensor is connected to the switch (say S1A and S1B) and all the switches are read, we are getting some voltage measurement in the adjacent switches too.
- This voltage appeared in the adjacent pins are are constant or decaying exponentially but random in nature (some measurement is always made and values is lower than the sensor reading)
- If we change the switch from 1 to any other the number of adjacent pins affected varies as well as the amount
- What could be the reason? crosstalk?
- I verified that the switches are being muxed but could it be because i am not latching the outputs?
- Will the reference dc bias have any affect on adjacent pins
Any help is greatly appreciated. Thanks in advance.