Other Parts Discussed in Thread: VCA824, OPA656
Support Path: /Product/Device selection assistance/Find an amplifier/filter solution/
We are building an application where our bio-sensors give us current in the range of 50-200 pA. We need to design a front end that would convert this small current to voltage of appropriate level which can be fed to ADC for digital conversion for processing. Our query is as follows:-
We looked for TSW7001EVM from Texas Instruments, it has OPA656 Op-amp on board configured as TIA. OPA656 has bias current of 5pA. Please tell us whether this TIA would be appropriate for our application? If yes, then the other issue is that feedback resistance used in TIA is 50K Ohms as a result the output voltage of OPA656 will be in micro volts but it will be insufficient to drive the voltage amplifier on board i.e. VCA824 (as VCA824 has input bias voltage of 15mV). Please comment. Also looking at our requirement can you suggest any other EVM as an alternate to TSW7001EVM.
Looking forward for a quick reply.
Best Regards,
Sagar