ADS4225: CM pin connection

Naizeng Wang

Part Number: ADS4225
Other Parts Discussed in Thread: THS4509,

Hi team,

Customer want to use THS4509+ADS4225 to sample a small voltage signal. THS4509 is to enlarge the signal and ADS4225 is to translate the analog signal to digital signal. How can I set up the CM pin of THS4509 and ADS4225? Can I connect them together? Thanks!

Nison

over 1 year ago

0 Chase W over 1 year ago

TI__Mastermind 21415 points

Hi Naizeng,

Since the ADC input is not self-biased, yes the best solution will be for the VCM pin (ADC output) to connect to the CM pin (amp input) and DC couple from the output from the amplifier to the ADC input. See my figure below.

Regards, Chase

0 Chase W over 1 year ago in reply to Chase W

TI__Mastermind 21415 points

0 Chase W over 1 year ago in reply to Chase W

TI__Mastermind 21415 points

Resistive matching network should still be designed in where I have red box shown above.

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ADS4225: CM pin connection