ADC12DL3200: Biasing the inputs

Charan MMJ

Part Number: ADC12DL3200
Other Parts Discussed in Thread: LMH3401, LMH5401

Hi,

I am using ADC12DL3200 part in my custom design. ADC gets input signal (of bandwidth DC to 750MHz) from a demodulator, so I can only use DC couple interface. Demodulator output has a bias voltage of 0.9V, but the input common-mode voltage of ADC12DL3200 is 0V. So I am using resistive translation circuit as given below

Please confirm if the values given are proper. (Considering Current of 10mA).

Thanks in advance

7 months ago

+1 Rob Reeder 7 months ago

TI__Mastermind 27420 points

Hi Charan,

Effectively this resistor divider works, but it doesn't account for the output and input impedance of the demod, nor the ADC.

It might prove better to use an amplifier to DC couple and level shift between the demod and ADC to ensure the two different common mode voltages are held.

I would use either the LMH5401 or the LMH3401.

Regards,

Rob

+1 Charan MMJ 7 months ago in reply to Rob Reeder

Prodigy 90 points

Thank you Rob

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ADC12DL3200: Biasing the inputs