ADS5482: Front End Circuitry for Input pins of ADS5482

BALVAN SINGH

Part Number: ADS5482
Other Parts Discussed in Thread: LMH6553, THS4541

Hi Ti team

What will be the front-end circuitry look like if I am connecting LMH6553 differential output to ADC input? My Signal BW is 20Mhz and the Sampling frequency of ADC is 105MHZ.

PFB image and please check if is it okay ?

warm regards,

Balvan Singh

over 4 years ago

+1 Chase W over 4 years ago

TI__Mastermind 23920 points

Hi Balvan,

Yes, this should be stable since the 100 ohm resistors are acting to isolate the capacitive loading of the ADC from the amplifier (too much capacitive loading on the amplifier output will cause oscillation. See this article - Why Op Amps Oscillate). Be sure to place the VCM capacitor (.1uF) as close as you can to the ADC but to also place one at the LMH6553 as well for best results. Here is a link to download the schematics for our ADC364xEVM, which includes a fully differential amp option using the THS4541. You may find this to be a helpful reference while designing the front end for your application.

Regards

0 BALVAN SINGH over 4 years ago in reply to Chase W

Prodigy 130 points

Thanks

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ADS5482: Front End Circuitry for Input pins of ADS5482