Re: Request the schematic review with AD9251-80 and ADA4937-1

Hi Se-woong,

I am looking more at the ADC portion of the schematic. I think it looks pretty good, with the following comments/questions.

• The CLK+/- pins are internally biased, so they should be AC coupled to the clock source. I do not see AC coupling capacitors in the schematic, for the clock.
• The VCM pin on the AD9251 is connected directly to R328, R306, R317 and R308. This is OK. One additional thing I would consider is adding pads for additional series resistors after the fanout to channel A and channel B. These could be populated with 0Ohms initially. The intention is to give the flexibility to add some resistance for isolation between channels, if desired.

• What are the differences between this schematic and the one that was used before for the AD9251-65?
• What is the supply voltage for the ADA4937?
• What is the amplitude of the analog input to the ADA4937?

Thank you.

Doug