ADS5474 input impedance vs Frequency

Frank Xie

Prodigy 75 points

Other Parts Discussed in Thread: ADS5474

Hi, team,

One customer want to know the input impedance of ADS5474 in different input frequencies. Can you help me?

Also, customer want to know whether ADS5474 is switched-capacitor ADC?

Many thanks!

over 15 years ago

0 Hui-Qing Liu over 15 years ago

TI__Expert 6040 points

The analog input structure of the device is an input buffer following by a sample and hold circuit. The analog front stage is shown in fig 31. If estimate analog input impedance, we can use total input capacitance parallels with input resistance 2x 500 ohm. For more accurate calculation, we have a S11 simulation result of the stage from 100khz to 1.5Ghz, please the plot in the file .

Regards,

Qing

ADS5463_5474_S11_ Simulation for customer.doc