ADS1675: Power supply for AVDD pin 53

Hello Lee,

Yes, AVDD pin 53 supplies power for the ADC clock circuits.  Here is the recommendation from the Power Supply section of the datasheet:

Power-supply pins 53 and 54 are used to drive the internal clock supply circuits and, as such, are very noisy. It is highly recommended that the traces from these pins not be shared or run close to any of the adjacent AVDD or AGND pins of the ADS1675. These pins should be well-decoupled, using a 0.1uF ceramic capacitor close to the pins, and immediately terminated into power and ground planes.

I suggest following the above recommendation, but if you prefer, you can use 0Ohm resistors to select between a common AVDD and a separate AVDD to see which approach provides the best performance.  If you do provide a separate 5V supply for pin 53, make sure the voltage on this pin ramps up with the rest of the AVDD pins within +/-0.3V to avoid any possible power-up issues.  

Regards,
Keith Nicholas
Precision ADC Applications

Hello Keith,

Sorry for my late, it seems you misunderstand my question. What I means above is that I will use a single power supply to power multiple ADS1675's pin 53, as well as other digital devices, so I need to know the current of pin 53.

Regards