DAC 1220

If you want to use a single clock for eight devices, you will need at least a clock buffer (like CDC340). Each clock output of the buffer is connected to an Xin input of a converter. You may want to put an RC filter from the buffer to Xin.

Regarding Vref, I wouldn't share more than one Vref for each two converters, and this after checking that the load from two converters is OK for the Vref. I think that if you share more you have two problems: more load to Vref generator, and also long connections that can catch noise.

Thank you Albert.

Just to add to what Albert has stated.

The delta sigma structure of the DAC1220 samples off of the reference at a high rate. It is important that the reference pin has adequate drive strength to avoid any droop on the line. You may be able to get by using one reference device (like the REF50xx) but with a couple buffer amplifiers in parallel and well placed caps at the inputs of the DACs. Maybe use three total buffer amplifiers; two feeding three DACs each and a third feeding two DACs. OPA350 could be an option for the amplifier to use with 1-10uF capacitors at the Vref inputs of each DAC1220.

Regards,

Tony Calabria

Thank you very much!