AD9858_unused power pins connection and saving power measures

Document created by analog-archivist Employee on Feb 23, 2016
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I am using AD9858, and he haven't use the internal PFD and Mixer. So he powered
down PFD and Mixer by Software, the power consumption is decreased, and he
measured the chip's surface temperature by temperature sensor, the temperature
is about 50 degree. He think the temperature is high for him. So he want to
know:
1. For PFD Circuit and Mixer, if he don't supply power for these circuits,
whether AD9858 can work? If OK, which power pins can be float?
2. Comparing Power Down by Software and Power Down by Hardware, which one can
save more energy?

 

We don't recommend un-powering supply pins for circuits that are disabled or
unused.
Keep all supply pins powered.
There's not a whole more to reduce power besides disabling circuits.
You might try…..
1) Turn off the SYNC_CLK
2) Reduce the system clock frequency, if appropriate.
3) Run the 3.3v digital power supply on the low side of the specification.
4) Reduce the DAC full scale current.

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