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How to estimate my DAC's power consumption?


Our part numbers are AD5391-3 and AD5383-3. Though we are using AD5391-5 and AD538-5, here, i only want to use AD5391-3 as example to ask my questions.

1. What's the mean of "boost off" and "boost on"? How can I know if my chips are in boost on or boost off?

2. Datasheet only gives the power requirements when chip with output unloaded/boost off or with output unloaded/ boost on. I want to know the power requirements when chip is with output loaded.

My system seems meeting with power requirements issue. There two group PCBs, they are same. The only differrent is one group use 3A output for +3.3V, and another use 5A output for +3.3V. Now, the 5A group have good system resolution, and the 3A group have worse system resolution.

Please help us on this, thanks in advance.

  • Hi,

    1. Boost on means you have enabled current boost control bit CR11. See table 25 on the AD5391 data sheet for more details.

    2. When loaded, you will have to compute for the current consumed by the load. For example you have set the output to 5V and the load is 500ohms, then you will have a load current of 1mA. This 1mA is also taken from your supply.

    What is your load? can you provide a schematic of your system?

    Best regards,