Hi .

I wonder the power consumption of AD9788.

Show the power consumption in AD9788 datasheet.

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DC SPECIFICATIONS

POWER CONSUMPTION

1× Mode, fDATA = 100 MSPS, PLL Off, IF = 2 MHz 375 450 mW

2× Mode, fDATA = 100 MSPS, Inverse Sinc Off, PLL Off 533 mW

4× Mode, fDATA = 100 MSPS, Inverse Sinc Off, PLL Off 754 mW

8× Mode, fDATA = 100 MSPS, Inverse Sinc Off, PLL Off 1054 mW

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(in datasheet)

My system main power is 5voltage. So if DC SPECIFICATIONS is correctly, maximum consumption current is 210mA.

But actual maximum consumption current is more than 210mA.

Current measure condition is below.

Only 1 dac operating and 8x interpolation, default scale setting, and default gain, signal is not output..

then the current consumption is 680mA.

Another case is below.

Only 1 dac operating and 8x interpolation, default scale setting, and default gain, signal is output.

then the current consumption is 1084mA.

I just don't understand.

My calculate is incorrectly?

To calculate current you need to seperate the Pd of 1.8v supplies and 3.3v supplies.

You currents are much to high. look on page 52 at figure 75 and 76 to determin current. The 1.8v supplies DVDD18 and CVDD18 draw most of the current. at 8x interpolation and 100MSPS data rate the Pd is about 650mw shown in figure 75,.with 1.8 supply this is 360ma of current in these two supplies

In the AVDD33 the current is 51ma with 20ma full scale current . Tuen off one DAC and should drop to 31ma.

You are measureing 1084ma???

If you are putting 5v on the AD9788 supples you will damage the part. the AVDD33 max voltage is 3.47 andd the DVDD18 supply is max 1.91v.