Hi,

I am trying to understand the math in calculating the output power on Page 68 of the AD9164 Rev A datasheet. The datasheet says with a 100 Ohm differential source termination, the DAC ac current source sees 50 Ohms. It states that the ideal peak ac current is 20 mA when the AD9164 is programmed for an IOUTFS = 40 mA. So, then it gives that the maximum power delivered to the equivalent load is 10 x (RINT / (RINT + RLOAD)) = 8 mW. What is the "10" in this equation? And if i use 100 Ohms for RINT and 50 Ohms for RLOAD, i get 6.667 for the result. What am doing wrong? Now, i didn't take into consideration the BALUN equivalent impedance which is 50 ohms. With this, the equivalent load would be 25 Ohms. Then the equation above would make sense.

Appreciate any insight.

The '10' in the equation is 10 mW. You are correct that the formula uses the equivalent load when calculating power delivered to the load, so the 25 ohms impedance is the correct value to use.