The AD9081 on our board is malfunctioning due to the following conditions.
We suspect an internal power supply malfunction, but could you please advise the cause of this issue and any additional points to check?
- After powering on the device, it heats up even when no clock is being input (surface temperature measured with a thermocouple is approximately +72°C).
- When attempting SPI access, the AD9081 does not respond (the AD9081 does not output any data).
*The same problem occurs when performing a hard reset (RESETB from "L" to "H") and then a soft reset by changing the SPI 0x0000 from "0x81" to "0x00" before issuing the command. I tried both 3-wire and 4-wire SPI and experienced the same symptoms.
- All power supplies were confirmed to be normal, but the internal power supply was showing abnormal values as shown below.
NVG1-OUT1/2: +0.36V (should be -1V)
BVNN2-1/2: +0.25V (should be -2V)
BVDD1-1/2: +2.0V (should be +3V)
- The above condition persists regardless of whether or not there is a clock input (4.8GHz) to the AD9081.
- The same symptoms were observed on all three prototype boards.
