ADF4108 evaluation board overvoltage

Hi

Can you share a screenshot of the Charge pump output for better clarity, Also, do you mean the Lock Detect LED or Power supply LED?

There are 5 Regulators on board, you may need to probe each to make sure they output the correct voltages (There should be one 5.0V and four 3.3V). If these are working as expected, then I suggest you probe your communication pins (CE, LE, CLOCK and DATA) to make sure the correct data is being sent to your device.

To confirm you have set things up correctly, refer to the ADF108 user guide https://www.analog.com/media/en/technical-documentation/user-guides/UG-160.pdf and also the board schematics.

Let me know how you get on.

Cheers

Hey Jude, thank you for your answer! Here's the screenshout of the charge pump output. As you can see it's a DC signal, at around 2.2 V with only noise on top, anything that resembles pulses at the PFD frequency (which should be 1 MHz here)

Yes, the LED I am talking about is the Lock Detect LED, powered up by the MUXOUT output of the ADF4108, which can be programmed to output several signals other than lock detect. Two of these are AGND and DGND ground connections, which should turn off the LED, but this does not happen.

As for the regulators, I measured the ouptuts of all the 5 IC on the board and they provide the expected voltages.

I lastly tried to measure the communication pins. This is what I observed:

- CE pin is always on, even when I try to write some data via the software, I don't observe any change in this pin

- CLK is low, and gets activated when trying to write some data. I can observe 3 pulse trains, as you can see here (yellow is CLK and green is DATA)

- DATA is high, and gets low when CLK rises, except for some of the cycles, which I believe correspond to 1 bits. The following image is a zoom-in in the first train pulse of the previous image.

- LE is low, and is briefly acivated (a single pulse) at the end of each CLK pulse train.

I never worked with communication protocols, so I wouln't be able to tell wheter these are the correct data I am trying to write, but according to the datasheet the protocol at least seems sensible (even though I am not sure about the role of CE, which is not specified in the protocol explanation). Hope this helps, thanks again,

Leonardo

Hi Leonardo,
From screenshot you sent, it shows you are correctly sending data to the ADF4108 chip and the SPI communication protocol is working correctly. The final checks you could do to confirm the state of the chip is to look at the current consumption on your power supply, if you could recall what it was when you first tried to program the board out of the box and compare that to what it is now, or if there is no significant increase in the current consumption when you initialize the chip, this could definitely mean that the chip is damaged.

Jude

Yes, sadly the current consumption is higher, about twice as much the original value (even though this happened already before the overvoltage, it is indeed the very reason why this occurred, as the DC source reached the current limit I had set). Thank you again for your help, I will try to substitute the ADF4108 chip.

Sure, let us know if you need any other assistance. 

Regards

Sure, let us know if you need any other assistance. 

Regards