Urgent: ADRF5027-EVALZ stops working after few iterations

Hi,

We’ve been iterating with 2-3 EVALZs for ADRF5027 and all of them stopped working after one or two experiments. We’d like to figure out why this is happening every time. So, here is the details of our operational process and our observations:

The chip requires dual-supply voltage of +3.3V and -3.3V. We’ve been using Keysight E36300 Triple output power supply by setting the corresponding voltages and the maximum current of 0.001A (this is the minimum value the power supply can be set to).

However, after we connected the loads to the eval board, we noticed that the voltages (sometimes the positive and sometimes the negative voltage) fluctuate a lot between the absolute values of 1.5V and 3.3V and sometimes it fixes on lower values (~1.6V). Our speculation was that the current is set too low. So, we increased the current to 0.1A (and sometimes 0.5A), which solved the voltage fluctuation but the chip draws a lot more current that the typical values in the datasheet (the typical values are 2uA for positive and 100uA for negative supply current, while the chip sometimes draws 0.1A to 0.3A). So, my questions are:

  1. Should we limit the supply current based on the datasheet?
  2. Is it OK if the chip draws more current than the typical values?
  3. We followed the power-up sequence based on the data sheet, by enabling the GND, VDD, and VSS sequentially, then powering up the digital control inputs from a Raspberry Pi (with 3.3v power on control pins - we also have a connection between the chip’s GND pin and RPi’s GND). However, we noticed that sometimes the supply powers drop to 1.6V, while the control pins are still set to 3.3v sourcing from RPi. Could that cause any problem and what is the best practice to avoid damaging the chip?
  4. Should the power driving the VDD, VSS and the control pins come from the same source?
  5. We haven’t add any bypassing capacitor on the supply lines assuming that the Keysight power supply is already filtering high frequency noise. Do you think that could be the reason of frying chip?
  6. What is your recommended process for powering the chip?

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