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PicoZed SDR Z7035-AD9361 Power Sequencer Update

mbrown

The document linked below explains PicoZed SDR 2x2 System-on-Module (SOM) power up issues that have been occasionally reported. This pertains only to part number AES-Z7PZ-SDR2-G. This document also provides the steps necessary to update the firmware of the power sequencer located on the SOM, which resolves the power up issues. This critical update should be applied to all PicoZed 2x2 SOMs to ensure reliable operation.

 

https://avnet.egnyte.com/dl/9PD26RxEwJ/PicoZed_SDR_Z7035-AD9361_Power_Sequencer_Update_v1.4.pdf_

 

The SOM User Guide has been updated accordingly.

 

/Matt

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  • 0

    Copying 'iampkim' response from elsewhere:

    "I put a probe on my 5V into the SOM.  After my 5V comes up, I see Vin_en go high about 4ms later..  When Vin_en goes high (12V), my 5V droops to 3.5V for about 2ms and ramps backup to 5V.  Around 400ms later, Vin_en goes low again and shuts down the SOM.
    I'm guessing the in-rush current on the 5V to the SOM is causing the droop.  Is a 2ms glitch long enough to shut down the ADM1166?  Once it shuts down, does the ADM1166 wait to see if the 5V is good and try again?"

    ---

    YES! This is almost certainly the problem. If your 5V rail dips beneath the 4.5V threshold the ADM1166 will power down the SOM. It should stay in a power down state until you power cycle the system 5V rail. You could modify the ADM1166 firmware to accomodate your 5.0V supply. A simple time delay would do the trick. You can also set a measurement window on the ADM1166 inputs such that the threshold must be crossed for x ms before triggering.

    /Matt

  • 0 in reply to mbrown

    It looks like the current limit from the bench supply was too low.  I've increased the current limit to 1.5A and the glitch on the 5V input virtually goes away - however, the PG_MODULE led continues to blink.  Is there a document somewhere that details the ADM1166 configurations?

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