Problem with ADSP 21262 power supply

I have designed a board with ADSP 21262 processor. Before soldering the processor, I have verified the isolation between core supply point and the external supply point. But once the processor is wired, they show short and the same voltage, 1.2 V. Why this happens? I am giving supply from two external power supplies. In the datasheet, some 200ms requirement is given for turning on of the power supplies. Is it because of this?

  • Hi Nivin,
    There should be no short between VDDINT and VDDEXT.  If you power one without the other, there should be some non-zero voltage on the other domain.  If you measure the resistance with a volt meter, you might see more conduction in on direction than the other because there is an internal ESD diode between them.
    If there is a short (less than 3 ohms), the first thing to look for are VDDINT pins connected to VDDEXT or the other way around.
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