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HMC437 troubleshoot


I am using an HMC 437 on the evaluation board (PN105786-HMC438MS8G) to divide a 1.0136 GHz -6.4dBm CW signal down to 337.86 MHz (-1.36dBm) but after ~1 week of continuous operation it no longer acts as a divide-by-3 but as a divide-by-2 with low output power (506.8MHz -27.1dBm). My supply voltage is 5.05V coming from an LM338. 

What could cause a problem like this? Over-voltage or too much input power? Any input would be greatly appreciated

  • Hello,

    From your description it sounds like the unit did see some over-voltage or ESD event.  The HMC437 has a very limited ESD protection, so its possible this maybe the cause.

    You mentioned you were testing the HMC437 on the HMC438 board.  This should work, but I'm wondering if you swapped the HMC438 unit with the HCM437 yourself or if it came that way from ADI?  The reason I ask is to solder a HMC437 onto board would involve a very low ESD environment - proper grounding of the bench and person installing the HCM437 and probably some de-ionizers.  One possibility is the unit became a 'walking wounded' after installation and then died after a week of use.  This is pure speculation based on limited information...

    Can you measure the supply current and all the DC voltages on every HMC437 pin?  This might tell us something more.