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HMC920 Power-up / Power-down

Question asked by payam.mapar on Jul 7, 2016
Latest reply on Jul 15, 2016 by kkaya

Hello everybody,


I asked this question one month ago without any reply. Would someone please take the time to answer it? We are finalizing our board and we still have several questions regarding HMC920.


I am using two HMC920 to power a two-stage microwave doubler: one amplification stage and one doubler stage. Both stages have negative gate voltage. I have several questions regarding HMC920 specifications and capabilities. I begin with the first one in this message and I will ask other question later:


Q1: there are Power Up/Down Waveforms on page 7 (13-5) of the datasheet.



I would like to know which mode (enhancement or depletion) these waveforms are for? In the Power Up waveform, the final gate voltage in negative, so it seems to be depletion mode. But in the Power Down waveform, the gate voltage is positive at the beginning (enhancement mode?), then it becomes negative before turning off! What does it stand for? Could you explain what happens exactly during power down?