HMC980 vs HMC981

Question

Hi, 
 I am doing some DC tests using an Electronic Load on HMC980 and HMC981 DevBoards, an I'm having different results. 
 HMC981:

Does not matter what sequence VDIG and VDD are applied. It just works. 
 EN pin enables and disables VDRAIN and VGATE as intended, and does not cause it to latch. 
 
 HMC980:

VDIG needs to be turned on AFTER VDD, contrary to graph in datasheet. 
 When disabling the ABC using the EN pin it latches off, requiring power cycle of VDIG. 
 
 Would you know why this difference in the power up sequence and EN pin behaviour? 
 
 Thanks 
 
 Mateus Ohse

DanO2 · Accepted Answer

I would suggest connecting the ABC to an amp and following the recommended bias sequencing.. I suspect that the bias sequencing will work with an active amplifier in line (remember to reverse for power down).)

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HMC980 vs HMC981

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