I made a 6 custom board based on HMC637 PA and HMC920 bias circuit , two of them are working well but the others didn't work and have strange behavior
the first one Vgate stucked to -1.5V VDRAIN =0.7V ( when i remove the PA the vdrain =12.2 volts and VGG1=2 volts)
the others Vgate =-2.3V and Vdrain =0.5 V (PA never removed )
please can some one help me to figure out the problem its very urgent ,below is my schematic.
please note that R8 and R22 in the reference schematic of AD are not used here pins are floating
and I hope they are not the cause of this behavior
any help will be appreciated