Our customer bough 2 set of EVAL01-HMC1086F10 to testing.
But VDD short to GND before power supply.
Do you know what happen the symptom?
I apologize for the delayed reply. Our system did not alert me to your message and I was just made aware of it by our administrator.
The active devices in the HMC1086 are depletion mode FETs. If you simply measure resistance from drain to ground with the gate either open or at an insufficiently negative voltage, you will see a low resistance. You should instead simply power-up bias the parts in the following manner:
Vdd1 and Vdd2 can be connected together and a single drain supply used for both.
Vgg1 and Vgg2 can be connected together and a single gate supply used for both
Starting with Vdd and Vgg set for either 0V or open:
Apply Vgg = -8 V (at this low of a gate voltage, the channel will be "pinched-off")
Apply Vdd = 28 V (Once 28V has been applied, Iddq should be very low...single milliamps...since the channel is pinched-off)
Incrementally adjust Vgg more positive until Iddq = 1100 mA (this should occur at Vgg ~= -2.5V).
Apply the RF signal.
For power-down bias:
Remove the RF input signal
Adjust Vgg to -8V (to put the channel into pinch-off
Adjust Vdd to 0V or disconnect
Adjust Vgg to 0V or disconnect.