My QPA1015L is imbedded in an amplifier circuit. It has recently started drawing down the magnitude of Vg_pinchoff at -6.4v, and Vg_biasON at -2.8v, to Vgs = -0.64v. Ig is 5.7mA, which is causing this reduction in Vgs due to a drop in the gate current limiting resistor, and the input impedance measured with an ohmmeter on the de-embedded QPA reads around Rgs = 14ohms. A fresh new unused unit measures ~500kohm Rgs. Is my low 14 ohm measurement an indication that this unit has failed? Is the ohmeter a safe and valid test? in the old days we used curve tracers to verify biased transistor operation, but I haven’t seen one of these in many years. what is the correct way to test a GaN FET? David M
Yes, if you are measuring very low Rgs then the device is badly damaged. Using an ohmeter is a safe and valid test for Qorvo GaN FETs and MMICs, you just need to be careful with ESD when probing the pins. The Rgs should be high impedance, and Rds very low impedance (as uses depletion mode pHEMTs).