I am currently evaluating the QPF0219 and have encountered an issue with the PA biasing behavior that deviates from the datasheet specifications. Below are the steps and observations from my setup:
Powered on the QPF0219 following the recommended bias-up procedure.
However, the PA did not draw any Idq at PA_Vg = -2.5 V, even though the datasheet indicates it should draw approximately 1.68 A at this gate voltage.
At PA_Vg = -0.7 V, the PA drew 800 mA. At PA_Vg = -0.1 V, it drew 1 A, still below the expected operating current.
I did not exceed PA_Vg = 0 V, respecting the Absolute Maximum Rating.
after powering off the device according to suggested Bias down procedure, I checked the gate and drain impedances, and they seem to be fine.
There will be some variation on the gate voltage vs Idq response, but what you observe seems strange and would seem to indicate that the device is damaged. Please contact appsupport@qorvo.com stating your company name and location and this issue can be investigated further.
Hi Chris,
Syam from Qorvo visited our facility and personally inspected both the circuit and the QPF0219 device. He confirmed that the device itself is functional but was unable to determine why it’s not drawing the expected Idq. He suspects the issue might be related to inadequate thermal dissipation. However, we’ve ensured proper thermal management by incorporating sufficient thermal vias based on the evaluation board’s Gerber files and additionally, we placed an indium sheet directly beneath the component and above the mechanical base plate to enhance heat transfer. The device is mounted on a 2-layer PCB.
Hi, if the device is overheating you normally get the Idq drifting higher for a fixed gate voltage. Have you checked the assembly thoroughly, to ensure there are no bad solder joints? Have you tried testing another device to see if you get the same problem?
Hi Chris, today, I have tested a fresh QPF0219 IC, and biased it up manually, it started drawing an Idq of 1.68 A at PA_Vg = -1.78V and PA_Vd = 22V. Only thing I did differently is that I set the initial gate voltage to -3.8 V and started tuning up from there instead of -5 V, which was suggested in datasheet (Bias-up procedure section). I did this because datasheet contradicts itself in absolute maximum rating section where minimum PA_Vg is given as -4 V.
I have attached the snapshots from datasheet for your reference; do you think this could be an issue?
I have already highlighted this issue with Syam, even before the amplifiers reached us, but he said we could proceed according to bias up procedure. what is your take on this?
