Hi,
I’m evaluating the QPA2610, QPA2611, and QPA2612 for an application where the PA runs continuously (CW) for 100% duty cycle. The datasheets characterize all three under pulsed conditions only (100 µs / 10%), so I’d like to understand their CW behavior.
Specifically:
- Can these parts be operated CW, and if so, up to what output power for each while keeping the junction temperature within the rated maximum?
- Is there a recommended derating from the pulsed Psat figures for CW operation?
For context, I need roughly 5 W output. I’m trying to decide whether a single backed-off QPA2612 is viable, or whether I should distribute the power across lower-power devices.
Thanks.
This is not straightforward to answer as it depends on variables like the max temp in the application, PCB design, mounting and cooling. You could run these 3 MMICs in CW, but may have to back off the drain voltage to lower the dissipated power, which would also drop the output power.
A single QPA2612 should be capable of 5W CW, using drain voltage of 18V. This assumes that you can keep the MMIC underside (Tbase) to 85C maximum. There are plots of performance for different drain voltages in the QPA2612 datasheet.
PCB design will be very important for CW, I would recommend using a copper coin embedded in the PCB to lower thermal resistance. The PCB would also need a thermal interface down to the case/heatsink, for example epoxy.
As this is not a trivial subject I would recommend contacting appsupport@qorvo.com stating your company name and location. Then your local field applications engineer can assist further.