QPA2611 EVB- Substrate type and thickness

RF Solutions RF Power Amplifiers
1

Hi,

Could you please provide information about the substrate type and thickness of QPA2611 EVB?

Regards,

2

Rogers Corp RO4003C, 0.008inches thick.

3

Thank you very much Chris.
I have one more question about thermal management of the IC.
Do you recommend using a thermal pad between mechanical chassis and the top of the package?
Regards,

4

The dominant thermal path is through the bottom of the package, into the PCB. The thermal path to the package top is fairly insignificant, so putting a thermal pad on the package top will not help much. The PCB thermal deign is much more important, plus the thermal interface between PCB and chassis. The QPA2612 eval board is very thin, 10mils, and has a dense array of copper filled vias under the MMIC in order to minimize PCB thermal resistance. The PCB is mounted to the carrier with epoxy to give a good thermal interface.

5

Thanks Chris for the detailed information.
Junction temperature is given for under RF, 100us/10% in the datasheet.
Do you have the junction temperature value for CW? (32 APSK)
Regards,

6

I don’t have that information. You could estimate using this app note. The plot on page 4 shows typical change in channel temp with PW and DC, out to continuous. Using the QPA2612 in CW you need to be even more careful with PCB design, thermal interfaces and cooling. It would be a good idea to use a PCB with embedded copper coin to help get the heat out of the package. It would also be a good idea to limit the drain voltage to 20V or 22V in order to reduce the power and heat dissipation.

7

Thank you so much for your valuable support.
Regards,