We wish to employ liquid cooling which is why the GaN FETs will be mounted on an IMS board. I have the following questions for your technical team in this matter: 1- The pitch between the FET pads is only 5mils. Will that cause any issues during fabrication/operation on a single layer IMS board? 2- I searched for evaluation boards from EPC that utilize EPC2022 GaN FETs but could not find any on the website. Can you please tell me the reason why EPC has not utilized the IMS technology? Is it because the GaN FETs from EPC are not meant to be used in conjunction with IMS boards? If so, what is the reason?
The best way we’ve found to do liquid cooling is to use a plate, and thermally couple it to the top of the FETs. This method takes the heat directly from the FETs. On the other hand, I think what you plan is to have the heat go from the FET through its solder connections, into the top of the board, through the board, and to the board’s metal plate. And then the board’s metal plate join to another metal plate (that carries the liquid cooling). The extra layers increase the thermal resistance, and IMS boards aren’t ideal due to the cost and other compromises. Your board manufacturer and assembly house can confirm if they can support the pin pitch; there are many that have that capability.