Issue link: https://iconnect007.uberflip.com/i/1464867
86 PCB007 MAGAZINE I APRIL 2022 tom corner of the device are extensions of the actual metal contacts. erefore, the FET (in Figure 4) is soldered directly to the 800-micron thick Cu alloy; the resulting electrical and ther- mal path has been optimized. is reduces the resistance in the system (reduces heat gener- ated) and reduces the resistance in the thermal path to remove the heat from the device very efficiently. Furthermore, the ASEP material used for the application can be a thermally con- ductive plastic (such as LCP) which spreads the heat generated by the FET. In effect, the ASEP material itself can be the heat sink or spreader, making it possible to reduce the tem- perature of the heat-generating devices. e ASEP microPDB is a power control device that looks very much like an automo- tive connector (Figure 4) but within it a micro- processor and FET provide local interconnect network (LIN) control and high-current solid- state switching that are highly reliable, self- protecting, and cost effective in comparison with a current microPDB containing a relay and fuses (as seen in Figure 5). e micropro- cessor provides LIN control which eliminates the need to run control lines to each device. Electrical, Thermal, and Mechanical Testing ree main tests were performed to evaluate the electrical, thermal, and mechanical performance of the ASEP microPDB. First, tempera- ture rise testing was performed on the package. e ASEP microPDB was powered with 12 volts from 0 amps to shutdown in 5A intervals and 30-minute intervals. ermo- couples were attached to the micro- processor and the FET to measure the temperatures. Tests were con- ducted at both 85°C and 110°C ambient. According to specifica- tion, the temperature rise should not exceed 55°C above the ambi- ent temperature. In addition to the tempera- ture rise test, both thermal shock and vibration Figure 4: The FET is soldered directly to the thick copper alloy contacts. This results in low thermal and electrical resistance between the heat-generating FET and ambient. Figure 5: a) Current PCB-based microPDB with relay and fuse; b) an ASEP microPDB with FETs.