The J version of Ubox V2 75V

The red is come back.

The "J" is mean for the mosfet name: JMSH1001ATL.

For the mosfets, we have choose the JMSH1001ATL, this is almost the best one we can find in china now. When we start the design we have 4 mosfets to make choice: JMSH1001ATL, MDT10N023RH, MT08N017RH, S92010LAT, the first two are 100V, the later two are 85V, in the datasheet, their on resistances are closing, in real test without heatsink case, the heating speed from slow to quick is:  JMSH1001ATL,MT08N017RH, S92010LAT,  MDT10N023RH, but still not very different, MDT10N023RH has 1.7 on resistance, so it is the fastest, but within 5-10% time compared with others.

When installed in the case, their heating difference was changed dramtically, the key factor is the thermal conductivity of the package, because the Ubox's heat sink is on the mosfet's back, JMSH1001ATL is the most closed one to the original mosfet fdbl0150n80.

For the working environment, there are two heating scenes, constant and burst, The constant heating is from the average operating current by the circuit and mosfet's on resistance, and mainly slowly desidissipate to the surroundings. The burst heating is from the burst currnet, such as accelerating, climb a slope, the burst heating is sinked by PCB, case, then slowly desidissipate to the surroundings.  So compare to the orginal FDBL0150N80, the JMSH1001ATL will a little weaker at burst current(mosfet heating quiker due to the package heat conduction difference), and almost same constand heating.

Al thouth the JMSH1001ATL is the most expensive one among them, we have made the choice on it by its voltage tolerance(true 20V redundancy), and the quality reputation, JieJie Microelectronics has a good reputation in China's automotive electronics market. We are cherishing the Ubox's achievement, we are afraid to ruin it.