MEXICOWANDERER wrote:
the MOSFET unit I recommended has a thermal operation limit of 175C AND AND AND AND a Vf that is extremely low. Less junction Vf SIGNIFICANTLY lower. The AREA of the junction in the MOSFET I recommended is more than 250 percent larger.
Ya think maybe the original Chino MOSFET junction temperature limit may be a -little- lower than 175C?
I DO NOT TRUST THE CHINESE to spend a single YUAN RENMINBI more than they have to.
Yes of course heat sinking is vital. But START with a decent component and build from there. Remember the porcupine heat sinks Landy mused over? With Arctic Silver ADHESIVE thermal compound they can become a reality.
The 41 amps was a MOSFET undergoing THERMAL RUNAWAY.
I haven't looked at the MOSFET described so I may be way off, but most times the gate charge (capacitance) is larger in a physically larger device which means it will have higher switching losses when operated at the same switching frequencies even though Rds(on) is lower.
Key specifications for better performance in a switching power supply MOSFET.
The same or higher VDS (voltage drain-source) and ID (peak current drain) and the same or lower Rds(on) (resistance drain-source when saturated) and QG (gate charge or gate-source capacitance).
