The STU417S is HeroMicro a high-performance P-channel power MOSFET fabricated using advanced high-cell-density trench technology. Designed for high-efficiency, high-current switching applications, it features –40V blocking voltage, –38A continuous drain current, ultra-low on-resistance (<20 mΩ @ VGS=–10V), and low gate charge, making it ideal for battery protection, high-side load switches, motor control, inverters, and industrial systems.
1. Key Specifications (from STU417S.pdf)
Drain-Source Voltage (VDS): –40 V
Continuous Drain Current (ID):
–38 A (TC = 25°C)
–27 A (TC = 100°C, derated)
Pulsed Drain Current (IDM): –150 A (limited by SOA)
On-Resistance RDS(ON):
<20 mΩ (typ.) @ VGS = –10 V, ID = –8 A
Gate Threshold Voltage (VGS(th)): –1 to –2.5 V (@ ID = –250 μA)
Total Gate Charge (Qg): 13 nC (typ.) @ VGS=–10V, VDS=–20V, ID=–8A
Body Diode Forward Voltage (VSD): ≤ –1.2 V @ IS = –10 A
Power Dissipation (PD):
63 W (TC = 25°C)
32 W (TC = 100°C)
Thermal Resistance (RθJC): 2.38 °C/W (junction-to-case)
Operating Junction Temperature (TJ): –55°C to +175°C (industry-leading)
Package: Pinout labeled DSG; likely TO-220AB, D²PAK, or similar power package
2. Key Usage Guidelines
(1) Ideal for High-Side Switching
P-channel MOSFETs are naturally suited for high-side switch configurations (source to V+, drain to load), eliminating the need for bootstrap circuits.
Turn on when VGS ≤ –|VGS(th)| (typically ≤ –2.5 V); full enhancement requires VGS = –10 V.
(2) Good Logic-Level Compatibility
Ultra-low RDS(ON) at VGS = –10 V ensures minimal conduction loss. Even at VGS = –4.5 V (common in 5V systems), performance remains acceptable.
Use an NPN transistor or dedicated driver IC to interface 3.3V/5V logic signals to the high-side gate.
(3) Exceptional High-Temperature Capability
+175°C maximum junction temperature enables reliable operation in harsh environments such as automotive under-hood or sealed industrial enclosures.
(4) Thermal Design Is Critical
At –38 A, power dissipation can reach:
P=I2⋅RDS(ON)=(38)2×0.02≈28.9 W
With RθJC = 2.38 °C/W and TC = 25°C, TJ ≈ 25 + 28.9 × 2.38 ≈ 94°C—within safe limits.
Must be mounted on an adequate heatsink with proper thermal interface material for sustained high-current operation.
(5) Body Diode for Freewheeling
Built-in body diode (VSD ≤ –1.2 V @ –10 A) provides a path for inductive kickback from relays or motors. Reverse recovery characteristics are not specified—use caution in high-frequency switching.
(6) Respect Absolute Maximum Ratings
Do not exceed –40 V VDS (including transients).
–150 A IDM is for short pulses only (microseconds)—not for continuous overload.
3. Typical Applications
High-side protection switch in Li-ion battery packs
Main power disconnect in automotive electronics
High-side load driver in industrial PLC output modules
Redundant power path selector in server/telecom PSUs
DC-link switch in inverters or UPS systems
4. Summary
The STU417S stands out with its –40V/–38A rating, <20 mΩ ultra-low RDS(ON), 13 nC low Qg, industry-leading +175°C junction temperature, and excellent 2.38 °C/W thermal resistance. When implemented with proper gate driving, robust thermal management, and protection circuitry, it delivers a highly efficient, compact, and reliable solution for demanding high-side switching applications.
