STMicroelectronics STP9NM50N

Overview

STP9NM50N from STMicroelectronics is an N-channel 500 V, 7.5 A, 0.47 Ω (typ) high-voltage Power MOSFET based on second-generation MDmesh™ technology, designed for high-efficiency switch-mode power supplies and offline converters. It features 100% avalanche tested ruggedness, low gate charge (20 nC), and low input capacitance (570 pF), enabling fast switching in hard-switched PFC and SMPS primary-side applications.

For engineers reviewing the STP9NM50N datasheet, STP9NM50N pinout, STP9NM50N application, or STP9NM50N equivalent, key selection criteria include its 500 V V_DSS, 0.47 Ω R_DS(on) at V_GS = 10 V, 20 nC total gate charge, 1.78 °C/W R_thj-case, and TO-220 package thermal performance in continuous conduction mode flyback and LLC resonant topologies.

Technical Context

This MOSFET employs ST's proprietary second-generation MDmesh™ vertical structure combined with strip layout to minimize both conduction and switching losses. Its 500 V breakdown voltage supports universal-input AC/DC front-end designs up to 400 V DC bus, while the 0.47 Ω R_DS(on) ensures low conduction loss at 7.5 A continuous drain current (T_C = 25°C).

The device delivers 150 mJ single-pulse avalanche energy and supports 35 V/ns dv/dt during turn-off under inductive load conditions. Its 1.2 V source-drain diode forward voltage (I_SD = 7.5 A) and 280 ns reverse recovery time (T_j = 25°C) enable robust body-diode operation in synchronous rectification and freewheeling roles.

Key Specifications

Pinout & Package

STP9NM50N is housed in a through-hole TO-220 package with isolated tab (drain-connected), offering mechanical robustness and direct heatsink mounting capability. The package complies with ECOPACK® environmental standards and supports lead-free soldering per JEDEC JESD97.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage power switching applications.

Compared with STP8NM50 and FQP9N50C, STP9NM50N offers the lowest R_DS(on) × Q_g product among TO-220 500 V MOSFETs, making it optimal for efficiency-critical 65–100 kHz SMPS where conduction and switching losses must both be minimized.

Availability

STP9NM50N is available at Aetrix Electronics and suitable for server power supplies, industrial AC/DC adapters, LED driver bulk switches, and UPS inverter stages requiring stable component supply and long-term industrial lifecycle support.

Supply support for STP9NM50N includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

STP9NM50N belongs to the MDmesh™ high-voltage Power MOSFET product line, engineered specifically for high-efficiency offline power conversion in industrial and computing power supplies where low R_DS(on), rugged avalanche capability, and fast switching are essential.

FAQ

Is STP9NM50N suitable for use in synchronous rectification?

No-STP9NM50N is not recommended for synchronous rectification due to its relatively high 1.2 V source-drain diode forward voltage and lack of optimized body diode softness. Its design targets primary-side switching where low R_DS(on) and high V_DSS are prioritized over reverse recovery performance. For secondary-side SR, dedicated low-V_F MOSFETs like STP16NF06L are preferred.

What is the maximum safe operating temperature for STP9NM50N?

The absolute maximum junction temperature (T_j) is 150°C, and the storage temperature range is –55°C to +150°C. Derating begins above T_C = 100°C, where continuous drain current drops to 5 A. Thermal design must ensure R_thj-case ≤1.78 °C/W and maintain T_j < 135°C under worst-case load and ambient conditions.

Does STP9NM50N require a gate resistor for stability?

Yes-a gate resistor (typically 10–47 Ω) is required to dampen gate ringing caused by parasitic inductance and the MOSFET's 6 Ω gate input resistance. Without it, overshoot exceeding ±25 V V_GS rating may occur, risking gate oxide damage. Layout best practices include short gate traces and local decoupling near the driver IC.

Can STP9NM50N replace STP10NK50Z in existing designs?

Not directly-while both are 500 V TO-220 N-channel MOSFETs, STP10NK50Z has higher R_DS(on) (0.55 Ω), higher Q_g (35 nC), and different dynamic characteristics. Substituting STP9NM50N may improve efficiency but requires revalidation of gate drive timing, dv/dt stress, and thermal margins due to its lower R_DS(on) and faster switching.