STMicroelectronics STU4N52K3

Overview

STU4N52K3 from STMicroelectronics is an N-channel 525 V, 2.5 A MDmesh™ K3 Power MOSFET in IPAK (TO-251) package, featuring 2.6 Ω max R_DS(on) at V_GS = 10 V, 100% avalanche tested, and integrated Zener-protected gate. It delivers high dv/dt immunity (12 V/ns), low output capacitance (28 pF), and enhanced diode reverse recovery (trr = 173 ns at T_j = 25 °C), enabling robust operation in offline SMPS flyback and PFC stages.

For engineers reviewing the STU4N52K3 datasheet, STU4N52K3 pinout, STU4N52K3 application, or STU4N52K3 equivalent, key selection criteria include its 525 V blocking rating, 2.6 Ω on-resistance at 10 V gate drive, IPAK thermal resistance (R_thj-case = 2.78 °C/W), avalanche energy rating (E_AS = 110 mJ), and Zener-protected gate for ESD resilience.

Technical Context

This device employs ST's MDmesh™ K3 vertical superjunction architecture optimized for high-voltage switching efficiency. Its 525 V V_DS rating and 2.1 Ω typical R_DS(on) enable high-power density in 85–265 VAC offline converters. The built-in back-to-back Zener diodes clamp gate-source voltage to ±30 V, eliminating external protection components.

Dynamic performance is defined by C_iss = 334 pF, C_oss = 28 pF, and Q_g = 11 nC - parameters tightly coupled to fast switching (t_d(on) = 8 ns, t_f = 14 ns) and low switching losses. The source-drain diode exhibits trr = 173 ns and Q_rr = 778 nC at 25 °C, with improved recovery behavior versus prior MDmesh generations.

Key Specifications

Pinout & Package

STU4N52K3 uses the IPAK (TO-251) single-ended leaded package with exposed drain tab (D) for thermal and electrical connection. The package features a 9.0–9.4 mm body length, 6.0–6.2 mm width, and 16.1–16.78 mm height, optimized for through-hole mounting and manual rework compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP4N52K3 and STD4N52K3, STU4N52K3 offers identical electrical specs and thermal resistance junction-to-case, but provides through-hole IPAK mounting for enhanced mechanical reliability and simplified thermal interface in mixed-technology industrial power supplies.

Availability

STU4N52K3 is available at Aetrix Electronics and suitable for AC-DC adapters, LED drivers, PFC boost converters, and industrial auxiliary power supplies requiring stable component supply across extended product lifecycles.

Supply support for STU4N52K3 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.

STU4N52K3 belongs to the MDmesh™ K3 Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline switching applications where avalanche ruggedness, low gate charge, and fast diode recovery are critical.

FAQ

What is the maximum continuous drain current for STU4N52K3 at 100 °C case temperature?

The maximum continuous drain current is 2 A at T_C = 100 °C, as specified in Table 1 of DS7026 Rev 3. This derating from 2.5 A at 25 °C reflects thermal limitations of the IPAK package under sustained high-temperature operation without forced cooling.

Does STU4N52K3 require an external gate resistor for standard 65 kHz flyback operation?

Yes - a 4.7 Ω gate resistor is used in the official test circuit (Figure 15) for resistive load switching characterization. This value balances switching speed (t_d(on) = 8 ns, t_f = 14 ns) and gate ringing suppression; values below 3.3 Ω may induce oscillation due to low gate impedance and layout parasitics.

How does the Zener-protected gate affect PCB layout requirements?

The integrated ±30 V gate-source Zener eliminates the need for discrete 12–15 V Zener clamps. Layout must still minimize gate loop inductance (<10 nH) and avoid routing gate traces near noisy drain nodes to prevent coupling-induced false turn-on, as the Zener only clamps overvoltage, not noise transients.

Can STU4N52K3 replace STP4N52K3 in an existing TO-220 footprint?

No - STU4N52K3 uses IPAK (TO-251), which has different lead spacing, body dimensions, and mounting hole pattern than TO-220. Direct replacement requires PCB redesign. However, both share identical die characteristics and thermal resistance junction-to-case (2.78 °C/W), enabling functional equivalence in new designs.