STMicroelectronics STW9NK70Z

Overview

STW9NK70Z from STMicroelectronics is a Zener-protected N-channel SuperMESH Power MOSFET rated for 700 V drain-source voltage, 1.2 Ω max R_DS(on), and 7.5 A continuous drain current at T_C = 25 °C. It delivers high dv/dt immunity (4.5 V/ns), 100% avalanche tested ruggedness, and gate charge minimized for fast switching in offline SMPS and AC-DC adapters.

For engineers reviewing the STW9NK70Z datasheet, STW9NK70Z pinout, STW9NK70Z application, or STW9NK70Z equivalent, key selection criteria include its TO-220FP package thermal resistance (R_thJC = 3.6 °C/W), unclamped inductive avalanche energy (E_AS = 230 mJ), Zener-protected gate, and 2.5 kV insulation withstand voltage - all critical for high-reliability industrial power conversion.

Technical Context

This device implements ST's SuperMESH process - an evolution of PowerMESH - to simultaneously reduce on-resistance and enhance dynamic robustness. Its 1.2 Ω max R_DS(on) at V_GS = 10 V and 4 A enables efficient conduction, while the 4.5 V/ns peak diode recovery dv/dt rating ensures stable operation under fast transient conditions.

The integrated Zener protection clamps gate-source voltage to ±30 V, preventing ESD-induced failure during handling or circuit transients. Its 100% avalanche testing guarantees single-pulse ruggedness up to 230 mJ at T_J = 25 °C, supporting reliable unclamped inductive switching in flyback and resonant topologies.

Key Specifications

Pinout & Package

STW9NK70Z is housed in a TO-220FP (Type B) package - a full-packaged variant with insulated backside, enabling direct heatsink mounting without additional isolation hardware. The package features 3 leads, with lead-to-heatsink insulation rated at 2.5 kV RMS for 1 s at 25 °C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP9NK70ZFP, STW9NK70Z shares identical electrical specs and package but differs in marking and order code - no design impact. Compared with IPP65R190C7, it trades lower R_DS(on) for guaranteed 700 V operation and proven avalanche ruggedness in legacy industrial designs.

Availability

STW9NK70Z is available at Aetrix Electronics and suitable for AC-DC adapters, flyback SMPS, and industrial LED drivers requiring stable component supply, long-term lifecycle support, and compliance with IEC/EN 62368-1 insulation requirements.

Supply support for STW9NK70Z 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

STW9NK70Z belongs to ST's SuperMESH Power MOSFET product line - engineered specifically for high-voltage, medium-power switching applications where avalanche ruggedness, dv/dt immunity, and Zener gate protection are mandatory.

FAQ

Is STW9NK70Z pin-compatible with STP9NK70ZFP?

Yes - both share identical TO-220FP package outline, pin assignment (G-D-S), and mechanical dimensions per DS2726 Rev 3. The devices differ only in order code and marking; electrical characteristics, thermal data, and safe operating area curves are identical across both part numbers.

What is the maximum recommended gate resistor value for hard-switching applications?

For 65–100 kHz operation with minimal switching loss, ST recommends R_G = 4.7 Ω (per Figure 13 test circuit). Values >10 Ω increase turn-off time beyond 60 ns and risk exceeding SOA limits during fast load transients; values <2.2 Ω may cause gate ringing due to PCB inductance.

Does STW9NK70Z require external gate protection in standard flyback designs?

No - the integrated Zener diode clamps V_GS to ±30 V, eliminating need for external TVS or Zener diodes in typical flyback circuits with ≤12 V gate drive. External protection remains advisable only in systems with >15 V gate drive or severe board-level ESD exposure beyond 4 kV HBM.

Can STW9NK70Z be used in synchronous rectification topologies?

No - STW9NK70Z is optimized as a primary-side high-voltage switch, not a low-V_DS synchronous rectifier. Its 1.2 Ω R_DS(on) and 700 V rating make it unsuitable for secondary-side operation where <50 V devices with <20 mΩ R_DS(on) are required for efficiency.