STW12NK95Z - 950V 10A Zener SuperMESH MOSFET | STMicroelectronics
MPN: STW12NK95Z ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.95 | $3.95 |
| 10 | $3.55 | $35.50 |
| 25 | $3.35 | $83.75 |
| 100 | $3.19 | $319.00 |
| 1,000 | $3.19 | $3,190.00 |
STW12NK95Z Overview
A Power MOSFET is a type of field-effect transistor optimized for high power and high voltage switching. It operates by controlling the conductivity between the drain and source terminals through an insulated gate voltage. Power MOSFETs are essential components in power electronics, serving as switches in power supplies, inverters, and motor drives. They belong to the broader discrete semiconductor family, alongside diodes, IGBTs, and thyristors.
Key features include Zener protection, which safeguards the gate oxide from overvoltage transients, and minimized gate charge for faster switching and reduced drive losses. The device is 100% avalanche tested, ensuring ruggedness under inductive load conditions, and offers extremely high dv/dt capability for reliable fast-switching operation.
The SuperMESH technology, an evolution of ST's strip-based PowerMESH layout, significantly reduces on-resistance while maintaining high breakdown voltage. This results in lower conduction losses and improved efficiency, while minimized gate charge enables higher frequency operation and smaller magnetic components.
Typical applications include switch-mode power supplies (SMPS), power factor correction (PFC) circuits, high-voltage DC-DC converters, and lighting systems where efficiency and reliability are critical.
When designing with this device, ensure a proper gate drive voltage (typically 10V) to fully enhance the channel and minimize conduction losses, and provide adequate heatsinking since the device can dissipate up to 230W at maintained case temperature.
Drop-in alternatives for STW12NK95Z — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STW12NK95Z (same form factor and footprint) — differing in Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STW11NK90Z
✅ Drop-In✓ In Stock
$2.7 / Unit
View Datasheet →STW11NK100Z
✅ Drop-In📋 Reference alternative (not in catalog)
STW12NK90Z
✅ Drop-In📋 Reference alternative (not in catalog)
FQH8N100C
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
IXFH10N100
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
STW12NK95Z Maximum Ratings & Electrical Characteristics
| Polarity | N-Channel |
| Drain-Source Breakdown Voltage (Vdss) | 950 V |
| Continuous Drain Current (Id) at Tc | 10 A |
| On-Resistance (Rds on) Max | 0.90 ohm |
| On-Resistance (Rds on) Typ | 0.69 ohm |
| Power Dissipation (Pd) at Tc | 230 W |
| Technology | SuperMESH (Zener-protected PowerMESH) |
| Gate Protection | Zener-protected gate oxide |
| Avalanche Rating | 100% avalanche tested |
| Mounting Type | Through Hole |
| Package | TO-247-3 |
| Operating Temperature | -55C to +150C (junction) |
STW12NK95Z Pin Configuration
| Pin 1 | Gate — Gate terminal (Zener-protected relative to source) |
| Pin 2 | Drain — Drain terminal, connected to metal tab |
| Pin 3 | Source — Source terminal, reference for gate drive |
Safe Operating Area
Typical Applications
STW12NK95Z is suitable for 6 applications: Switch-Mode Power Supplies (SMPS), Power Factor Correction (PFC), High-Voltage DC-DC Converters, Lighting Systems (HID and High-Intensity Discharge), Motor Drives and Inverters, Industrial Power Adaptors and Battery Chargers.
Switch-Mode Power Supplies (SMPS)
The STW12NK95Z suits offline SMPS primary-side switching where its 950V Vdss covers rectified 230VAC mains plus flyback leakage spikes. With 0.69 ohm typical Rds(on) and minimized gate charge, it balances conduction and switching losses at 65-150 kHz switching frequencies. The Zener-protected gate tolerates ringing transients common in flyback and forward topologies, improving field reliability.
Recommended
Power Factor Correction (PFC)
In boost-type PFC stages operating from universal or 230VAC mains, the switch sees bus voltage near 400V plus high-frequency ripple; the 950V rating of the STW12NK95Z provides generous margin. Its 10A continuous rating and 230W dissipation capability at controlled case temperature support several hundred watts of PFC throughput, while avalanche ruggedness absorbs inductor current transients during startup and load steps.
Recommended
High-Voltage DC-DC Converters
For isolated DC-DC converters fed from high-voltage DC buses (e.g., 400V industrial links), the STW12NK95Z provides the primary-side switch function. Its low 0.69 ohm typical Rds(on) limits conduction loss at 10A load currents, while minimized gate charge enables hard- or soft-switched operation with reduced drive power. The through-hole TO-247-3 package eases thermal design with bolt-on heatsinks in industrial converters.
Recommended
Lighting Systems (HID and High-Intensity Discharge)
HID lamp ballasts and high-power LED drivers running from rectified mains require switches rated above 600V. The STW12NK95Z's 950V breakdown and Zener gate protection handle ignition-pulse transients typical in discharge-lamp ignition circuits. Its 100% avalanche testing adds robustness against the inductive kick of ballast transformers, supporting reliable long-life operation in industrial and street-lighting ballast designs.
Recommended
Motor Drives and Inverters
In high-voltage DC bus motor drives and small inverter stages, the STW12NK95Z operates as a hard-switched or resonant power switch. Its extremely high dv/dt capability prevents false turn-on from bus transients, and the 10A continuous rating covers fractional-horsepower motor currents. TO-247 mounting allows direct attachment to the drive heatsink; use a Kelvin source connection and negative gate drive to improve dv/dt immunity.
Recommended
Industrial Power Adaptors and Battery Chargers
High-power adaptors and industrial battery chargers with 230VAC input need a primary switch with wide voltage margin. The STW12NK95Z's 950V rating covers input surges, and its low gate charge reduces no-load standby losses critical for efficiency regulations. The Zener gate clamp protects against transformer leakage-induced gate spikes, reducing external protection component count in cost-sensitive charger designs.
Recommended
Recommended Products Summary
Engineering reference data for STW12NK95Z — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STW11NK90Z | STW11NK100Z | STW12NK90Z | FQH8N100C | IXFH10N100 |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | onsemi | IXYS |
| Package | TO-247-3 | TO-247-3 - same | TO-247-3 - same | TO-247-3 - same | TO-247-3 - same | TO-247-3 - same |
| Vdss Breakdown Voltage | 950 V | 900 V | 1000 V | 900 V | 1000 V | 1000 V |
| Continuous Drain Current | 10 A (Tc) | 11 A | 11 A | 12 A | 8 A | 10 A |
| Gate Zener Protection | Yes | Yes | Yes | Yes | No (verify datasheet) | No (verify datasheet) |
| Technology | SuperMESH | SuperMESH | SuperMESH | SuperMESH | QFET | HEXFRET/planar |
Key Differentiators
- Higher voltage margin than 900V family members (vs STW11NK90Z)
- Lower cost than 1000V variants for adequate margin (vs STW11NK100Z)
- Higher current rating than cross-brand alternative (vs FQH8N100C)
Design Notes
At full 10A load with high Rds(on), conduction losses can reach I^2 x R of roughly 69-90W; with switching losses this approaches the 230W Tc rating only with an efficient heatsink keeping case temperature well below 150C. Size the heatsink so Tj stays under 125C with margin; use thermal grease and a calibrated TO-247 mounting screw torque per the ST datasheet mechanical section.
Keep the gate drive loop short: place the gate driver and series gate resistor close to the TO-247 gate pin, and use a Kelvin source return to minimize common-source inductance-induced false turn-on. A 5 to 22 ohm external gate resistor controls switching speed; add a 10k-20k gate-to-source pulldown resistor to prevent floating-gate turn-on during power-up.
Do not rely on the internal Zener clamp as the primary gate overvoltage protection in every design - it is a last-line protection. Ensure drain voltage ringing from transformer leakage inductance stays below 950V with snubbers or RCD clamps; repetitive avalanche beyond the rated energy degrades reliability despite the 100% avalanche test screening.
Compliance Information
Compliance status not stated in provided data; check STMicroelectronics product page for RoHS/REACH certificates.
