STF21N65M5(045Y) STMicroelectronics MOSFET (N-Channel) (Transistor Outline, Vertical) In Stock
STMicroelectronics STF21N65M5 is an N-channel MDmesh V superjunction power MOSFET rated at 650 V and 17 A with a 150 mΩ typical RDS(on) in a TO-220FP narrow-lead package. It delivers fast switching and low gate charge optimized for LLC resonant converters and PFC stages. Available from authorized distributors with worldwide shipping.
- Manufacturer
- STMicroelectronics
- Package
- Transistor Outline, Vertical
- Pin Count
- 3
- Lifecycle
- OBSOLETE
- Datasheet
- STF21N65M5(045Y) Datasheet PDF
- Category
- MOSFET (N-Channel)
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 650 V MDmesh V superjunction technology achieves 150 mΩ typical RDS(on) at 17 A, delivering best-in-class figure-of-merit for AC-DC power conversion
- Optimized gate charge and output capacitance enable low switching losses in LLC resonant converter and active PFC topologies operating above 100 kHz
- TO-220FP narrow-lead package provides galvanic creepage isolation between gate/source pins and drain tab, critical for safety-isolated power supply designs
Applications
The STF21N65M5 is designed for high-voltage AC-DC power conversion applications including offline flyback converters, LLC resonant topologies, and active power factor correction (PFC) stages in the 100 W to 500 W range. Its 650 V rating with MDmesh V superjunction structure supports universal input (85 V to 265 V AC) designs used in server PSUs, industrial power supplies, and lighting ballasts. The narrow-lead TO-220FP package suits PCB layouts requiring creepage isolation in safety-certified consumer and industrial equipment.
Specifications
| YTEOL | 0 |
| Package | Transistor Outline, Vertical |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| Country of Origin | Mainland China |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for STF21N65M5(045Y):
Power Field-Effect Transistor, 17A I(D), 650V, 0.19ohm, 1-Element, N-Channel, Silicon, Metal-oxide Semiconductor FET, TO-220AB
Frequently Asked Questions
What voltage and current ratings does the STF21N65M5 offer and which converter topologies benefit most?
The STF21N65M5 is rated for 650 V drain-source voltage and 17 A continuous drain current with a typical RDS(on) of 150 mΩ at 10 V gate bias. These parameters suit it for primary-side switching in offline LLC resonant converters, half-bridge topologies, and PFC boost stages operating from rectified universal AC input (85 V to 265 V AC) in the 100 W to 500 W power range.
How does the MDmesh V superjunction structure in the STF21N65M5 improve switching efficiency compared to standard planar MOSFETs?
The MDmesh V superjunction technology achieves a charge-balanced drift region that simultaneously lowers both RDS(on) and output capacitance (Coss), breaking the classical silicon trade-off. At 650 V, the STF21N65M5 provides a specific RDS(on) figure-of-merit roughly 2-4x better than equivalent planar MOSFETs, directly reducing conduction and switching losses in resonant converters operating above 100 kHz switching frequency.
Why does the STF21N65M5 use a TO-220FP narrow-lead package rather than a standard TO-220 for isolated power supply designs?
The TO-220FP narrow-lead package increases the creepage and clearance distance between the gate/source pins and the drain tab (heatsink), meeting the 6 mm to 8 mm isolation requirements of IEC 60950 and IEC 62368 for primary-to-secondary safety separation. Standard TO-220 packages have shorter lead spans that can fall short of creepage requirements in 650 V offline designs without additional insulation measures.
How does the STF21N65M5 compare to a 600 V MOSFET for a 400 V DC bus PFC stage?
A 600 V MOSFET provides only 50 V of headroom above the 400 V PFC output bus, which is insufficient when input line voltage peaks and transients push the rail toward 430 V. The STF21N65M5's 650 V rating provides a safe 250 V derating margin above the nominal 400 V bus, while its 150 mΩ RDS(on) remains competitive with 600 V superjunction devices, making it the preferred choice for reliable, safety-margined PFC designs.
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About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
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