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
What are the key features of STF21N65M5(045Y)?
- 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
What is STF21N65M5(045Y) used for?
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.
What are the specifications of STF21N65M5(045Y)?
| YTEOL | 0 |
| Package | Transistor Outline, Vertical |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| Country of Origin | Mainland China |
Where can I find the STF21N65M5(045Y) datasheet?
STF21N65M5(045Y) Datasheet DownloadOfficial datasheet from STMicroelectronics
What are equivalent replacements for STF21N65M5(045Y)?
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.
Related Guides
CSD87313DMS Synchronous Buck Power Stage Design Guide
Design a compact CSD87313DMS synchronous buck stage with practical guidance for loss, gate drive, PCB layout, EMI, thermal validation, and sourcing.
Aug 6, 2026
STEF05SGR eFuse Selection Guide for 5 V Overcurrent Protection
Choose STEF05SGR for 5 V overcurrent protection by checking current-limit margin, inrush, thermal loss, fault response, and sourcing.
Aug 6, 2026
C0402C103K3RACTU Selection Guide: Choosing a 10 nF 0402 MLCC
Select C0402C103K3RACTU by voltage margin, X7R behavior, tolerance, 0402 assembly risk, and qualified alternatives.
Aug 4, 2026
STM32H753VIT6 MCU Selection Guide: Memory, Package, Connectivity, and Security
Choose STM32H753VIT6 by evaluating memory architecture, LQFP-100 pin fit, connectivity, security, power, and sourcing tradeoffs.
Aug 4, 2026
Why Buy from FindMyChip
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.
In Stock · 24h Response · Worldwide Shipping
Response within 24 hours · Worldwide shipping
“Their engineering team helped us find a pin-compatible alternative when our original MCU went EOL.”
You May Also Like
AO3416
Alpha & Omega Semiconductors
MOSFET (N-Channel)
2SK3568
Toshiba
MOSFET (N-Channel)
BSS139 H6327
Infineon
MOSFET (N-Channel)
TPWR8004PL,L1Q
Toshiba
MOSFET (N-Channel)
TPW1R005PL,L1Q
Toshiba
MOSFET (N-Channel)
ZXMN3B01FTA
Diodes Inc.
MOSFET (N-Channel)
AO3422
Alpha & Omega Semiconductors
MOSFET (N-Channel)
SI4204DY-T1-GE3
Vishay
MOSFET (N-Channel)
IRLML2402TRPBF
Infineon
MOSFET (N-Channel)
IRLML2803TRPBF
Infineon
MOSFET (N-Channel)
IRF7607TRPBF
Infineon
MOSFET (N-Channel)
IPD530N15N3GATMA1
Infineon
MOSFET (N-Channel)
BSZ520N15NS3GATMA1
Infineon
MOSFET (N-Channel)
BSC360N15NS3GATMA1
Infineon
MOSFET (N-Channel)
SQ3426AEEV-T1_GE3
Vishay
MOSFET (N-Channel)
IPI041N12N3 G
Infineon
MOSFET (N-Channel)
PMZB290UNE2
Nexperia
MOSFET (N-Channel)
ZVN4306GVTA
Diodes Inc.
MOSFET (N-Channel)
SIA459EDJ-T1-GE3
Vishay
MOSFET (N-Channel)
NTR3C21NZT1G
ON Semiconductor
MOSFET (N-Channel)
TN2404K-T1-E3
Vishay
MOSFET (N-Channel)
SI2312CDS-T1-GE3
Vishay
MOSFET (N-Channel)
DMN2230UQ-7
Diodes Inc.
MOSFET (N-Channel)
CPH6442-TL-W
ON Semiconductor
MOSFET (N-Channel)