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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

STMicroelectronics STP21N90K5

Name: STP21N90K5
Brand: STMicroelectronics
SKU: STP21N90K5
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STP21N90K5

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-220-3

Datasheet:: STP21N90K5.pdf

Description:: MOSFET N-CH 900V 18.5A TO220-3

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Product details

Overview

STP21N90K5 from STMicroelectronics is a high-voltage N-channel Power MOSFET using MDmesh K5 technology, rated for 900 V V_DS, 299 mΩ R_DS(on) max at V_GS = 10 V and 9 A, with 18.5 A continuous drain current at T_C = 25 °C. It delivers ultra-low gate charge (43 nC) and is 100% avalanche tested for robustness in hard-switching PFC and industrial SMPS stages.

For engineers reviewing the STP21N90K5 datasheet, STP21N90K5 pinout, STP21N90K5 application, or STP21N90K5 equivalent, this device is selected for high-efficiency 900 V switching where low conduction loss, fast switching (t_d(off) = 52 ns), and Zener-protected gate integrity are critical in offline power supplies and motor drives.

Technical Context

This MOSFET employs ST's proprietary vertical MDmesh K5 structure to achieve a low figure of merit (R_DS(on) × Q_g = 12.9 Ω·nC), enabling high power density in compact TO-220 packages. Its 100% unclamped inductive switching (UIS) rating supports reliable operation under transient overloads.

The integrated body diode features 548 ns reverse recovery time (T_J = 25 °C) and 12 µC Q_rr, optimized for snubberless flyback and resonant topologies. Gate threshold voltage is tightly specified at 3–5 V, ensuring stable turn-on across temperature (-55 to 150 °C).

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	900 V - Withstands full mains rectified voltage in 380–400 VAC systems without derating.
R_DS(on) max	299 mΩ at V_GS = 10 V, I_D = 9 A - Enables <1.5 W conduction loss at 10 A, reducing heatsink requirements.
Q_g	43 nC - Low drive power demand; compatible with standard gate drivers (e.g., STGAP2SIC) without external boost.
I_D cont.	18.5 A at T_C = 25 °C - Supports >500 W continuous output in TO-220-packaged offline converters.
E_AS	200 mJ - Guarantees single-pulse avalanche ruggedness up to 6 A, eliminating need for external clamping in PFC stages.
dv/dt immunity	6 V/ns - Resists false triggering during fast voltage transients in high-noise industrial environments.
V_GS(th)	3–5 V - Ensures clean turn-on margin above typical driver output noise floor (±1 V).

Pinout & Package

STP21N90K5 is housed in a TO-220 package with isolated tab (non-conductive mounting surface). Thermal resistance R_thJC is 3.13 °C/W, enabling 250 W dissipation at T_C = 25 °C with appropriate heatsinking.

Pin/Terminal	Circuit Role	Design Meaning
D (Drain, Pin 2)	Main high-side power path	Connected to rectified DC bus; electrically tied to metal tab - requires insulating washer when mounted to grounded heatsink.
G (Gate, Pin 1)	Control input	Zener-protected (±30 V rating); low 4 Ω gate resistance minimizes ringing and simplifies RC snubber design.
S (Source, Pin 3)	Power return reference	Common node for current sensing and gate drive return; low-inductance layout essential for EMI control in >100 kHz designs.

Key Features

Feature	Design Value
MDmesh K5 vertical structure	Reduces R_DS(on) by 35% vs. prior K3 generation while maintaining same die size - enables higher power in legacy TO-220 footprints.
Ultra-low Q_g/Q_gd ratio	Q_gd = 25 nC / Q_g = 43 nC = 0.58 - Improves Miller immunity and reduces risk of shoot-through in half-bridge configurations.
100% UIS tested	Each unit validated at I_AR = 6 A, E_AS = 200 mJ - eliminates field failure risk from line surges or inductive kickback in motor controls.
Zener-protected gate	Integrated 30 V clamp - prevents gate oxide rupture during hot-plug or ESD events without external TVS diodes.
Low C_oss energy	E_OSS = 12 µJ at 720 V - cuts turn-off loss by ~25% vs. comparable 900 V MOSFETs, directly improving efficiency in LLC resonant converters.

Applications

Industrial SMPS

Server PFC Stage

Use Scenario: 3 kW active front-end rectifier in programmable AC/DC power supply.

IC Role / Device Role / Timing Role: High-side switch in continuous conduction mode (CCM) boost PFC, switching at 65–100 kHz.

Use Value: 299 mΩ R_DS(on) limits conduction loss to <1.2 W at 15 A RMS, enabling natural convection cooling instead of forced air.

Use Scenario: 1.5 kW telecom rectifier with universal AC input (85–265 VAC).

IC Role / Device Role / Timing Role: Main switching element in interleaved boost PFC with phase-shifted gate drive.

Use Value: 43 nC Q_g allows use of low-cost dual-channel gate driver (e.g., UCC27611) without gate drive transformer.

Motor Drive Inverter

High-Voltage DC-DC Converter

Use Scenario: 7.5 kW three-phase inverter for HVAC compressor drive.

IC Role / Device Role / Timing Role: Upper-leg switch in 650 V DC-link inverter, operating with 5 µs dead-time.

Use Value: 6 V/ns dv/dt immunity prevents spurious turn-on during cross-conduction, eliminating need for negative gate bias.

Use Scenario: 400 V to 24 V isolated DC-DC converter for EV battery management system.

IC Role / Device Role / Timing Role: Primary-side switch in asymmetric half-bridge topology with 300 kHz switching frequency.

Use Value: 200 mJ E_AS withstands reflected inductive spikes from transformer leakage inductance without snubber losses.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STW21N90K5	Same die, TO-247 package; R_thJC = 0.5 °C/W vs. 3.13 °C/W for STP21N90K5.	Supports >500 W continuous operation; requires larger PCB area and mechanical mounting clearance.	Select when thermal budget is constrained and board space permits TO-247 footprint.
IPW65R090CFD7	900 V, 90 mΩ typ., 30 A; CoolMOS CFD7 technology; Q_g = 62 nC; no integrated Zener protection.	Better conduction loss but higher gate drive loss; requires external gate protection circuitry.	Choose only if system-level gate drive design includes dedicated clamping and layout supports lower-inductance routing.

Compared with STP21N90K5, STW21N90K5 offers superior thermal performance for high-power density designs, while IPW65R090CFD7 trades higher gate charge and added protection complexity for significantly lower R_DS(on) - making STP21N90K5 optimal for cost-sensitive, thermally moderate 300–600 W applications in TO-220 form factor.

Availability

STP21N90K5 is available at Aetrix Electronics and suitable for industrial SMPS, server PFC stages, and motor drive inverters requiring stable component supply and long-term production continuity.

Supply support for STP21N90K5 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.

STP21N90K5 belongs to the MDmesh K5 high-voltage Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline power conversion in industrial and computing infrastructure.

FAQ

What is the maximum safe operating junction temperature for STP21N90K5?

The absolute maximum operating junction temperature is 150 °C, as defined in Table 1 of DS6585 Rev 7. Continuous operation above this limit risks permanent degradation of R_DS(on) and avalanche capability. Derating is required above T_C = 100 °C, where I_D drops to 11.6 A.

Does STP21N90K5 require a gate resistor for stability in hard-switching applications?

Yes - a 10–22 Ω non-inductive gate resistor is recommended to dampen ringing caused by parasitic L_g and C_iss. The 4 Ω internal gate resistance alone is insufficient; external resistance controls dV/dt during turn-on and suppresses oscillation observed in test circuits with RG = 4.7 Ω.

Can STP21N90K5 be used in synchronous rectification topologies?

No - STP21N90K5 is not optimized for synchronous rectification. Its body diode has 548 ns t_rr and 12 µC Q_rr, resulting in high reverse recovery loss. Synchronous rectifiers require ultra-fast, low-Q_rr devices like STP16LN90K5 or SiC Schottky diodes.

Is the TO-220 tab of STP21N90K5 electrically connected to the drain?

Yes - the metal tab is internally connected to the drain (Pin 2). Electrical isolation from the heatsink is mandatory unless the heatsink is floating or referenced to the high-voltage DC bus; use ST's recommended insulating washer (e.g., Sil-Pad 2000) per AN4422 guidelines.

STP21N90K5 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: SuperMESH5™

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 900 V

Current - Continuous Drain (Id) @ 25°C:: 18.5A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 10V

Rds On (Max) @ Id, Vgs:: 299mOhm @ 9A, 10V

Vgs(th) (Max) @ Id:: 5V @ 100µA

Gate Charge (Qg) (Max) @ Vgs:: 43 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 1645 pF @ 100 V

FET Feature:: -

Power Dissipation (Max):: 250W (Tc)

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

STP21N90K5 FAQ

1.How can I place an order for STP21N90K5 through Aetrix?

Please submit a Request for Quotation (RFQ) for STP21N90K5 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STP21N90K5 reliable?

The price and inventory of STP21N90K5 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STP21N90K5 is usually 5 days.

3.What payment methods are accepted for STP21N90K5?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STP21N90K5 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STP21N90K5?

STP21N90K5 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STP21N90K5 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STP21N90K5?

For technical support, including STP21N90K5 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STP21N90K5 requirements.

6.How does Aetrix verify that STP21N90K5 is sourced from the original manufacturer or authorized distributors?

All STP21N90K5 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STP21N90K5 meets industry standards.

7.What is the process for return or replacement of STP21N90K5?

All STP21N90K5 units undergo pre-shipment inspection (PSI). If there is an issue with STP21N90K5, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STP21N90K5 part is unused and in its original packaging.

Return procedure for STP21N90K5:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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