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

STMicroelectronics STD55NH2LLT4

Name: STD55NH2LLT4
Brand: STMicroelectronics
SKU: STD55NH2LLT4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STD55NH2LLT4

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: STD55NH2LLT4.pdf

Description:: MOSFET N-CH 24V 40A DPAK

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Inventory:5,005

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Product details

Overview

STD55NH2LLT4 from STMicroelectronics is an N-channel 24V, 40A DPAK Power MOSFET featuring ultra-low R_DS(on) (0.010 Ω @ V_GS = 10V), low gate charge (8.7 nC), and optimized for high-frequency synchronous buck converters as a high-side switch. It leverages STripFET™ technology to minimize conduction and switching losses in telecom and computing power supplies.

For engineers reviewing the STD55NH2LLT4 datasheet, STD55NH2LLT4 pinout, STD55NH2LLT4 application, or STD55NH2LLT4 equivalent, key selection criteria include gate threshold voltage (1 V), thermal resistance (2.5 °C/W junction-to-case), avalanche energy rating (600 mJ), and DPAK package compatibility with high-density PCB layouts.

Technical Context

This MOSFET is engineered for high-side switching in synchronous DC-DC converters, where fast turn-on/turn-off dynamics (t_d(on) = 15 ns, t_f = 10 ns) and low Q_gd/Q_gs ratio reduce cross-conduction risk. Its 24V V_DSS rating and 1 V V_GS(th) support logic-level drive in 3.3V/5V control systems.

The device exhibits low output capacitance (C_oss = 385 pF @ 25V) and minimal reverse recovery charge (Q_rr = 28 nC), enabling efficient operation in hard-switched topologies up to several hundred kHz. Its R_DS(on) × Q_g product sets an industry benchmark for power loss optimization.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	24 V - Maximum drain-source blocking voltage; defines safe operating range in 24V bus applications
R_DS(on)	0.010 Ω @ V_GS = 10V - Enables ≤4 W conduction loss at 20A, critical for thermal management in compact converters
Q_g	8.7 nC - Low total gate charge reduces driver power demand and enables <100 ns switching transitions
I_D (continuous)	40 A @ T_C = 25°C - Sustains high current in short-duration peak loads typical in server VRMs
E_AS	600 mJ - Robust unclamped inductive switching capability supports reliable operation during load transients
R_thj-case	2.5 °C/W - Enables direct heatsinking to PCB copper or external heatsink without thermal derating below 60W
V_GS(th)	1 V - Ensures full enhancement with standard logic-level gate drivers (e.g., 3.3V microcontroller outputs)

Pinout & Package

DPAK (TO-252) package: surface-mount, single-drain-tab configuration with exposed drain pad for thermal and electrical connection.

Pin/Terminal	Circuit Role	Design Meaning
1 (Gate)	Control terminal	Accepts logic-level input; low input capacitance (C_iss = 990 pF) minimizes driver loading
2 (Source)	Reference node	Common return path for load current; tied to ground or low-side switch source in half-bridge
3 (Drain)	Power output	Connected to high-voltage rail; large copper tab provides low-inductance, high-current path and thermal conduction

Key Features

Feature	Design Value
Ultra-low R_DS(on) × Q_g	Industry benchmark for minimizing combined conduction + gate drive losses in high-frequency SMPS
Low threshold voltage	1 V V_GS(th) ensures reliable turn-on with 3.3V/5V controllers without level-shifting circuitry
Optimized for high-side use	Low Q_gd/Q_gs ratio and fast t_f (10 ns) suppress shoot-through in synchronous buck topologies
Robust avalanche rating	600 mJ single-pulse E_AS allows safe operation under inductive switching stress without snubbers
ECOPACK® compliant	Lead-free second-level interconnect meets RoHS and JEDEC JESD97 environmental requirements

Applications

Telecom DC-DC Converters

Server Voltage Regulator Modules (VRMs)

Use Scenario: Point-of-load conversion in 48V-to-12V intermediate bus architectures for base station RF power amplifiers.

IC Role / Device Role / Timing Role: High-side switch in synchronous buck stage operating at 300–500 kHz with tight duty-cycle control.

Use Value: 0.010 Ω R_DS(on) limits conduction loss to <4 W at 20A, enabling >94% efficiency at full load without forced air cooling.

Use Scenario: Core power delivery for multi-core CPUs in rack-mounted servers requiring rapid transient response.

IC Role / Device Role / Timing Role: High-side FET in multiphase buck converter with phase interleaving up to 1 MHz per phase.

Use Value: 8.7 nC Q_g and 10 ns t_f allow precise dead-time control and minimize overlap losses across 4–8 phases.

Industrial PLC Power Supplies

Networking Switch Fabric Power

Use Scenario: 24V auxiliary supply generation in programmable logic controllers with wide ambient temperature range (-40°C to +85°C).

IC Role / Device Role / Timing Role: Primary switching element in isolated flyback or non-isolated buck converter powering I/O modules.

Use Value: Stable R_DS(on) over temperature (±20% from -40°C to 125°C) maintains consistent efficiency across industrial environments.

Use Scenario: Mid-rail power conversion (e.g., 12V → 3.3V) for packet forwarding ASICs and SerDes interfaces in enterprise switches.

IC Role / Device Role / Timing Role: High-efficiency, low-noise high-side switch in compact, high-density POL regulators.

Use Value: Low C_oss (385 pF) and Q_rr (28 nC) reduce EMI and diode-recovery-related losses during fast load steps.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF7470PBF	R_DS(on) = 0.012 Ω @ 10V; Q_g = 11.5 nC; V_DSS = 30V	Slightly higher gate charge increases driver loss; wider V_DSS margin suits 28V systems	Select when higher voltage headroom is required and gate drive capability permits extra 3 nC charge
STL55DN6LH-1	R_DS(on) = 0.0095 Ω @ 4.5V; Q_g = 12.5 nC; DFN5x6 package, no exposed drain tab	Lower threshold enables 3.3V-only drive but lacks DPAK's thermal mass and solderability robustness	Prefer for space-constrained designs where PCB thermal vias can replace DPAK's copper tab performance

Compared with IRF7470PBF and STL55DN6LH-1, STD55NH2LLT4 delivers the lowest R_DS(on) × Q_g product in DPAK, making it optimal for thermally constrained, high-frequency telecom and server power stages where gate drive efficiency and thermal reliability are prioritized over maximum voltage rating or footprint size.

Availability

STD55NH2LLT4 is available at Aetrix Electronics and suitable for telecom DC-DC converters, server VRMs, and industrial PLC power supplies requiring stable component supply and long-term design-in support.

Supply support for STD55NH2LLT4 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

STD55NH2LLT4 belongs to ST's STripFET™ Power MOSFET product line, developed specifically for high-efficiency, high-frequency switching power conversion in space- and thermally-constrained infrastructure equipment.

FAQ

What is the maximum continuous drain current for STD55NH2LLT4 at 100°C case temperature?

The maximum continuous drain current is 28 A at T_C = 100°C, as specified in Table 1 of the datasheet. This derating reflects thermal limitations of the DPAK package and must be applied when ambient or board-level thermal conditions prevent maintaining T_C ≤ 25°C. Junction temperature remains within 175°C limit under this condition.

Does STD55NH2LLT4 have integrated gate protection?

No, STD55NH2LLT4 does not include integrated gate protection diodes or Zener clamps. External gate resistors (e.g., 4.7 Ω recommended in datasheet Figure 13) and TVS diodes are required to limit V_GS to ±16 V and suppress ringing-induced overshoot during fast switching.

Can STD55NH2LLT4 be used in synchronous rectification configurations?

No - STD55NH2LLT4 is optimized as a high-side switch, not a low-side synchronous rectifier. Its body diode reverse recovery charge (Q_rr = 28 nC) and forward voltage (V_SD = 1.3 V @ 20A) are higher than dedicated low-side FETs, increasing conduction and recovery losses in freewheeling paths.

Is STD55NH2LLT4 suitable for automotive applications?

No - STD55NH2LLT4 is not qualified to AEC-Q101 and lacks automotive-grade screening, temperature range extension (−40°C to +150°C), or failure-in-time (FIT) data. It is intended for industrial and computing applications only, per ST's official product classification and datasheet disclaimers.

STD55NH2LLT4 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: STripFET™

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 24 V

Current - Continuous Drain (Id) @ 25°C:: 40A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 4.5V, 10V

Rds On (Max) @ Id, Vgs:: 11mOhm @ 20A, 10V

Vgs(th) (Max) @ Id:: 1V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 11 nC @ 4.5 V

Vgs (Max):: ±16V

Input Capacitance (Ciss) (Max) @ Vds:: 990 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 60W (Tc)

Operating Temperature:: -55°C ~ 175°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

STD55NH2LLT4 FAQ

1.How can I place an order for STD55NH2LLT4 through Aetrix?

Please submit a Request for Quotation (RFQ) for STD55NH2LLT4 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 STD55NH2LLT4 reliable?

The price and inventory of STD55NH2LLT4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STD55NH2LLT4 is usually 5 days.

3.What payment methods are accepted for STD55NH2LLT4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STD55NH2LLT4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STD55NH2LLT4?

STD55NH2LLT4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STD55NH2LLT4 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 STD55NH2LLT4?

For technical support, including STD55NH2LLT4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STD55NH2LLT4 requirements.

6.How does Aetrix verify that STD55NH2LLT4 is sourced from the original manufacturer or authorized distributors?

All STD55NH2LLT4 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 STD55NH2LLT4 meets industry standards.

7.What is the process for return or replacement of STD55NH2LLT4?

All STD55NH2LLT4 units undergo pre-shipment inspection (PSI). If there is an issue with STD55NH2LLT4, 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 STD55NH2LLT4 part is unused and in its original packaging.

Return procedure for STD55NH2LLT4:

1.Submit a request within 90 days.

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

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