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

Toshiba Semiconductor and Storage TK4P55D(T6RSS-Q)

Name: TK4P55D(T6RSS-Q)
Brand: Toshiba Semiconductor and Storage
SKU: TK4P55D(T6RSS-Q)
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TK4P55D(T6RSS-Q)

Manufacturer:: Toshiba Semiconductor and Storage

Category:: FETs, MOSFETs

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

Datasheet:: TK4P55D(T6RSS-Q).pdf

Description:: MOSFET N-CH 550V 4A DPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

TK4P55D(T6RSS-Q) from Toshiba is a silicon N-channel power MOSFET designed for high-voltage switching in offline AC-DC converters and DC-DC regulators, featuring 550 V V_DSS, 1.5 Ω R_DS(ON) (typ.), 4 A I_D (DC), DPAK (TO-252) package, and enhancement-mode operation with V_th = 2.4–4.4 V.

For engineers reviewing the TK4P55D(T6RSS-Q) datasheet, TK4P55D(T6RSS-Q) pinout, TK4P55D(T6RSS-Q) application, or TK4P55D(T6RSS-Q) equivalent, key selection criteria include avalanche ruggedness (E_AS = 139 mJ), low gate charge (Q_g = 11 nC typ.), thermal resistance (R_th(ch-c) = 1.56 °C/W), and suitability for flyback and forward converter primary-side switches.

Technical Context

This N-channel enhancement-mode MOSFET operates as a unidirectional voltage-controlled switch in high-side configurations of isolated switching power supplies. Its 550 V breakdown rating supports universal-input (85–265 V_AC) offline applications, while its 1.5 Ω on-resistance at V_GS = 10 V enables efficient conduction at 2 A drain current.

The device integrates a built-in body diode with reverse recovery time t_rr = 900 ns (typ.) and Q_rr = 5 µC (typ.), supporting quasi-resonant and hard-switched topologies. Gate drive requirements are defined by Q_gs = 6 nC and Q_gd = 5 nC, enabling fast turn-on/turn-off with moderate gate resistor values (e.g., R_G = 50 Ω).

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	550 V - Supports full-wave rectified input up to 385 V_DC; suitable for universal-input offline SMPS without snubber oversizing.
R_DS(ON)	1.5 Ω (typ.) at V_GS = 10 V, I_D = 2 A - Limits conduction loss to ≤6 W at 4 A peak in continuous conduction mode.
I_D (DC)	4 A - Enables use in 30–50 W flyback designs with adequate heatsinking on PCB copper pour.
E_AS	139 mJ - Withstands single-pulse inductive energy during overcurrent or startup without failure; validated at V_DD = 90 V, I_AR = 4 A.
Q_g	11 nC (typ.) - Reduces gate drive power loss and allows use with standard PWM controllers (e.g., UC384x) without external buffer.
R_th(ch-c)	1.56 °C/W - Requires ≥25 cm² 2-oz copper pad for T_ch ≤150 °C at 80 W P_D (T_c = 25 °C).
t_r/t_f	18 ns / 8 ns - Enables switching frequencies up to 150 kHz with minimal overlap loss in hard-switched converters.

Pinout & Package

DPAK (TO-252) surface-mount package with exposed drain tab for thermal conduction to PCB copper. Standard JEDEC-compliant footprint (2-7K1S), 0.36 g typical weight.

Pin/Terminal	Circuit Role	Design Meaning
1: Gate	Control electrode	Receives voltage-controlled signal (2.4–4.4 V threshold); requires ESD-safe handling and <100 pF gate loop inductance for stable switching.
2: Drain (Heatsink)	High-voltage output terminal	Connected to transformer primary or bus rail; electrically and thermally tied to large copper area for heat dissipation and EMI reduction.
3: Source	Reference node / return path	Serves as local ground reference for gate drive; must be routed with low inductance to minimize ringing during dV/dt transitions.

Key Features

Feature	Design Value
Low R_DS(ON)	1.5 Ω typ. reduces I²R conduction losses in 25–50 W offline adapters, improving efficiency by ~0.8% at full load vs. 2.2 Ω alternatives.
High \|Y_fs\|	2.0 S typ. provides strong transconductance for stable gain in current-sense amplifier interfaces and fast current limiting response.
Low I_DSS	10 µA max. at 550 V ensures negligible standby leakage in high-impedance bias networks of auxiliary supplies.
Avalanche-rated	Guaranteed 139 mJ single-pulse E_AS enables robust operation under transformer saturation or output short-circuit conditions without external clamping.
Enhancement-mode V_th	2.4–4.4 V range ensures reliable turn-off at 0 V gate drive and compatibility with 5 V or 12 V logic-level controllers without level-shifting.

Applications

AC-DC Flyback Converters	DC-DC Forward Converters
Use Scenario: Primary-side switch in 24–48 W universal-input (85–265 V_AC) wall adapters and industrial power supplies. IC Role / Device Role / Timing Role: High-voltage switching element controlling energy transfer via transformer primary winding; synchronized to PWM controller frequency (65–130 kHz). Use Value: 550 V V_DSS and 139 mJ E_AS eliminate need for external RCD clamp in most designs, reducing BOM count and board space.	Use Scenario: Main switch in 50–100 W telecom and server auxiliary supplies using discrete forward topology. IC Role / Device Role / Timing Role: Unidirectional power switch conducting during PWM high-time; body diode blocks reverse current during reset phase. Use Value: Low Q_g (11 nC) and fast t_r/t_f (18/8 ns) minimize switching loss at 200 kHz, enabling >88% efficiency at full load.
LED Driver Power Stages	Industrial Motor Control Inputs
Use Scenario: High-side switch in constant-current LED drivers for street lighting and commercial fixtures operating from 277 V_AC mains. IC Role / Device Role / Timing Role: Regulates average LED current via duty-cycle-modulated switching; withstands line surges up to 4 kV per IEC 61000-4-5. Use Value: 1.5 Ω R_DS(ON) limits thermal rise in sealed enclosures; R_th(ch-a) = 125 °C/W allows natural convection cooling with minimal heatsink.	Use Scenario: Input stage switch in 24 V DC-powered PLC I/O modules and sensor interface cards requiring surge immunity. IC Role / Device Role / Timing Role: Isolates downstream circuitry from field wiring faults; activated only during valid command windows. Use Value: 4 A I_D rating supports 2 A continuous load with 2× safety margin; low IDSS (≤10 µA) prevents false triggering in high-impedance input circuits.

AC-DC Flyback Converters

DC-DC Forward Converters

Use Scenario: Primary-side switch in 24–48 W universal-input (85–265 V_AC) wall adapters and industrial power supplies.

IC Role / Device Role / Timing Role: High-voltage switching element controlling energy transfer via transformer primary winding; synchronized to PWM controller frequency (65–130 kHz).

Use Value: 550 V V_DSS and 139 mJ E_AS eliminate need for external RCD clamp in most designs, reducing BOM count and board space.

Use Scenario: Main switch in 50–100 W telecom and server auxiliary supplies using discrete forward topology.

IC Role / Device Role / Timing Role: Unidirectional power switch conducting during PWM high-time; body diode blocks reverse current during reset phase.

Use Value: Low Q_g (11 nC) and fast t_r/t_f (18/8 ns) minimize switching loss at 200 kHz, enabling >88% efficiency at full load.

LED Driver Power Stages

Industrial Motor Control Inputs

Use Scenario: High-side switch in constant-current LED drivers for street lighting and commercial fixtures operating from 277 V_AC mains.

IC Role / Device Role / Timing Role: Regulates average LED current via duty-cycle-modulated switching; withstands line surges up to 4 kV per IEC 61000-4-5.

Use Value: 1.5 Ω R_DS(ON) limits thermal rise in sealed enclosures; R_th(ch-a) = 125 °C/W allows natural convection cooling with minimal heatsink.

Use Scenario: Input stage switch in 24 V DC-powered PLC I/O modules and sensor interface cards requiring surge immunity.

IC Role / Device Role / Timing Role: Isolates downstream circuitry from field wiring faults; activated only during valid command windows.

Use Value: 4 A I_D rating supports 2 A continuous load with 2× safety margin; low IDSS (≤10 µA) prevents false triggering in high-impedance input circuits.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP4NK50ZFP	500 V V_DSS, 2.4 Ω R_DS(ON), Zener-protected gate, TO-220FP package	Lower voltage rating limits use to 230 V_AC-only designs; through-hole mounting increases assembly cost vs. DPAK.	Choose when gate protection against overvoltage transients is prioritized over voltage headroom and surface-mount assembly.
IRFBC40APBF	600 V V_DSS, 1.8 Ω R_DS(ON), TO-220 package, no guaranteed E_AS spec	Higher voltage margin but higher conduction loss; lacks specified avalanche energy, requiring external clamping in fault conditions.	Choose when absolute maximum V_DSS margin is critical and thermal design accommodates higher R_DS(ON).

Compared with STP4NK50ZFP and IRFBC40APBF, TK4P55D(T6RSS-Q) delivers optimal balance of 550 V rating, 1.5 Ω on-resistance, and guaranteed 139 mJ avalanche capability in a compact DPAK package-enabling smaller, more robust, and lower-cost offline power stages without compromising reliability.

Availability

TK4P55D(T6RSS-Q) is available at Aetrix Electronics and suitable for AC-DC flyback converters, DC-DC forward converters, and industrial LED driver power stages requiring stable component supply across production lifecycles.

Supply support for TK4P55D(T6RSS-Q) 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

Toshiba Electronic Devices & Storage Corporation is a Japanese semiconductor manufacturer specializing in power devices, logic ICs, and memory solutions, with global distribution and automotive-grade qualification capabilities.

TK4P55D(T6RSS-Q) belongs to Toshiba's π-MOS™ II family of high-voltage N-channel MOSFETs, engineered specifically for energy-efficient, space-constrained offline power conversion in consumer, industrial, and lighting applications.

FAQ

What is the maximum continuous drain current rating for TK4P55D(T6RSS-Q) at case temperature 25 °C?

The TK4P55D(T6RSS-Q) has a maximum continuous drain current I_D of 4 A at T_c = 25 °C, as specified in the Absolute Maximum Ratings table. This rating assumes proper PCB thermal management (≥25 cm² 2-oz copper) to maintain channel temperature ≤150 °C. At higher case temperatures, derating is required per the PD–Tc curve (Fig. 8.11).

Does TK4P55D(T6RSS-Q) have a specified avalanche energy rating, and how is it tested?

Yes, TK4P55D(T6RSS-Q) specifies a single-pulse avalanche energy E_AS of 139 mJ (typ.). It is tested under controlled conditions: V_DD = 90 V, T_ch = 25 °C (initial), L = 15 mH, R_G = 25 Ω, and I_AR = 4 A (Note 2, Absolute Maximum Ratings). This rating validates ruggedness during inductive switching faults.

What is the gate threshold voltage range for TK4P55D(T6RSS-Q), and why does it matter for drive circuit design?

The gate threshold voltage V_th for TK4P55D(T6RSS-Q) is 2.4–4.4 V (V_DS = 10 V, I_D = 1 mA). This range ensures reliable turn-on with standard 5 V or 12 V gate drivers while guaranteeing turn-off at 0 V. Designers must ensure gate drive voltage exceeds 4.4 V for full enhancement and avoids marginal bias near 2.4 V to prevent linear-mode heating.

Can TK4P55D(T6RSS-Q) be used in place of a 600 V MOSFET in a 277 V AC LED driver?

TK4P55D(T6RSS-Q) is rated for 550 V V_DSS, which provides sufficient margin for 277 V_AC systems (peak ≈ 392 V) including typical line surges (IEC 61000-4-5 Level 3: 2 kV). However, for designs requiring >400 V transient margin or long-term reliability under sustained overvoltage stress, a 600 V part may be preferred. TK4P55D(T6RSS-Q) remains valid where system-level testing confirms robustness.

What thermal resistance values apply to TK4P55D(T6RSS-Q), and how do they impact PCB layout?

TK4P55D(T6RSS-Q) has R_th(ch-c) = 1.56 °C/W (max) and R_th(ch-a) = 125 °C/W (max). The low channel-to-case value means effective heat transfer relies on soldering the drain tab to ≥25 cm² of 2-oz internal/external copper. The high channel-to-ambient value confirms that forced air or heatsinking is essential for >1 W continuous dissipation in enclosed environments.

TK4P55D(T6RSS-Q) Specifications

Product attributes: Attribute value

Manufacturer:: Toshiba Semiconductor and Storage

Series:: π-MOSVII

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 550 V

Current - Continuous Drain (Id) @ 25°C:: 4A (Ta)

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

Rds On (Max) @ Id, Vgs:: 1.88Ohm @ 2A, 10V

Vgs(th) (Max) @ Id:: 4.4V @ 1mA

Gate Charge (Qg) (Max) @ Vgs:: 11 nC @ 10 V

Vgs (Max):: ±30V

Input Capacitance (Ciss) (Max) @ Vds:: 490 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 80W (Tc)

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

TK4P55D(T6RSS-Q) FAQ

1.How can I place an order for TK4P55D(T6RSS-Q) through Aetrix?

Please submit a Request for Quotation (RFQ) for TK4P55D(T6RSS-Q) 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 TK4P55D(T6RSS-Q) reliable?

The price and inventory of TK4P55D(T6RSS-Q) are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TK4P55D(T6RSS-Q) is usually 5 days.

3.What payment methods are accepted for TK4P55D(T6RSS-Q)?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TK4P55D(T6RSS-Q) transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TK4P55D(T6RSS-Q)?

TK4P55D(T6RSS-Q) orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TK4P55D(T6RSS-Q) 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 TK4P55D(T6RSS-Q)?

For technical support, including TK4P55D(T6RSS-Q) datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TK4P55D(T6RSS-Q) requirements.

6.How does Aetrix verify that TK4P55D(T6RSS-Q) is sourced from the original manufacturer or authorized distributors?

All TK4P55D(T6RSS-Q) 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 TK4P55D(T6RSS-Q) meets industry standards.

7.What is the process for return or replacement of TK4P55D(T6RSS-Q)?

All TK4P55D(T6RSS-Q) units undergo pre-shipment inspection (PSI). If there is an issue with TK4P55D(T6RSS-Q), 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 TK4P55D(T6RSS-Q) part is unused and in its original packaging.

Return procedure for TK4P55D(T6RSS-Q):

1.Submit a request within 90 days.

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

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