Toshiba Semiconductor and Storage TK7A55D(STA4,Q,M)

Overview

TK7A55D(STA4,Q,M) from Toshiba is a silicon N-channel power MOSFET in the π-MOSⅦ family, designed for high-voltage switching regulator applications. It features 550 V drain-source breakdown voltage (V_(BR)DSS), 1.0 Ω typical R_DS(ON) at V_GS = 10 V and I_D = 3.5 A, 3.6 S typical forward transfer admittance (|Y_fs|), and 162 mJ single-pulse avalanche energy - enabling robust operation in offline SMPS primary-side switches.

For engineers reviewing the TK7A55D(STA4,Q,M) datasheet, TK7A55D(STA4,Q,M) pinout, TK7A55D(STA4,Q,M) application, or TK7A55D(STA4,Q,M) equivalent, key selection considerations include its 550 V rating, 7 A continuous drain current capability, SC-67 package thermal performance (R_th(ch-c) = 3.57 °C/W), and verified avalanche ruggedness under repetitive and single-pulse conditions.

Technical Context

This MOSFET employs a planar vertical structure optimized for high-voltage hard-switching topologies. Its enhancement-mode gate threshold (V_th = 2.4–4.4 V) ensures reliable turn-on with standard 10 V gate drive, while low Crss (4 pF) and Q_gd (6 nC) support fast, low-loss switching in flyback and forward converters operating up to several hundred kHz.

The integrated body diode exhibits V_DSF = −1.7 V at I_DR = 7 A and t_rr = 1200 ns, making it suitable for discontinuous conduction mode (DCM) operation where diode recovery behavior impacts efficiency and EMI. Thermal design must respect T_ch ≤ 150 °C, enforced via case temperature monitoring due to R_th(ch-a) = 62.5 °C/W in still air.

Key Specifications

Pinout & Package

TK7A55D(STA4,Q,M) is housed in the SC-67 (Toshiba 2-10U1B) through-hole package - a thermally enhanced variant of TO-220AB with isolated tab, rated for 150 °C channel temperature and weighing 1.7 g. The package features standardized lead spacing (2.54 mm pitch), 15.0 mm length, and 13 mm width, with leads formed for PCB mounting and mechanical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP7NK50ZFP and IXTP50N10P, TK7A55D(STA4,Q,M) uniquely combines 550 V rating, certified avalanche energy, and SC-67 thermal performance - making it the sole option among the three qualified for primary-side switching in universal-input, high-reliability industrial SMPS.

Availability

TK7A55D(STA4,Q,M) is available at Aetrix Electronics and suitable for AC-DC adapters, industrial PLC power supplies, and offline LED drivers requiring stable component supply across extended product lifecycles.

Supply support for TK7A55D(STA4,Q,M) 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 decades of expertise in high-reliability discrete components.

The π-MOSⅦ series - including TK7A55D(STA4,Q,M) - was engineered specifically for high-efficiency, high-voltage switching regulators in industrial and consumer power supplies, emphasizing avalanche ruggedness and thermal stability.

FAQ

What is the maximum continuous drain current for TK7A55D(STA4,Q,M) at 25°C case temperature?

The TK7A55D(STA4,Q,M) supports a maximum continuous drain current (I_D) of 7 A at T_c = 25°C, as specified in its Absolute Maximum Ratings table. This rating assumes proper heatsinking to maintain case temperature at or below 25°C; derating is required above this temperature per the PD–Tc curve, with full derating to zero at 150°C channel temperature.

Does TK7A55D(STA4,Q,M) have a specified avalanche energy rating, and under what test conditions?

Yes, TK7A55D(STA4,Q,M) has a single-pulse avalanche energy rating of 162 mJ, measured under the conditions: V_DD = 90 V, initial channel temperature T_ch = 25°C, inductance L = 4.23 mH, gate resistance R_G = 25 Ω, and avalanche current I_AR = 7 A. Repetitive avalanche energy is rated at 3.5 mJ per pulse, limited by channel temperature rise.

What is the gate threshold voltage range for TK7A55D(STA4,Q,M), and how does it affect drive circuit design?

The gate threshold voltage (V_th) for TK7A55D(STA4,Q,M) is specified from 2.4 V to 4.4 V at V_DS = 10 V and I_D = 1 mA. This range confirms enhancement-mode operation and indicates that a minimum gate drive of 5 V is required for reliable turn-on, while 10 V is recommended to achieve the specified 1.0 Ω R_DS(ON). Drive circuits must ensure sufficient voltage margin above V_th(max) to avoid partial turn-on and thermal runaway.

Is TK7A55D(STA4,Q,M) suitable for use in synchronous rectification topologies?

No, TK7A55D(STA4,Q,M) is not optimized for synchronous rectification. Its body diode has relatively slow reverse recovery (t_rr = 1200 ns) and high forward voltage (V_DSF = −1.7 V at 7 A), resulting in significant conduction and switching losses in secondary-side positions. It is designed for primary-side switching where diode performance is less critical; dedicated low-V_F, fast-t_rr MOSFETs should be used for SR stages.

What package type does TK7A55D(STA4,Q,M) use, and how does it differ from standard TO-220AB?

TK7A55D(STA4,Q,M) uses the SC-67 package (Toshiba designation 2-10U1B), which is a variant of TO-220AB with an electrically isolated metal tab and optimized thermal path. Unlike standard TO-220AB, SC-67 provides creepage/clearance compliance for high-voltage isolation and achieves R_th(ch-c) = 3.57 °C/W - significantly better than typical TO-220AB (≈4.0–5.0 °C/W) - due to improved internal die attach and leadframe design.