Toshiba Semiconductor and Storage TK7A90E,S4X

Overview

TK7A90E from Toshiba is a silicon N-channel power MOSFET in the π-MOSⅢ family, designed for high-voltage switching applications. It delivers 900 V drain-source breakdown voltage, 7 A DC drain current, and low on-resistance of 1.6 Ω (typ.) at V_GS = 10 V, enabling efficient operation in offline AC-DC converters and industrial switching regulators.

For engineers reviewing the TK7A90E datasheet, TK7A90E pinout, TK7A90E application, or TK7A90E equivalent, key selection criteria include its 900 V V_DSS, TO-220SIS package thermal performance (R_th(ch-c) = 2.78 °C/W), avalanche energy rating (E_AS = 235 mJ), and gate threshold range (2.5–4.0 V) for reliable drive compatibility with standard logic-level controllers.

Technical Context

The TK7A90E employs a planar vertical DMOS structure optimized for ruggedness and high-voltage blocking. Its enhancement-mode operation requires positive gate bias to conduct, with gate threshold defined at V_DS = 10 V and I_D = 0.7 mA - ensuring predictable turn-on behavior across temperature.

Dynamic characteristics support fast switching: typical input capacitance is 1350 pF, reverse transfer capacitance is 10 pF, and total gate charge is 32 nC (V_DD ≈ 400 V, I_D = 7 A), enabling use in hard-switched PFC and flyback topologies up to several hundred kHz.

Key Specifications

Pinout & Package

TK7A90E is housed in a TO-220SIS (JEITA SC-67, Toshiba 2-10U1S) package - a through-hole, isolated-source variant with internal creepage/clearance optimized for high-voltage safety. The package features a metal tab electrically connected to the drain, enabling direct heatsinking while maintaining isolation between source and mounting surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP9NK90ZFP and FQP9N90C, the TK7A90E offers verified avalanche ruggedness (235 mJ), tighter V_th tolerance (2.5–4.0 V), and guaranteed isolated-source packaging - making it preferable for safety-certified, surge-prone, or thermally constrained offline power stages.

Availability

TK7A90E is available at Aetrix Electronics and suitable for AC-DC power adapters, industrial motor drives, and LED street lighting drivers requiring stable component supply and long-term industrial lifecycle support.

Supply support for TK7A90E 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-voltage MOSFET design.

The TK7A90E belongs to Toshiba's π-MOSⅢ high-voltage MOSFET product line, engineered specifically for energy-efficient, compact, and reliable offline switching power supplies operating directly from rectified AC mains.

FAQ

What is the maximum continuous drain current rating for the TK7A90E?

The TK7A90E is rated for 7 A DC drain current at T_c = 25 °C. This rating assumes proper heatsinking to maintain channel temperature ≤150 °C. At elevated case temperatures, derating applies per the thermal resistance R_th(ch-c) = 2.78 °C/W - for example, at T_c = 80 °C, the usable I_D drops to approximately 4.5 A to stay within safe thermal limits. Always verify actual board-level thermal performance in final layout.

Does the TK7A90E have an isolated-source package, and why does that matter?

Yes, the TK7A90E uses the TO-220SIS package, where the source terminal is electrically isolated from the drain-connected metal tab. This isolation eliminates the need for insulating pads or washers when mounting to a common heatsink, simplifies PCB layout in high-side or half-bridge configurations, and improves safety compliance in Class I equipment. It directly impacts system-level insulation requirements and reduces assembly complexity versus standard TO-220 variants.

What is the gate threshold voltage range for the TK7A90E, and how does it affect drive circuit design?

The TK7A90E has a gate threshold voltage (V_th) range of 2.5–4.0 V, measured at V_DS = 10 V and I_D = 0.7 mA. This range ensures reliable turn-on with 5 V logic-level drivers while avoiding false triggering from noise near ground. Designers should apply ≥10 V gate drive for full enhancement (R_DS(ON) = 1.6 Ω typ.) and ensure gate drive rise/fall times accommodate the 32 nC total gate charge to minimize switching losses in high-frequency applications.

Can the TK7A90E be used in avalanche mode, and what is its rated single-pulse energy?

Yes, the TK7A90E is fully rated for single-pulse avalanche operation with E_AS = 235 mJ at T_ch = 25 °C. This specification is tested and guaranteed per JEDEC standards, allowing the device to safely absorb inductive energy during switching transients - such as those occurring in flyback transformers or relay coils - without external clamping components. Operation beyond this limit or under repetitive avalanche conditions is not recommended and may degrade reliability.

What are the key thermal parameters of the TK7A90E, and how do they influence heatsink selection?

The TK7A90E specifies R_th(ch-c) = 2.78 °C/W (channel-to-case) and R_th(ch-a) = 62.5 °C/W (channel-to-ambient). For a 45 W power dissipation limit, the case-to-ambient thermal path must handle (150 − 25) °C ÷ 62.5 °C/W = 2 W - meaning the majority of heat must be removed via the case (heatsink). A heatsink with ≤1.5 °C/W thermal resistance (including interface material) is recommended to keep T_ch ≤150 °C at full 7 A DC load. Real-world layout and airflow significantly impact achievable R_th(ch-a).