onsemi KSH41CTF

Overview

KSH41CTF from ON Semiconductor is an NPN epitaxial silicon power transistor in D-PAK surface-mount package, rated for 100 V V_CEO, 6 A DC collector current, and 20 W collector dissipation at T_C = 25°C. It serves as a general-purpose amplifier and low-speed switching device in DC-DC converters, motor drivers, and relay drivers.

For engineers reviewing the KSH41CTF datasheet, pinout, applications, or equivalent options, key selection criteria include its 100 V blocking capability, 1.5 V V_CE(sat) at 6 A/600 mA drive, h_FE range of 30–75, junction temperature limit of 150°C, and D-PAK thermal performance for board-level power handling.

Technical Context

The KSH41CTF operates as a medium-power bipolar junction transistor with fixed-emitter configuration and base-controlled conduction. Its design supports linear amplification and saturated switching, with verified V_CEO(sus) = 100 V under zero-base-drive conditions and f_T = 3 MHz at V_CE = 10 V, I_C = 500 mA.

Thermal derating begins at T_C > 25°C, with linear reduction to zero dissipation at 175°C case temperature. Safe operating area (SOA) data confirms pulsed capability up to I_CP = 10 A with PW ≤ 300 µs and duty cycle ≤ 2%, enabling short-duration overload tolerance in protection circuits.

Key Specifications

Pinout & Package

Package: D-PAK (TO-252), surface-mount, single-ended heat sink tab (drain-connected to collector). Dimensions: 6.60 × 9.50 × 2.30 mm (L × W × H), with exposed thermal pad on collector side.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Compared with KSH41CTF, BU508AF trades gain for voltage robustness while maintaining thermal form factor, whereas MJD122G improves drive sensitivity at the cost of blocking voltage-both require validation of SOA and thermal layout against target load profiles.

Availability

KSH41CTF is available at Aetrix Electronics and suitable for DC-DC converters, motor drivers, relay interfaces, and linear regulator designs requiring stable component supply, consistent parametric performance, and long-term industrial availability.

Supply support for KSH41CTF 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSH41CTF belongs to ON Semiconductor's legacy Fairchild power bipolar transistor portfolio, designed for cost-sensitive, medium-power linear and switching applications where ruggedness, thermal reliability, and proven performance outweigh ultra-high-speed requirements.

FAQ

What is the maximum continuous collector current rating for KSH41CTF?

The KSH41CTF has a maximum DC collector current rating of 6 A at case temperature T_C = 25°C. This rating assumes adequate PCB copper area for thermal conduction from the D-PAK collector tab. At elevated case temperatures, current must be derated per the published power derating curve, reaching zero at T_C = 175°C. Pulse current up to 10 A is allowed for ≤300 µs with ≤2% duty cycle.

Does KSH41CTF have a documented pinout compatible with standard D-PAK footprints?

Yes, the KSH41CTF uses the industry-standard D-PAK (TO-252) package with pin 1 = Base, pin 2 = Collector (connected to exposed thermal pad), and pin 3 = Emitter. Its mechanical dimensions match JEDEC MO-220 specifications, and the pinout is electrically and physically identical to other D-PAK NPN transistors like MJD122G and FZT651, enabling direct PCB footprint reuse.

How does the V_CE(sat) of KSH41CTF compare to TIP41C under equivalent operating conditions?

At I_C = 6 A and I_B = 600 mA, the KSH41CTF specifies V_CE(sat) ≤ 1.5 V, while the through-hole TIP41C typically exhibits V_CE(sat) ≈ 2.0 V under the same conditions. This 0.5 V reduction lowers conduction loss by ~3 W at full load, improving thermal margin and efficiency in surface-mount implementations where heatsinking is constrained.

Is KSH41CTF suitable for linear regulator applications requiring high safe operating area (SOA)?

Yes, the KSH41CTF includes published SOA curves confirming operation up to 100 V × 0.1 A (DC), 30 V × 1 A (10 ms), and 10 V × 6 A (100 µs). Its 20 W DC power rating and 150°C junction limit make it viable as a series pass element in adjustable linear regulators delivering up to 3–4 A, provided thermal design meets the derating profile and transient loads remain within SOA boundaries.

What is the guaranteed minimum h_FE for KSH41CTF at I_C = 3 A?

The KSH41CTF guarantees h_FE ≥ 15 at V_CE = 4 V and I_C = 3 A, per its official datasheet. This minimum gain ensures predictable base drive requirements in saturated switching applications-for example, 200 mA base current suffices to maintain 3 A collector current. At I_C = 0.3 A, h_FE is guaranteed ≥30, supporting low-current amplification modes.