onsemi KSH127TF

Overview

KSH127TF from ON Semiconductor is a PNP silicon Darlington transistor in D-PAK surface-mount package, rated for -100 V V_CEO, -8 A DC collector current, and 20 W collector dissipation at T_C = 25°C, with built-in emitter-collector damper diode and minimum h_FE of 1000 at I_C = -4 A. It serves as a high-gain power switch in industrial motor control and relay driver circuits.

For engineers reviewing the KSH127TF datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CE(sat) ≤ -2 V at I_C = -4 A / I_B = -16 mA, integrated damper diode functionality, D-PAK thermal performance, and compatibility with legacy TIP127-based layouts requiring surface-mount upgrade.

Technical Context

The KSH127TF implements a monolithic PNP Darlington pair with internal base-emitter resistors (R1 ≈ 8 kΩ, R2 ≈ 0.12 kΩ) enabling simplified biasing and improved turn-off speed versus standard Darlingtons. Its integrated emitter-collector damper diode suppresses inductive kickback without external components.

Designed for surface-mount operation, it leverages D-PAK's low thermal resistance (R_θJC ≈ 0.75°C/W typical) to sustain 20 W dissipation at case temperature ≤25°C, while maintaining safe operating area compliance up to I_C = -8 A and V_CE = -100 V under pulsed conditions (PW ≤ 300 µs, duty ≤ 2%).

Key Specifications

Pinout & Package

D-PAK (TO-252) surface-mount package with 3 terminals: tab-connected collector, isolated lead for emitter and base. Thermal pad on underside requires soldered connection to PCB copper for optimal heat transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP Darlington transistor applications.

Compared with KSH127TF, the KSH127 offers identical performance in bulk form but lacks tape-and-reel logistics support, while BDW93C trades integration and SMT compatibility for higher voltage rating and through-hole mechanical robustness-making KSH127TF optimal for space-constrained, high-volume industrial motor drivers needing integrated protection.

Availability

KSH127TF is available at Aetrix Electronics and suitable for industrial relay drivers, DC motor controllers, linear voltage regulators, and power supply OR-ing circuits requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.

Supply support for KSH127TF 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 (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing technologies, serving automotive, industrial, cloud, and medical markets with energy-efficient semiconductor solutions.

The KSH127TF belongs to ON Semiconductor's legacy power bipolar transistor family, designed specifically for high-current, high-gain switching in industrial control systems where reliability, thermal performance, and integrated protection reduce bill-of-materials cost.

FAQ

What is the maximum continuous collector current rating for the KSH127TF?

The KSH127TF is rated for -8 A DC collector current at T_C = 25°C. This rating assumes adequate heatsinking to maintain case temperature at or below 25°C. At higher case temperatures, derating applies per Figure 7 in the datasheet-e.g., at T_C = 100°C, maximum I_C drops to approximately -4.5 A. Always verify thermal design using the published R_θJC and R_θCA values for your PCB layout when applying the KSH127TF in production.

Does the KSH127TF include an integrated damper diode, and how is it configured?

Yes, the KSH127TF integrates an emitter-to-collector damper diode within the monolithic die. The diode's anode connects to the emitter terminal (Pin 3), and its cathode connects to the collector terminal (Pin 2). This configuration allows automatic clamping of inductive kickback voltages during switch-off events, eliminating the need for an external flyback diode in relay or solenoid driver applications using the KSH127TF.

What package type does the KSH127TF use, and what are its thermal characteristics?

The KSH127TF uses the D-PAK (TO-252) surface-mount package with a thermally enhanced metal tab. Its thermal resistance from junction to case (R_θJC) is approximately 0.75°C/W, enabling 20 W dissipation at T_C = 25°C. When mounted on a 1-in² 2-oz copper pad, typical R_θJA is ~60°C/W. These values are confirmed in the KSH127TF datasheet and essential for thermal validation in motor driver or regulator designs using the KSH127TF.

How does the KSH127TF compare to the TIP127 in terms of pin compatibility and performance?

The KSH127TF is electrically similar to the TIP127 but not pin-compatible: TIP127 uses TO-220 package with vertical pinout (E-B-C), while KSH127TF uses D-PAK with horizontal 3-pin layout (B-C-E). Both share -100 V V_CEO, -8 A I_C, and comparable h_FE, but KSH127TF adds the integrated damper diode and supports SMT assembly. Migration from TIP127 to KSH127TF requires PCB redesign but delivers improved reliability and reduced component count in new KSH127TF-based designs.

What is the minimum DC current gain (h_FE) of the KSH127TF, and under what conditions is it specified?

The KSH127TF guarantees a minimum DC current gain (h_FE) of 1000 at V_CE = -4 V and I_C = -4 A, per the official ON Semiconductor datasheet. This high gain enables low base drive current-approximately -4 mA-to fully saturate the device at rated load. The specification is validated across production lots and applies over the full operating temperature range (-65°C to +150°C), making the KSH127TF suitable for stable, low-power-control industrial applications.