onsemi KSH2955TF

Overview

KSH2955TF from ON Semiconductor is a PNP epitaxial silicon power transistor designed for general-purpose amplification and low-speed switching applications, featuring -60 V V_CEO, -10 A I_C, 20 W P_C (T_C=25°C), h_FE ≥20 at -4 A, and D-PAK surface-mount package - used in DC motor drivers, relay drivers, and linear power supply pass elements.

For engineers reviewing the KSH2955TF datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, high-current capability (-10 A), low saturation voltage (-1.1 V at -4 A/-0.4 A), junction temperature rating (150°C), and D-PAK thermal performance for industrial control and power management designs.

Technical Context

The KSH2955TF operates as a medium-power PNP bipolar junction transistor with fixed emitter-base and collector-base junction structures optimized for linear and saturated switching modes. Its DC current gain is specified down to -10 A, and f_T = 2 MHz (min) supports low-frequency signal amplification and pulse-width modulation control.

Thermal design relies on case-to-ambient conduction via the D-PAK's exposed drain pad (pin 2), with power derating starting at T_C > 25°C and full derating to zero at 150°C. Safe operating area (SOA) curves define simultaneous voltage/current limits under transient conditions, critical for inductive load switching.

Key Specifications

Pinout & Package

D-PAK (TO-252) surface-mount package with copper-exposed thermal pad on pin 2 (Collector); thermally enhanced for PCB heat spreading via soldered pad under body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955T4G and KSE2955T, the KSH2955TF delivers superior current handling and thermal efficiency in D-PAK form, making it optimal for high-density, high-reliability SMT power stages where board area and thermal resistance are constrained.

Availability

KSH2955TF is available at Aetrix Electronics and suitable for industrial motor drives, linear power supplies, and solid-state relay modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for KSH2955TF 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 management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSH2955TF belongs to Fairchild's legacy power transistor family, acquired by ON Semiconductor, and was engineered for ruggedized linear and switching power applications demanding high current, stable gain, and thermal resilience in harsh environments.

FAQ

What is the maximum junction temperature for the KSH2955TF?

The KSH2955TF has a maximum junction temperature (T_J) of 150°C, as specified in its absolute maximum ratings. This rating allows operation in high-ambient industrial environments when mounted on a properly sized PCB copper pour or heatsink. Thermal design must ensure that actual T_J remains below this limit under worst-case power dissipation and ambient conditions. The KSH2955TF's SOA curves and power derating graph provide guidance for safe thermal margins across load conditions.

Is the KSH2955TF pin-compatible with the KSE2955T?

No, the KSH2955TF is not pin-compatible with the KSE2955T. While both are PNP transistors with identical electrical specifications, the KSH2955TF uses a D-PAK (TO-252) package with pinout Base–Collector–Emitter, whereas the KSE2955T uses a TO-220 package with pinout Emitter–Base–Collector. PCB layout and thermal management must be redesigned to accommodate the KSH2955TF's surface-mount footprint and exposed collector pad. The KSH2955TF datasheet confirms this mechanical distinction explicitly.

What is the typical V_CE(sat) of the KSH2955TF at full rated current?

The typical V_CE(sat) of the KSH2955TF is -1.1 V at I_C = -4 A and I_B = -0.4 A. At the absolute maximum rated current of -10 A, V_CE(sat) rises to -1.8 V (max) per datasheet test condition. These values directly determine conduction losses: at -4 A, power dissipation is ~4.4 W; at -10 A, it reaches ~18 W - underscoring the need for adequate heatsinking. The KSH2955TF's low saturation voltage improves efficiency over older PNP alternatives.

Does the KSH2955TF require a base resistor, and how is it calculated?

Yes, the KSH2955TF requires an external base resistor to limit base current and ensure saturation. For example, to achieve I_B = -0.4 A at V_BE(on) ≈ -1.8 V (typ), with a 5 V logic driver referenced to emitter, R_B ≈ (5 V − 1.8 V) / 0.4 A = 8 Ω. The KSH2955TF's h_FE ≥20 at -4 A confirms sufficient overdrive. Always verify with actual V_BE(on) and driver voltage in the final circuit - the KSH2955TF's datasheet provides V_BE(on) curves across temperature and current.

Can the KSH2955TF be used in avalanche mode?

No, the KSH2955TF is not rated or characterized for avalanche operation. Its absolute maximum ratings specify V_CBO = -70 V and V_CEO = -60 V, but no avalanche energy (E_AS) or repetitive avalanche data is provided in the official datasheet. Using the KSH2955TF beyond V_CEO risks permanent degradation. For inductive switching, always implement clamping (e.g., snubber or freewheeling diode) - the KSH2955TF's safe operating area chart assumes non-avalanche conditions.