onsemi KSP94TA

Overview

KSP94TA from ON Semiconductor is a PNP epitaxial silicon transistor designed for high-voltage switching applications, featuring V_CEO = −400 V, I_C = −300 mA, and V_CE(sat) = −750 mV at I_C = −50 mA / I_B = −5 mA. It operates in TO-92 3L package and serves as a complement to the KSP44 NPN device in dual-switch or level-shift circuits.

For engineers reviewing the KSP94TA datasheet, pinout, applications, or equivalent options, key selection criteria include breakdown voltage margin in flyback snubbers, saturation performance under pulsed base drive, thermal derating in enclosed power supplies, and compatibility with legacy Fairchild-designated PCB footprints.

Technical Context

The KSP94TA implements a planar epitaxial PNP structure optimized for high-voltage blocking with low leakage (I_CES ≤ −1 μA at V_CE = −400 V) and stable DC current gain (h_FE = 40–300 across I_C = −1 to −100 mA). Its junction temperature rating of 150°C supports operation in thermally constrained industrial control modules.

Thermal resistance R_θJA = 200°C/W and 625 mW total dissipation enable use in discrete switch stages where active cooling is impractical. The device's Cob = 7 pF at V_CB = −20 V supports moderate-frequency switching (<100 kHz) without excessive capacitive loading on driver stages.

Key Specifications

Pinout & Package

Package: TO-92 3L molded plastic case, straight-lead or bent-lead configuration per JEDEC TO-92 standard; compatible with standard through-hole reflow and wave soldering profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955G and BCP53-16, the KSP94TA uniquely balances 400 V blocking, TO-92 mountability, and sub-1 V saturation in a cost-sensitive through-hole solution-making it optimal for retrofitting legacy AC-powered equipment without layout changes.

Availability

KSP94TA is available at Aetrix Electronics and suitable for AC-DC auxiliary power supplies, industrial relay drivers, flyback snubbers, and linear voltage regulator pass elements requiring stable component supply across long-lifecycle industrial programs.

Supply support for KSP94TA 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, sensor, and logic solutions for automotive, industrial, cloud computing, and consumer markets.

The KSP94TA belongs to ON Semiconductor's legacy discrete bipolar transistor portfolio, originally developed by Fairchild Semiconductor to address high-voltage switching needs in cost-sensitive industrial and power supply applications.

FAQ

What is the maximum continuous collector current rating for KSP94TA?

The KSP94TA has an absolute maximum continuous collector current (I_C) of −300 mA at T_A = 25°C. Derating applies above 25°C at 5.0 mW/°C, limiting usable current in enclosed environments. For sustained operation at −100 mA, junction temperature remains within 150°C limit with proper PCB copper area per datasheet Figure 5 layout guidelines. Always verify thermal performance in final KSP94TA application using measured ambient and power dissipation.

Is KSP94TA pin-compatible with the original Fairchild KSP94BU?

Yes, the KSP94TA shares identical TO-92 3L package dimensions, pinout (Emitter-Base-Collector), and mechanical form factor with KSP94BU. Both use straight-lead or bent-lead configurations per JEDEC TO-92, enabling direct PCB footprint reuse. Electrical specifications are identical per Rev. 1.5 datasheet, confirming functional equivalence for legacy design refreshes. No layout change is required when substituting KSP94TA for KSP94BU.

Does KSP94TA support switching frequencies above 100 kHz?

The KSP94TA is not optimized for high-frequency switching: its output capacitance (C_ob = 7 pF) and stored charge characteristics result in turn-off delays unsuitable for >100 kHz operation. It performs reliably in <50 kHz applications such as relay driving, snubbing, and auxiliary supply regulation. For higher-frequency use, consider complementary MOSFETs or RF-optimized BJTs-KSP94TA should be selected only where voltage rating and thermal robustness outweigh speed requirements.

What is the typical DC current gain (h_FE) of KSP94TA at low collector current?

At V_CE = −10 V and I_C = −1 mA, the KSP94TA exhibits h_FE ≥ 40 (minimum), with typical values near 100. This gain supports efficient base drive from microcontrollers or logic gates with minimal current sourcing. Gain decreases slightly at higher currents (e.g., h_FE = 45 at I_C = −50 mA), remaining stable enough for predictable saturation in switching applications. Always validate h_FE in actual KSP94TA circuit conditions due to unit-to-unit variation.

Can KSP94TA be used in avalanche mode?

No, the KSP94TA is not rated or characterized for intentional avalanche operation. Its BV_CEO = −400 V is a DC breakdown limit under specified test conditions (I_C = −1 mA, I_B = 0); operation near this voltage without current limiting risks irreversible degradation. For avalanche-rated devices, select ON Semiconductor's dedicated avalanche transistors (e.g., MJE13009) instead of relying on KSP94TA beyond its absolute maximum ratings.