onsemi KST93MTF

Overview

KST93MTF from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon transistor designed for high-voltage switching and amplification in compact SOT-23 packages. It features -200 V collector-emitter breakdown voltage (BV_CEO), -500 mA continuous collector current (I_C), 350 mW power dissipation, and DC current gain (h_FE) of 25–40 at I_C = -10 mA, used in flyback snubber circuits and HV DC-DC converter bias rails.

For engineers reviewing the KST93MTF datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, SOT-23 terminal mapping (Base-Emitter-Collector), -200 V V_CEO rating, thermal resistance of 357 °C/W, and saturation voltage of -0.5 V at I_C = -20 mA / I_B = -2 mA.

Technical Context

This device operates as a medium-power, high-voltage PNP bipolar junction transistor with epitaxial base construction enabling stable gain and low leakage. Its BV_CBO = -200 V and BV_CEO = -200 V confirm robust blocking capability under open-base and open-emitter conditions respectively.

The KST93MTF delivers f_T = 50 MHz at V_CE = -20 V and I_C = -10 mA, supporting moderate-frequency switching; Cob = 8 pF at V_CB = -20 V ensures low capacitive loading in high-impedance node applications.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads; standardized 3-pin footprint measuring 2.90 mm × 1.30 mm × 1.00 mm (L × W × H), compatible with standard reflow profiles and automated placement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT93, the KST93MTF offers identical performance in the same footprint; versus ZTX951, it trades higher voltage margin and current capacity for smaller size and lower cost in space-constrained, sub-500 mA applications.

Availability

KST93MTF is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial I/O modules, and DC-DC bias rails requiring stable component supply, long-term obsolescence management, and consistent parametric performance across production lots.

Supply support for KST93MTF 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 supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and IoT applications.

The KST93MTF belongs to ON Semiconductor's legacy high-voltage discrete transistor family, engineered for reliability in ruggedized power conversion and signal conditioning circuits where voltage tolerance and thermal predictability are critical.

FAQ

What is the absolute maximum collector-emitter voltage rating for KST93MTF?

The absolute maximum collector-emitter voltage (V_CEO) for KST93MTF is -200 V at T_A = 25°C. This rating applies under open-base conditions and defines the upper limit of reverse bias the device can withstand without avalanche breakdown. Exceeding this voltage risks permanent damage, even briefly. The KST93MTF must be operated within this limit in all circuit configurations, including transient conditions.

Is KST93MTF pin-compatible with KST92MTF?

No, KST93MTF is not pin-compatible with KST92MTF in terms of electrical ratings, though both share the same SOT-23 package and pinout (Base-Emitter-Collector). The KST92MTF is rated for -300 V V_CEO, while KST93MTF is rated for -200 V. Substituting one for the other without verifying voltage stress margins may lead to premature failure in high-voltage applications. Always validate circuit operating points against the specific KST93MTF datasheet.

What is the typical DC current gain (h_FE) of KST93MTF at I_C = -10 mA?

The typical DC current gain (h_FE) of KST93MTF at V_CE = -10 V and I_C = -10 mA is 40, with a guaranteed minimum of 25. This value reflects the transistor's ability to amplify base current into collector current under those specific bias conditions. Designers should use the minimum h_FE for worst-case base drive calculations to ensure reliable saturation across process and temperature variations.

Can KST93MTF be used in linear amplifier configurations?

Yes, KST93MTF can be used in linear amplifier configurations, particularly for low-to-moderate frequency inverting stages where its 50 MHz f_T and stable h_FE provide adequate gain-bandwidth. However, its 350 mW power dissipation and thermal resistance require careful attention to quiescent current and heatsinking. For precision analog use, verify linearity and distortion specs at target operating points using the KST93MTF's published small-signal parameters.

What is the thermal resistance junction-to-ambient (R_TH(j-a)) for KST93MTF in SOT-23?

The thermal resistance junction-to-ambient (R_TH(j-a)) for KST93MTF in the standard SOT-23 package is 357 °C/W, measured under still-air conditions on FR-4 PCB with minimum copper pad. This value determines how much the junction temperature rises above ambient per watt of dissipated power. To maintain safe operation below 150°C junction temperature, average power dissipation in the KST93MTF must remain below ~350 mW at 25°C ambient, derating linearly at higher temperatures.