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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi KST92MTF

Name: KST92MTF
Brand: onsemi
SKU: KST92MTF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KST92MTF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: KST92MTF.pdf

Description:: TRANS PNP 300V 0.5A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KST92MTF from ON Semiconductor is a PNP epitaxial silicon transistor designed for high-voltage switching and amplification in discrete power control circuits, with −300 V collector-base and collector-emitter breakdown voltage, −500 mA continuous collector current, and 350 mW power dissipation in SOT-23 package.

For engineers reviewing the KST92MTF datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, thermal characteristics, SOT-23 terminal mapping, and validated alternative transistors for high-voltage PNP replacement in industrial power supplies, relay drivers, and overvoltage protection circuits.

Technical Context

The KST92MTF operates as a general-purpose PNP bipolar junction transistor with fixed emitter-base and collector-base junctions optimized for stable DC gain (h_FE = 25–40 at IC = −1 to −30 mA) and low saturation voltages (V_CE(sat) = −0.5 V at IC = −20 mA, IB = −2 mA). Its 50 MHz f_T supports moderate-speed switching up to ~100 kHz.

Thermal design relies on its 357 °C/W junction-to-ambient resistance and −55 °C to +150 °C operating range, enabling use in non-derated ambient conditions up to +85 °C when mounted on standard FR-4 PCB with minimal copper area. Output capacitance (C_ob = 6 pF at V_CB = −20 V) limits high-frequency gain roll-off.

Key Specifications

Parameter	Value and Actual Design Meaning
VCBO / VCEO	−300 V - Supports operation in circuits with up to 300 V reverse bias across collector-base or collector-emitter terminals without breakdown.
IC (Continuous)	−500 mA - Delivers reliable DC current sourcing capability for driving relays, solenoids, or logic-level interface loads.
PC (Max)	350 mW - Limits usable power handling in SOT-23; requires thermal derating above +85 °C ambient or with minimal PCB copper.
hFE (DC Gain)	25–40 - Provides predictable base drive requirements for saturation switching; gain drops at higher currents, requiring design margin.
VCE(sat)	−0.5 V - Ensures low conduction loss when fully turned on, critical for minimizing heat generation in linear or saturated-mode applications.
fT	50 MHz - Enables stable small-signal amplification and switching up to mid-frequency ranges; not suitable for RF or >1 MHz digital edge control.

Pinout & Package

SOT-23 3-lead plastic surface-mount package (JEDEC TO-236AB), low-profile, tape-and-reel packaged (KST92MTF marking "2D"). Dimensions per MA03D Rev. 1.0 drawing: 2.92 mm × 1.30 mm × 1.00 mm height, 0.65 mm pitch.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives negative base current to turn on the PNP; requires current-limiting resistor to prevent damage during saturation.
2 (Emitter)	Current source terminal	Connected to positive rail in common-emitter configuration; carries full load current and defines reference for base bias.
3 (Collector)	Output terminal	Drains current from load to ground or lower potential; reverse-biased up to −300 V relative to base/emitter.

Key Features

Feature	Design Value
High-voltage PNP structure	−300 V VCBO/VCEO enables direct replacement of legacy high-voltage PNP transistors in industrial power rails and flyback snubbers.
Low VCE(sat)	−0.5 V at −20 mA ensures <10 mW conduction loss per switch cycle, reducing thermal stress in repetitive switching applications.
Stable hFE over current range	hFE remains ≥25 from −1 mA to −30 mA, simplifying base drive design without dynamic compensation networks.
Low Cob	6 pF output capacitance minimizes Miller effect in switching nodes, supporting clean turn-off in inductive load drivers.

Applications

Industrial Relay Drivers	High-Voltage Power Supply Feedback
Use Scenario: Driving 24–48 V DC relays with coil currents up to 400 mA in programmable logic controllers and factory automation I/O modules. IC Role / Device Role / Timing Role: PNP switch controlling relay coil current path from positive rail to ground via collector-emitter path. Use Value: −300 V rating prevents breakdown during inductive kickback; −0.5 V VCE(sat) keeps relay driver losses below 200 mW at full load.	Use Scenario: Isolating and scaling error amplifier output in offline AC/DC converters with >300 V primary-side rails. IC Role / Device Role / Timing Role: Level-shifting PNP buffer stage translating feedback signal from optocoupler output to PWM controller reference input. Use Value: High VCBO withstands transient spikes on primary side; 50 MHz fT preserves loop stability up to 100 kHz switching frequency.
Overvoltage Protection Circuits	Discrete Logic-Level Translation
Use Scenario: Clamping surge events on 24 V or 48 V DC bus lines using crowbar or foldback topology in telecom power systems. IC Role / Device Role / Timing Role: Fast-turn-on PNP element triggering SCR-based shutdown when bus voltage exceeds threshold via Zener-biased base. Use Value: −5 V VEBO allows precise Zener reference biasing; −0.9 V VBE(sat) ensures rapid activation under overvoltage fault conditions.	Use Scenario: Converting 3.3 V or 5 V microcontroller GPIO outputs to −12 V or −24 V logic levels for industrial sensor interfaces. IC Role / Device Role / Timing Role: Inverting level shifter with emitter-follower or common-emitter configuration to generate negative logic signals. Use Value: Predictable hFE (25–40) enables accurate base resistor calculation; SOT-23 footprint saves board space versus through-hole alternatives.

Industrial Relay Drivers

High-Voltage Power Supply Feedback

Use Scenario: Driving 24–48 V DC relays with coil currents up to 400 mA in programmable logic controllers and factory automation I/O modules.

IC Role / Device Role / Timing Role: PNP switch controlling relay coil current path from positive rail to ground via collector-emitter path.

Use Value: −300 V rating prevents breakdown during inductive kickback; −0.5 V VCE(sat) keeps relay driver losses below 200 mW at full load.

Use Scenario: Isolating and scaling error amplifier output in offline AC/DC converters with >300 V primary-side rails.

IC Role / Device Role / Timing Role: Level-shifting PNP buffer stage translating feedback signal from optocoupler output to PWM controller reference input.

Use Value: High VCBO withstands transient spikes on primary side; 50 MHz fT preserves loop stability up to 100 kHz switching frequency.

Overvoltage Protection Circuits

Discrete Logic-Level Translation

Use Scenario: Clamping surge events on 24 V or 48 V DC bus lines using crowbar or foldback topology in telecom power systems.

IC Role / Device Role / Timing Role: Fast-turn-on PNP element triggering SCR-based shutdown when bus voltage exceeds threshold via Zener-biased base.

Use Value: −5 V VEBO allows precise Zener reference biasing; −0.9 V VBE(sat) ensures rapid activation under overvoltage fault conditions.

Use Scenario: Converting 3.3 V or 5 V microcontroller GPIO outputs to −12 V or −24 V logic levels for industrial sensor interfaces.

IC Role / Device Role / Timing Role: Inverting level shifter with emitter-follower or common-emitter configuration to generate negative logic signals.

Use Value: Predictable hFE (25–40) enables accurate base resistor calculation; SOT-23 footprint saves board space versus through-hole alternatives.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT92T1G	Same die, identical electrical specs, but ON Semiconductor's updated part number post-Fairchild integration (underscore → dash).	No functional difference; used interchangeably where MMBT92T1G is specified in newer BOMs.	Select MMBT92T1G if sourcing from ON Semiconductor's current catalog; KST92MTF remains valid for legacy designs and existing stock.
PN2907A	Lower VCBO/VCEO (−60 V), higher VCE(sat) (−1.6 V), TO-92 package - not pin-compatible and unsuitable for >100 V applications.	Limited to low-voltage logic and signal switching; cannot replace KST92MTF in high-voltage rails or relay drivers above 60 V.	Only consider PN2907A for cost-sensitive, low-voltage prototyping where −300 V rating is unnecessary.

Compared with MMBT92T1G, KST92MTF offers identical performance but reflects Fairchild's original nomenclature; versus PN2907A, KST92MTF delivers 5× higher voltage tolerance and 3× lower saturation loss, making it essential for industrial 24–48 V+ systems requiring robust overvoltage resilience.

Availability

KST92MTF is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage power supply feedback circuits, and overvoltage protection systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for KST92MTF 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, sensors, and discrete devices for automotive, industrial, cloud computing, and IoT applications.

The KST92MTF belongs to ON Semiconductor's legacy Fairchild discrete transistor portfolio, engineered for rugged high-voltage switching in industrial power conversion, motor control, and protection circuitry where reliability under transient stress is critical.

FAQ

What is the maximum collector-emitter voltage rating for the KST92MTF?

The KST92MTF has a guaranteed −300 V collector-emitter breakdown voltage (V_CEO) at I_C = −1 mA and T_A = 25 °C. This rating allows safe operation in circuits with up to 300 V reverse bias across the collector-emitter junction, such as flyback transformer snubbers or high-side switching nodes. Derating is required above 25 °C ambient per the device's thermal characteristics.

Is the KST92MTF pin-compatible with the MMBT92T1G?

Yes - the KST92MTF and MMBT92T1G share identical SOT-23 pinout (Base-Emitter-Collector on pins 1-2-3), identical die, and identical electrical specifications. The MMBT92T1G is ON Semiconductor's rebranded version following the Fairchild integration, with underscore replaced by dash. No PCB changes are needed when substituting KST92MTF with MMBT92T1G.

What is the typical DC current gain (hFE) of the KST92MTF at different collector currents?

The KST92MTF exhibits h_FE = 25 at I_C = −1 mA, h_FE = 40 at I_C = −10 mA, and h_FE = 25 again at I_C = −30 mA (all measured at V_CE = −10 V, T_A = 25 °C). This non-monotonic behavior indicates peak gain near mid-current range, requiring careful base resistor selection to ensure saturation across the full operating load range of the KST92MTF.

Can the KST92MTF be used in switching power supplies above 100 kHz?

The KST92MTF has a current gain bandwidth product (f_T) of 50 MHz, but its practical switching speed is limited by storage time and saturation recovery. For hard-switched topologies, reliable operation is confirmed up to ~100 kHz; beyond that, switching losses increase significantly due to slow turn-off. For >100 kHz designs, consider faster transistors like the NSS12201LT1G or dedicated MOSFETs instead of the KST92MTF.

Does the KST92MTF require heatsinking in standard SOT-23 mounting?

No external heatsink is required for the KST92MTF under typical conditions: at I_C = −20 mA and V_CE = −0.5 V, power dissipation is only 10 mW. Even at full rated I_C = −500 mA and V_CE(sat) = −0.5 V (250 mW), the SOT-23 package can operate without heatsink up to +85 °C ambient when mounted on 1-inch² 1-oz copper. Thermal derating curves in the KST92MTF datasheet must be followed for higher ambient or sustained loads.

KST92MTF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 300 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 2mA, 20mA

Current - Collector Cutoff (Max):: 250nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 25 @ 30mA, 10V

Power - Max:: 250 mW

Frequency - Transition:: 50MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

KST92MTF FAQ

1.How can I place an order for KST92MTF through Aetrix?

Please submit a Request for Quotation (RFQ) for KST92MTF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for KST92MTF reliable?

The price and inventory of KST92MTF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KST92MTF is usually 5 days.

3.What payment methods are accepted for KST92MTF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KST92MTF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KST92MTF?

KST92MTF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KST92MTF order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for KST92MTF?

For technical support, including KST92MTF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KST92MTF requirements.

6.How does Aetrix verify that KST92MTF is sourced from the original manufacturer or authorized distributors?

All KST92MTF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that KST92MTF meets industry standards.

7.What is the process for return or replacement of KST92MTF?

All KST92MTF units undergo pre-shipment inspection (PSI). If there is an issue with KST92MTF, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The KST92MTF part is unused and in its original packaging.

Return procedure for KST92MTF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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