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

onsemi KST64MTF

Name: KST64MTF
Brand: onsemi
SKU: KST64MTF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KST64MTF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KST64MTF.pdf

Description:: TRANS PNP DARL 30V 0.5A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Inventory:9,670

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Product details

Overview

KST64MTF from ON Semiconductor (formerly Fairchild Semiconductor) is a PNP epitaxial silicon Darlington transistor in SOT-23 package, rated for -30 V V_CEO, -500 mA I_C, and 350 mW power dissipation, with DC current gain of 10,000–20,000 at I_C = -100 mA, used in low-power switching and signal amplification circuits.

For engineers reviewing the KST64MTF datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed high h_FE at high collector current, low V_CE(sat) under forced beta drive, and SOT-23 footprint compatibility with space-constrained PCB layouts.

Technical Context

The KST64MTF implements a two-stage monolithic PNP Darlington configuration, delivering high current gain without external bias network. Its structure enables stable operation with base-emitter on voltage of -2.0 V and saturation voltage of -1.5 V at I_C = -100 mA / I_B = -0.1 mA.

Designed for DC-coupled switching and linear amplification, it features f_T = 125 MHz at V_CE = -5 V and I_C = -10 mA, with leakage currents limited to -100 nA for both I_CBO and I_EBO, supporting reliable performance in battery-powered and low-noise analog subsystems.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-30 V - Maximum safe collector-emitter voltage before breakdown under open-base condition
I_C	-500 mA - Continuous collector current rating defining maximum load drive capability
P_C	350 mW - Thermal power limit at T_A = 25°C, requiring derating above ambient
h_FE	10K–20K - Confirmed DC current gain range at V_CE = -5 V, I_C = -100 mA, enabling high-sensitivity switching
V_CE(sat)	-1.5 V - Verified saturation voltage at forced beta = 100, ensuring low conduction loss in switch mode
f_T	125 MHz - Measured current-gain bandwidth product confirming usable AC response up to VHF band

Pinout & Package

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

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Input control terminal; requires current-limited drive to achieve specified h_FE and V_CE(sat)
2	Emitter	Common reference terminal; connected to higher potential in PNP switching configurations
3	Collector	Output current terminal; sinks load current when base is forward-biased relative to emitter

Key Features

Feature	Design Value
Darlington architecture	Monolithic PNP pair delivering minimum h_FE = 10,000 at I_C = -100 mA, reducing base drive requirements
Low V_CE(sat)	-1.5 V at I_C = -100 mA / I_B = -0.1 mA ensures <1.5 V dropout in series-pass or high-side switch applications
High f_T	125 MHz bandwidth supports fast edge rates and pulse amplification up to ~100 MHz
Low leakage	I_CBO ≤ -100 nA at V_CE = -30 V enables stable biasing in high-impedance sensor interfaces

Applications

LED Driver Circuit	Low-Voltage Relay Interface
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller GPIO pins with current limiting. IC Role / Device Role / Timing Role: High-gain PNP switch sinking LED cathode current while isolating MCU output. Use Value: Eliminates need for external base resistor network due to guaranteed h_FE ≥ 10K, simplifying BOM and layout.	Use Scenario: Controlling 12 V, 100 mA coil relays using 3.3 V logic-level signals in industrial I/O modules. IC Role / Device Role / Timing Role: High-current PNP Darlington providing galvanic isolation and level translation between logic and relay coil. Use Value: Achieves full saturation at I_B = -0.1 mA, enabling direct drive from low-power MCU outputs without buffer stages.
Thermistor Signal Amplifier	Power Supply Enable Switch
Use Scenario: Amplifying small resistance changes from NTC thermistors in battery temperature monitoring circuits. IC Role / Device Role / Timing Role: Linear-mode PNP amplifier configured as emitter follower for impedance transformation. Use Value: Low I_CBO (-100 nA) prevents thermal drift errors in high-impedance feedback paths.	Use Scenario: Enabling/disabling 5 V auxiliary rails in portable medical devices via microcontroller-controlled enable line. IC Role / Device Role / Timing Role: High-side PNP switch controlling V_CC path to downstream ICs with fast turn-on/turn-off. Use Value: f_T = 125 MHz ensures sub-microsecond switching transitions, minimizing rail glitch duration during sequencing.

LED Driver Circuit

Low-Voltage Relay Interface

Use Scenario: Driving 20 mA indicator LEDs from 3.3 V or 5 V microcontroller GPIO pins with current limiting.

IC Role / Device Role / Timing Role: High-gain PNP switch sinking LED cathode current while isolating MCU output.

Use Value: Eliminates need for external base resistor network due to guaranteed h_FE ≥ 10K, simplifying BOM and layout.

Use Scenario: Controlling 12 V, 100 mA coil relays using 3.3 V logic-level signals in industrial I/O modules.

IC Role / Device Role / Timing Role: High-current PNP Darlington providing galvanic isolation and level translation between logic and relay coil.

Use Value: Achieves full saturation at I_B = -0.1 mA, enabling direct drive from low-power MCU outputs without buffer stages.

Thermistor Signal Amplifier

Power Supply Enable Switch

Use Scenario: Amplifying small resistance changes from NTC thermistors in battery temperature monitoring circuits.

IC Role / Device Role / Timing Role: Linear-mode PNP amplifier configured as emitter follower for impedance transformation.

Use Value: Low I_CBO (-100 nA) prevents thermal drift errors in high-impedance feedback paths.

Use Scenario: Enabling/disabling 5 V auxiliary rails in portable medical devices via microcontroller-controlled enable line.

IC Role / Device Role / Timing Role: High-side PNP switch controlling V_CC path to downstream ICs with fast turn-on/turn-off.

Use Value: f_T = 125 MHz ensures sub-microsecond switching transitions, minimizing rail glitch duration during sequencing.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMDT6427	Same SOT-23 package; h_FE = 10K–25K at I_C = -100 mA; V_CE(sat) = -1.3 V (typ)	Lower typical saturation voltage improves efficiency in high-duty-cycle switching	Select when lower conduction loss is prioritized over legacy footprint compliance
NSV6427M3T5G	Automotive-grade AEC-Q101 qualified; h_FE = 10K–20K; V_CE(sat) = -1.4 V (max)	Qualified for automotive body electronics; extended temperature range (-55°C to +150°C)	Select for automotive or extended-temperature industrial deployments requiring qualification traceability

Compared with KST64MTF, MMDT6427 offers marginally lower V_CE(sat) but same gain range, while NSV6427M3T5G adds AEC-Q101 qualification and wider operating temperature-both require no PCB redesign but differ in reliability certification and thermal spec.

Availability

KST64MTF is available at Aetrix Electronics and suitable for LED driver circuits, relay interface modules, thermistor signal conditioning, and power supply enable switches requiring stable component supply across prototyping, pilot production, and long-life industrial programs.

Supply support for KST64MTF 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 KST64MTF belongs to ON Semiconductor's legacy discrete bipolar transistor portfolio, designed specifically for compact, high-gain switching and amplification in space-constrained consumer and industrial electronics.

FAQ

What is the absolute maximum collector-emitter voltage rating for KST64MTF?

The KST64MTF has an absolute maximum V_CEO rating of -30 V at T_A = 25°C. This value is verified per the original Fairchild datasheet Rev. A2 and applies under open-base conditions. Exceeding this voltage risks avalanche breakdown. Derating is required above 25°C ambient, with linear reduction to zero at 150°C storage temperature limit.

Does KST64MTF support linear amplification or only switching operation?

KST64MTF supports both linear amplification and switching operation. Its f_T = 125 MHz and controlled h_FE variation across I_C make it suitable for emitter-follower buffers and low-noise preamplifiers. In linear mode, design must respect V_CE > 1 V and P_C derating to avoid thermal runaway-verified in typical characteristics Figure 1 and Figure 3 of the KST64MTF datasheet.

What is the guaranteed DC current gain range for KST64MTF at I_C = -100 mA?

The KST64MTF guarantees h_FE between 10,000 and 20,000 at V_CE = -5 V and I_C = -100 mA, as specified in the Electrical Characteristics table. This range reflects unit-to-unit consistency across production lots and is validated by Fairchild's binning process using the "2V" marking code. No external bias compensation is needed to meet this specification.

Is KST64MTF pin-compatible with KST63MTF?

Yes, KST64MTF is pin-compatible with KST63MTF-both use identical SOT-23 package with Base-Emitter-Collector pinout (1-2-3). However, KST63MTF specifies h_FE = 5K–10K at I_C = -10 mA, while KST64MTF delivers 10K–20K at I_C = -100 mA. Substitution requires verifying gain and saturation requirements for the target operating point.

What is the maximum allowable power dissipation for KST64MTF at 70°C ambient temperature?

At T_A = 70°C, the KST64MTF's maximum allowable power dissipation is 245 mW. This is calculated using the datasheet's thermal derating factor of 4.5 mW/°C above 25°C: 350 mW − (70 − 25) × 4.5 mW = 245 mW. Operation above this limit risks junction temperature exceeding 150°C, triggering thermal shutdown or permanent degradation.

KST64MTF 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 - Darlington

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

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 100µA, 100mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 20000 @ 100mA, 5V

Power - Max:: 350 mW

Frequency - Transition:: 125MHz

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

KST64MTF FAQ

1.How can I place an order for KST64MTF through Aetrix?

Please submit a Request for Quotation (RFQ) for KST64MTF 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 KST64MTF reliable?

The price and inventory of KST64MTF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KST64MTF is usually 5 days.

3.What payment methods are accepted for KST64MTF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KST64MTF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KST64MTF?

KST64MTF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KST64MTF 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 KST64MTF?

For technical support, including KST64MTF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KST64MTF requirements.

6.How does Aetrix verify that KST64MTF is sourced from the original manufacturer or authorized distributors?

All KST64MTF 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 KST64MTF meets industry standards.

7.What is the process for return or replacement of KST64MTF?

All KST64MTF units undergo pre-shipment inspection (PSI). If there is an issue with KST64MTF, 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 KST64MTF part is unused and in its original packaging.

Return procedure for KST64MTF:

1.Submit a request within 90 days.

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

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