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

onsemi KST63MTF

Name: KST63MTF
Brand: onsemi
SKU: KST63MTF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KST63MTF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KST63MTF.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KST63MTF from ON Semiconductor (formerly Fairchild) is a PNP epitaxial silicon Darlington transistor in SOT-23 package, rated for -30 V V_CEO, -500 mA I_C, and 350 mW P_C, used in low-power switching and signal amplification circuits such as LED drivers and sensor interface stages.

For engineers reviewing the KST63MTF datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain (h_FE = 5k–10k at I_C = -10 mA), V_CE(sat) ≤ -1.5 V at I_C = -100 mA, f_T = 125 MHz, and SOT-23 footprint compatibility with space-constrained PCB layouts.

Technical Context

The KST63MTF implements a two-stage PNP Darlington configuration to achieve high DC current gain while maintaining single-transistor SOT-23 integration. It operates with V_EB up to -10 V and supports continuous collector currents up to -500 mA under derated thermal conditions.

Its f_T of 125 MHz at V_CE = -5 V and I_C = -10 mA confirms usable bandwidth for audio-frequency switching and low-speed digital interfacing, while V_BE(on) = -2.0 V at I_C = -100 mA defines base drive requirements for saturation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-30 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C	-500 mA - Continuous collector current rating; sets upper limit for load-switching capability
P_C	350 mW - Total power dissipation at T_A = 25°C; requires thermal derating above ambient
h_FE	5,000–10,000 - High DC current gain enables low-base-drive-current operation in amplifier/switch stages
V_CE(sat)	≤ -1.5 V @ I_C = -100 mA, I_B = -0.1 mA - Low saturation voltage minimizes conduction loss in switching applications
f_T	125 MHz @ V_CE = -5 V, I_C = -10 mA - Bandwidth sufficient for audio and low-MHz digital signal handling

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads; compact 2.90 mm × 1.30 mm × 1.00 mm footprint and standard JEDEC MO-178 alignment.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input terminal; requires ~0.1 mA base current to saturate at 100 mA collector load
2	Emitter	Current source terminal; connected to higher potential rail in PNP switching configurations
3	Collector	Output terminal; sinks current to ground or lower-potential node when active

Key Features

Feature	Design Value
Darlington architecture	Two cascaded PNP transistors integrated in one SOT-23 die, delivering h_FE ≥ 5k without external bias network
Low V_CE(sat)	-1.5 V max ensures <150 mW conduction loss at 100 mA, improving efficiency in battery-powered loads
High f_T	125 MHz enables stable operation up to ~10 MHz square-wave switching with minimal phase lag
SOT-23 compatibility	Standard footprint allows drop-in replacement for other SOT-23 PNP transistors like MMBT6427 or DXT631

Applications

LED Driver Stage	Sensor Signal Amplifier
Use Scenario: Driving medium-brightness indicator LEDs from microcontroller GPIO pins with limited sink current. IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current sinking capability with minimal base drive. Use Value: Enables direct GPIO control of 100 mA LED strings without external driver ICs or resistive base dividers.	Use Scenario: Amplifying weak analog output from NTC thermistors or photodiodes in portable instrumentation. IC Role / Device Role / Timing Role: Low-noise, high-gain PNP preamplifier stage operating in common-collector configuration. Use Value: Delivers >50 dB voltage gain at DC–100 kHz with predictable h_FE and low V_BE drift over temperature.
Level-Shifting Interface	Low-Power Relay Driver
Use Scenario: Translating 3.3 V logic signals to control 5 V or 12 V peripheral enable lines. IC Role / Device Role / Timing Role: Inverting level shifter using emitter-follower or common-emitter topology. Use Value: Supports bidirectional voltage translation up to 30 V with <100 ns propagation delay due to 125 MHz f_T.	Use Scenario: Activating 5 V/12 V electromagnetic relays in industrial control modules with MCU-level base drive. IC Role / Device Role / Timing Role: Final-stage PNP switch delivering full coil current with low saturation loss. Use Value: Reduces relay coil power loss by 30% vs. standard PNP transistors due to -1.5 V V_CE(sat) at 100 mA.

LED Driver Stage

Sensor Signal Amplifier

Use Scenario: Driving medium-brightness indicator LEDs from microcontroller GPIO pins with limited sink current.

IC Role / Device Role / Timing Role: PNP Darlington switch providing high-current sinking capability with minimal base drive.

Use Value: Enables direct GPIO control of 100 mA LED strings without external driver ICs or resistive base dividers.

Use Scenario: Amplifying weak analog output from NTC thermistors or photodiodes in portable instrumentation.

IC Role / Device Role / Timing Role: Low-noise, high-gain PNP preamplifier stage operating in common-collector configuration.

Use Value: Delivers >50 dB voltage gain at DC–100 kHz with predictable h_FE and low V_BE drift over temperature.

Level-Shifting Interface

Low-Power Relay Driver

Use Scenario: Translating 3.3 V logic signals to control 5 V or 12 V peripheral enable lines.

IC Role / Device Role / Timing Role: Inverting level shifter using emitter-follower or common-emitter topology.

Use Value: Supports bidirectional voltage translation up to 30 V with <100 ns propagation delay due to 125 MHz f_T.

Use Scenario: Activating 5 V/12 V electromagnetic relays in industrial control modules with MCU-level base drive.

IC Role / Device Role / Timing Role: Final-stage PNP switch delivering full coil current with low saturation loss.

Use Value: Reduces relay coil power loss by 30% vs. standard PNP transistors due to -1.5 V V_CE(sat) at 100 mA.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT6427	Lower h_FE (100–300), higher V_CE(sat) (-1.8 V), same SOT-23 package	Less suitable for ultra-low-base-drive designs; better for fast-switching where gain stability matters more than drive efficiency	Select MMBT6427 when prioritizing switching speed over current gain; verify base resistor recalibration needed
DXT631	Higher I_C rating (-800 mA), same V_CEO, slightly higher P_C (500 mW)	Supports heavier relay or solenoid loads; requires larger thermal pad or airflow in sustained operation	Choose DXT631 for >500 mA peak loads; confirm PCB copper area meets 500 mW dissipation requirement

Compared with MMBT6427 and DXT631, the KST63MTF offers optimal balance of high h_FE, low V_CE(sat), and SOT-23 footprint-making it preferred for space-limited, low-base-drive, medium-current switching where thermal headroom is constrained.

Availability

KST63MTF is available at Aetrix Electronics and suitable for LED driver circuits, sensor interface stages, level-shifting interfaces, and low-power relay drivers requiring stable component supply across production volumes.

Supply support for KST63MTF 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, high-performance silicon solutions for automotive, industrial, cloud computing, and IoT applications.

The KST63MTF belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, designed specifically for cost-sensitive, space-constrained analog and discrete switching functions in consumer and industrial electronics.

FAQ

What is the maximum collector current rating for the KST63MTF?

The KST63MTF has a maximum continuous collector current (I_C) rating of -500 mA at T_A = 25°C. Derating is required above ambient temperature per the datasheet thermal resistance curve. Pulse operation allows higher peak currents (e.g., -1 A) under strict duty cycle and pulse width limits defined in the Absolute Maximum Ratings table. Always verify junction temperature rise in final layout using R_θJA = 357°C/W.

Does the KST63MTF have a documented Darlington configuration?

Yes, the KST63MTF is explicitly specified as a PNP Darlington transistor in the original Fairchild datasheet (Rev. A2, November 2002). Its h_FE range of 5,000–10,000 at I_C = -10 mA and V_CE = -5 V-orders of magnitude higher than standard PNP transistors-confirms integrated Darlington architecture. The device integrates two PNP transistors on a single die within the SOT-23 package.

What is the typical V_CE(sat) for the KST63MTF under standard test conditions?

The typical V_CE(sat) for the KST63MTF is -1.5 V when tested at I_C = -100 mA and I_B = -0.1 mA, per the Electrical Characteristics table. This value reflects guaranteed maximum performance under pulsed conditions (PW ≤ 300 µs, duty cycle ≤ 2%). In DC operation, V_CE(sat) may increase slightly due to self-heating; design margin should include ±0.1 V tolerance.

Can the KST63MTF replace the KST64MTF in a circuit?

No-the KST63MTF and KST64MTF are distinct variants with different h_FE profiles: KST63MTF specifies h_FE = 5k–10k at I_C = -10 mA, while KST64MTF specifies h_FE = 10k–20k at I_C = -100 mA. Substituting KST63MTF for KST64MTF may cause insufficient gain in high-current, low-base-drive applications. Verify h_FE requirements at target operating point before interchange.

Is the KST63MTF RoHS compliant and lead-free?

Yes, the KST63MTF is RoHS compliant and lead-free. As a legacy ON Semiconductor part originally manufactured by Fairchild, it conforms to JEDEC J-STD-609 Category 1a marking and meets EU RoHS Directive 2011/65/EU requirements. The SOT-23 package uses matte tin (Sn) lead finish, and material declarations are available via ON Semiconductor's compliance portal under part number KST63MTF.

KST63MTF 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:: 10000 @ 100mA, 5V

Power - Max:: 350 mW

Frequency - Transition:: 125MHz

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

KST63MTF FAQ

1.How can I place an order for KST63MTF through Aetrix?

Please submit a Request for Quotation (RFQ) for KST63MTF 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 KST63MTF reliable?

The price and inventory of KST63MTF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KST63MTF is usually 5 days.

3.What payment methods are accepted for KST63MTF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KST63MTF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KST63MTF?

KST63MTF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KST63MTF 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 KST63MTF?

For technical support, including KST63MTF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KST63MTF requirements.

6.How does Aetrix verify that KST63MTF is sourced from the original manufacturer or authorized distributors?

All KST63MTF 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 KST63MTF meets industry standards.

7.What is the process for return or replacement of KST63MTF?

All KST63MTF units undergo pre-shipment inspection (PSI). If there is an issue with KST63MTF, 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 KST63MTF part is unused and in its original packaging.

Return procedure for KST63MTF:

1.Submit a request within 90 days.

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

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