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

onsemi KST2222AMTF

Name: KST2222AMTF
Brand: onsemi
SKU: KST2222AMTF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KST2222AMTF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: KST2222AMTF.pdf

Description:: TRANS NPN 40V 0.6A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KST2222AMTF from ON Semiconductor is an NPN epitaxial silicon transistor in SOT-23 package, rated for 40 V V_CEO, 600 mA I_C, and 350 mW P_D, with DC current gain (h_FE) ranging from 35 to 300 depending on operating point. It serves as a general-purpose switching and amplification device in low-voltage digital logic interfaces and signal conditioning circuits.

For engineers reviewing the KST2222AMTF datasheet, pinout, applications, or equivalent options, key selection considerations include its 300 MHz f_T, 8 pF C_ob, 0.3 V V_CE(sat) at 150 mA/15 mA drive, and thermal resistance of 357 °C/W - all critical for high-speed switching, compact layout, and thermal-limited PCB designs.

Technical Context

This discrete NPN bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: 75 V V_CBO, 40 V V_CEO, and 6 V V_EBO. Its h_FE varies from 35 (at 0.1 mA) to 300 (at 10 mA), supporting both small-signal amplification and medium-current switching.

Dynamic performance includes 35 ns t_ON and 285 ns t_OFF under specified test conditions, with 4 dB noise figure at 1 MHz and 100 μA I_C. Output capacitance is 8 pF at 10 V V_CB, enabling predictable frequency response in RF-coupled or broadband amplifier stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in switching applications.
I_C	600 mA - Continuous collector current rating; sets maximum load drive capability without derating.
P_D	350 mW - Power dissipation at 25°C ambient; requires thermal design attention above 25°C due to 2.8 mW/°C derating.
f_T	300 MHz - Current gain bandwidth product; supports reliable operation up to ~100 MHz in common-emitter amplifiers.
C_ob	8 pF - Output capacitance at 10 V V_CB; impacts high-frequency gain roll-off and switching speed in capacitive-loaded circuits.
h_FE	35–300 - DC current gain range across 0.1–10 mA I_C; enables flexible biasing for analog gain or digital on/off control.
V_CE(sat)	0.3 V @ 150 mA/15 mA - Low saturation voltage reduces conduction loss in switch-mode operation.

Pinout & Package

SOT-23 3-lead plastic surface-mount package with standard footprint (JEDEC TO-236AB), optimized for automated assembly and space-constrained PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives base current to bias transistor into active or saturation region; requires current-limiting resistor in most digital drive configurations.
2 (Emitter)	Current return path	Common reference node for emitter-follower or grounded-emitter topologies; connected directly to GND or load return in switching applications.
3 (Collector)	Output current path	Delivers switched or amplified current to load; must be routed with adequate copper area to manage 357 °C/W thermal resistance.

Key Features

Feature	Design Value
General-purpose NPN BJT	Validated for use in both linear amplification and saturated switching across industrial temperature range (−55°C to +150°C).
High f_T (300 MHz)	Enables stable gain in VHF preamplifier stages and fast edge-rate digital buffer designs.
Low V_CE(sat) (0.3 V)	Minimizes power loss and self-heating during high-duty-cycle switching, improving efficiency in 3.3 V/5 V logic-level drivers.
Low C_ob (8 pF)	Reduces Miller effect in high-gain amplifier configurations, preserving bandwidth and stability margin.
Standard SOT-23 footprint	Ensures compatibility with existing pick-and-place equipment and reflow profiles used for 0.65 mm pitch components.

Applications

LED Driver Circuits	Microcontroller GPIO Expanders
Use Scenario: Driving 20–100 mA indicator or status LEDs from 3.3 V or 5 V MCU outputs. IC Role / Device Role / Timing Role: Switching element that translates logic-level signals into higher-current LED paths. Use Value: 0.3 V V_CE(sat) ensures >90% voltage headroom for LED forward drop, while 600 mA I_C rating allows parallel LED strings or future design margin.	Use Scenario: Adding discrete output capability to resource-constrained microcontrollers with limited native drive strength. IC Role / Device Role / Timing Role: Level-shifting and current-boosting interface between MCU GPIO and external loads (relays, solenoids, sensors). Use Value: 300 MHz f_T and 35–300 h_FE support clean edge transitions up to 10 MHz toggle rates, avoiding unintended oscillation or slow turn-off.
DC-DC Converter Feedback	Audio Signal Amplification
Use Scenario: Providing optocoupler drive current in isolated flyback converter feedback loops. IC Role / Device Role / Timing Role: Linear amplifier stage converting error amplifier output into proportional LED current for isolation barrier. Use Value: 4 dB noise figure and stable h_FE over 0.1–10 mA I_C ensure precise, low-noise current regulation critical for ±1% output voltage accuracy.	Use Scenario: Building low-noise preamplifier stages for electret microphone or sensor signal conditioning. IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with emitter degeneration for gain stability and linearity. Use Value: 8 pF C_ob and 300 MHz f_T allow flat frequency response up to 20 kHz with minimal phase shift, meeting audio band fidelity requirements.

LED Driver Circuits

Microcontroller GPIO Expanders

Use Scenario: Driving 20–100 mA indicator or status LEDs from 3.3 V or 5 V MCU outputs.

IC Role / Device Role / Timing Role: Switching element that translates logic-level signals into higher-current LED paths.

Use Value: 0.3 V V_CE(sat) ensures >90% voltage headroom for LED forward drop, while 600 mA I_C rating allows parallel LED strings or future design margin.

Use Scenario: Adding discrete output capability to resource-constrained microcontrollers with limited native drive strength.

IC Role / Device Role / Timing Role: Level-shifting and current-boosting interface between MCU GPIO and external loads (relays, solenoids, sensors).

Use Value: 300 MHz f_T and 35–300 h_FE support clean edge transitions up to 10 MHz toggle rates, avoiding unintended oscillation or slow turn-off.

DC-DC Converter Feedback

Audio Signal Amplification

Use Scenario: Providing optocoupler drive current in isolated flyback converter feedback loops.

IC Role / Device Role / Timing Role: Linear amplifier stage converting error amplifier output into proportional LED current for isolation barrier.

Use Value: 4 dB noise figure and stable h_FE over 0.1–10 mA I_C ensure precise, low-noise current regulation critical for ±1% output voltage accuracy.

Use Scenario: Building low-noise preamplifier stages for electret microphone or sensor signal conditioning.

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with emitter degeneration for gain stability and linearity.

Use Value: 8 pF C_ob and 300 MHz f_T allow flat frequency response up to 20 kHz with minimal phase shift, meeting audio band fidelity requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT2222ALT1G	Same die, identical absolute max ratings and electrical specs; differs only in tape/reel packaging (7" vs. 13") and marking ("1P" vs. "1AM").	No functional difference; fully interchangeable in schematic and layout.	Select based on preferred reel size and distributor inventory availability.
PN2222A	Through-hole TO-92 package; same V_CEO/I_C/h_FE specs but higher R_θJA (200 °C/W vs. 357 °C/W) and slower t_OFF (500 ns vs. 285 ns).	Suitable for prototyping or low-volume through-hole assemblies; not recommended for high-density or high-speed layouts.	Choose KST2222AMTF for SMT production; PN2222A only when manual assembly or legacy board compatibility is required.

Compared with MMBT2222ALT1G and PN2222A, the KST2222AMTF delivers identical electrical performance in a smaller SOT-23 footprint with faster switching and tighter thermal management - making it optimal for volume SMT manufacturing where board space and thermal budget are constrained.

Availability

KST2222AMTF is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, DC-DC converter feedback, and audio signal amplification requiring stable component supply and consistent parametric performance across production lots.

Supply support for KST2222AMTF 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 and signal management solutions, with leadership in automotive, industrial, cloud computing, and IoT applications.

The KST2222AMTF belongs to ON Semiconductor's general-purpose bipolar transistor product line, designed for cost-sensitive, high-reliability discrete switching and amplification in consumer, industrial, and communications equipment.

FAQ

What is the maximum continuous collector current rating for KST2222AMTF?

The KST2222AMTF has a maximum continuous collector current (I_C) rating of 600 mA at T_A = 25°C. This value decreases with rising ambient temperature due to its 2.8 mW/°C power derating slope and 357 °C/W junction-to-ambient thermal resistance. For sustained 600 mA operation, board-level thermal design must maintain case temperature below 25°C.

Does KST2222AMTF support high-frequency signal amplification?

Yes, the KST2222AMTF supports high-frequency signal amplification with a current gain bandwidth product (f_T) of 300 MHz under standard test conditions (I_C = 20 mA, V_CE = 20 V, f = 100 MHz). Its 8 pF output capacitance and 4 dB noise figure at 1 MHz make it suitable for VHF preamplifiers and broadband audio stages up to 20 kHz.

What is the pin configuration of KST2222AMTF in the SOT-23 package?

The KST2222AMTF uses standard SOT-23 pinout: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector. This matches JEDEC TO-236AB orientation and is compatible with automated placement equipment calibrated for 0.65 mm lead pitch. No alternate pinouts exist for this part number.

How does KST2222AMTF compare to the through-hole PN2222A?

The KST2222AMTF shares identical electrical specifications with the PN2222A (V_CEO = 40 V, h_FE = 35–300, f_T = 300 MHz) but differs in package: SOT-23 surface-mount versus TO-92 through-hole. KST2222AMTF offers faster turn-off (285 ns vs. 500 ns) and lower thermal resistance in compact layouts, while PN2222A suits hand-soldered prototypes.

Is KST2222AMTF RoHS compliant and halogen-free?

Yes, KST2222AMTF is RoHS compliant and halogen-free per ON Semiconductor's material declarations. The device meets EU Directive 2011/65/EU and IEC 61249-2-21:2011 standards. Full compliance documentation, including substance declarations and test reports, is available via ON Semiconductor's website using the KST2222AMTF part number.

KST2222AMTF 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:: NPN

Current - Collector (Ic) (Max):: 600 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 50mA, 500mA

Current - Collector Cutoff (Max):: 10nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 150mA, 10V

Power - Max:: 350 mW

Frequency - Transition:: 300MHz

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

KST2222AMTF FAQ

1.How can I place an order for KST2222AMTF through Aetrix?

Please submit a Request for Quotation (RFQ) for KST2222AMTF 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 KST2222AMTF reliable?

The price and inventory of KST2222AMTF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KST2222AMTF is usually 5 days.

3.What payment methods are accepted for KST2222AMTF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KST2222AMTF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KST2222AMTF?

KST2222AMTF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KST2222AMTF 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 KST2222AMTF?

For technical support, including KST2222AMTF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KST2222AMTF requirements.

6.How does Aetrix verify that KST2222AMTF is sourced from the original manufacturer or authorized distributors?

All KST2222AMTF 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 KST2222AMTF meets industry standards.

7.What is the process for return or replacement of KST2222AMTF?

All KST2222AMTF units undergo pre-shipment inspection (PSI). If there is an issue with KST2222AMTF, 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 KST2222AMTF part is unused and in its original packaging.

Return procedure for KST2222AMTF:

1.Submit a request within 90 days.

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

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