The 2N5401 is a high-voltage PNP bipolar junction transistor (BJT) designed for low-power switching and signal amplification. Its high collector-emitter voltage rating makes it particularly useful in circuits where higher voltages must be controlled at relatively low current levels.
Supplied in a compact TO-92 through-hole package, the 2N5401 is commonly used in telecommunication equipment, high-voltage signal circuits, amplifier stages, switching circuits, and general electronic applications. Its complementary NPN transistor is the 2N5551.
Pin Configuration
A commonly used TO-92 pin configuration is:
Pin 1 – Emitter: PNP emitter terminal.
Pin 2 – Base: Controls transistor conduction.
Pin 3 – Collector: PNP collector terminal.
Important: TO-92 pin arrangements can vary between manufacturers. Always verify the datasheet for the exact 2N5401 supplied before installation or PCB assembly.
Technical Specifications
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Transistor Type: PNP Bipolar Junction Transistor (BJT)
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Package: TO-92
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Collector-Emitter Voltage (VCEO): -150V Max.
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Collector-Base Voltage (VCBO): -160V Max.
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Emitter-Base Voltage (VEBO): -5V Max.
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Collector Current (IC): Up to -600mA Max.
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DC Current Gain (hFE): Device- and operating-condition dependent; up to approximately 100 as specified
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Maximum Power Dissipation: Approx. 625mW under specified conditions
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Operating Junction Temperature: Up to +150°C
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Mounting Type: Through-Hole
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Complementary NPN Transistor: 2N5551
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Lead-Free Versions: Available depending on manufacturer
How the 2N5401 Works
As a PNP transistor, the 2N5401 begins conducting when its base is driven sufficiently below its emitter voltage.
For a silicon PNP transistor, the forward base-emitter voltage magnitude is typically around 0.6-0.7V when conducting. The 5V specification refers to the maximum emitter-base reverse voltage (VEBO) and is not the normal voltage required to turn the transistor on.
The amount of collector current depends on the operating conditions and available base drive.
Using the 2N5401 as a Switch
The 2N5401 can be used as a switching transistor in circuits requiring a PNP device with a relatively high voltage rating.
When used as a switch, the transistor typically operates between:
Cut-Off: The transistor is off and collector current is minimal.
Saturation: The transistor is driven on sufficiently to provide a low-voltage conduction path between emitter and collector.
A correctly sized base resistor should be used to limit base current and ensure reliable switching.
When controlled from a microcontroller, additional interface circuitry may be necessary, particularly when the transistor's emitter operates at a voltage higher than the microcontroller's GPIO voltage.
Using the 2N5401 as an Amplifier
The 2N5401 can also operate in its active region for signal amplification. Its relatively high voltage capability makes it useful in amplifier stages and other circuits where the transistor must withstand higher voltages than common low-voltage general-purpose transistors.
Actual current gain varies according to collector current, collector-emitter voltage, temperature, and individual device characteristics.
Complementary Pair with 2N5551
The 2N5401 PNP is commonly paired with the 2N5551 NPN transistor in complementary circuit designs.
The pair can be used in amplifier stages, signal processing circuits, switching circuits, driver stages, and other applications requiring complementary high-voltage NPN and PNP transistors.
Applications
The 2N5401 is suitable for high-voltage low-current switching, signal amplification, telecommunication equipment, telephone circuits, amplifier stages, driver circuits, complementary transistor circuits, industrial electronics, and general-purpose electronic projects.
Important Notes
The 600mA collector-current rating is an absolute maximum rating, not necessarily a recommended continuous operating current. Safe current depends on collector-emitter voltage, power dissipation, ambient temperature, thermal conditions, and the manufacturer's safe operating area.
Similarly, the maximum power-dissipation rating applies only under specified thermal conditions and should not be treated as available power under all operating conditions.
For inductive loads such as relays, solenoids, or motors, appropriate transient protection such as a flyback diode should be used.
Always verify the electrical ratings and pin configuration against the datasheet for the exact manufacturer supplied.
Package Includes
1 × 2N5401 PNP Transistor
