2N7002 MOSFET Equivalent Circuit, Pinout and Features
The 2N7002 is a widely used N-channel enhancement mode MOSFET, typically packaged in a compact SOT-23 form factor. It is designed for high-speed switching applications and features low gate charge and low on-resistance, making it particularly suitable for power management and load switching in portable and low-power devices.
Pin Configuration (SOT-23 Package)
The 2N7002 comes in a three-terminal SOT-23 package:
Gate (G): The control terminal where voltage is applied to turn the MOSFET on or off.
Drain (D): The terminal through which current flows into the MOSFET when it is on.
Source (S): The terminal through which current flows out of the MOSFET when it is on.
When viewed from the flat side of the SOT-23 package with leads facing downward:
Left pin → Source (S)
Center pin → Gate (G)
Right pin → Drain (D)
Equivalent Circuit
Key Features
The 2N7002 offers a set of characteristics that make it a popular choice in a variety of electronic applications:
N-Channel MOSFET: Utilizes positive gate-to-source voltage for conduction.
Low Voltage Operation: Optimized for low-voltage systems.
Low Gate Threshold Voltage: With a typical Vgs(th) of ~2.5V, it can be driven by relatively low control voltages, making it ideal for signal-level switching.
Drain Current Capability: Provides a continuous drain current of ~115mA at 25°C, sufficient for many low-power applications.
Wide Operating Temperature Range: Operates reliably between -55°C and +150°C.
Compact SOT-23 Package: Space-saving, surface-mount design suitable for modern compact electronics.
Low On-Resistance (Rds(on)): Approximately 7.5Ω, reducing power loss during conduction.
Equivalent N-Channel MOSFETs
Several alternatives can be used in place of the 2N7002 depending on circuit requirements:
BS170: Similar electrical characteristics but offered in a larger TO-92 package.
BSS138: Close electrical match, also available in SOT-23, and can serve as a drop-in replacement in many designs.
AO3400 / AO3400A: Higher current-handling capability in SOT-23 package, suitable for applications requiring lower Rds(on).
When selecting an equivalent device, always compare datasheets carefully. Critical parameters include:
Maximum voltages (Vds, Vgs)
Current ratings (Id, Idm)
Power dissipation (Pd)
Threshold voltage (Vgs(th))
On-resistance (Rds(on))
Typical Applications
Thanks to its compact size, cost-effectiveness, and efficient switching performance, the 2N7002 is used in a wide range of electronic circuits, especially low-power and signal-level systems. Typical applications include:
Low-Voltage Circuits: Supports operation up to 60V drain-source voltage with 115mA continuous drain current.
Signal Switching: Suitable for signal-level switching due to its low gate threshold voltage (~2.5V).
Power Management: Widely used in portable devices and low-power digital or analog systems.
Load Switching: Effective for low-power load switching in battery-operated and energy-sensitive designs.
Small Motor Control: Can drive miniature motors in lightweight applications.
The 2N7002 is a versatile, general-purpose N-channel MOSFET that delivers reliable performance in compact, low-power systems. While it is not designed for high-current loads, it remains a go-to choice for signal switching, power management, and small-scale load driving. Designers should always verify key electrical parameters against their application requirements by consulting the device datasheet.
