IRFZ44N Overview: High-Power N-Channel MOSFET
Introduction
The IRFZ44N is a high-power N-channel MOSFET widely used in applications requiring high current and voltage switching or amplification. It's especially popular in power supply circuits, motor control, and general-purpose high-speed switching.
Specifications
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Type: N-Channel Enhancement Mode
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Package: TO-220
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Applications: DC-DC converters, motor drivers, battery protection circuits, power switches
Maximum Ratings (at 25°C):
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Drain-Source Voltage (VDS): 55V
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Gate-Source Voltage (VGS): ±20V
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Continuous Drain Current (ID): 49A
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Pulsed Drain Current (IDM): 160A
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Power Dissipation (PD): 94W
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Operating/Storage Temperature (TJ, Tstg): -55°C to +175°C
Thermal Resistance:
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Junction-to-Case (RθJC): 1.0°C/W
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Junction-to-Ambient (RθJA): 62°C/W
Electrical Characteristics (Typical at 25°C):
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Gate Threshold Voltage (VGS(th)): 2.0–4.0V
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On-Resistance (RDS(on)) at VGS = 10V: ≤ 0.022Ω
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Gate Leakage Current (IGSS): ±100nA
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Input Capacitance (Ciss): Approx. 1350pF
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Rise Time / Fall Time: Approx. 60ns / 45ns
IRFZ44N Pinout
The IRFZ44N comes in a TO-220 package with three pins:
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Gate: Control input. Apply 10V for full enhancement and conduction.
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Drain: Connects to the load. Handles the main current.
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Source: Usually connected to ground in low-side switching configurations.
Typical Switching Circuit Explanation
A common configuration is low-side switching:
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Gate is driven by a control signal (often with a series resistor).
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Source is tied to ground.
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Drain connects to one side of the load, with the other side connected to the power supply (e.g., 12V battery).
How It Works:
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Gate LOW (<2V): MOSFET is OFF. No current flows through the load.
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Gate HIGH (~10V): MOSFET turns ON. Current flows from Drain to Source, powering the load.
With its very low RDS(on), the MOSFET generates minimal heat during conduction and handles large currents efficiently.
Usage Notes:
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Use a gate voltage of around 10V for full enhancement; 5V logic may not be sufficient.
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A gate resistor (10–100Ω) is often added to limit inrush current.
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Use a flyback diode across inductive loads (like motors or relays) to protect the MOSFET.
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For high-current applications, attach a heatsink to manage thermal dissipation.
Conclusion
The IRFZ44N is a cost-effective and robust N-channel MOSFET ideal for high-current switching. Thanks to its low on-resistance, fast switching, and strong current-handling capabilities, it is widely used in DIY electronics, automotive systems, battery management, and industrial control. With proper gate driving and thermal management, it performs reliably in demanding environments.