IRLZ44N N-Channel Power MOSFET
A true logic-level power MOSFET whose on-resistance is specified at just 5V gate drive, letting it switch tens of amps directly from a microcontroller pin without a separate gate driver — the standard choice for motor and high-current LED-strip switching in maker projects.
How this component works
An N-Channel MOSFET is a voltage-controlled semiconductor switch, making it fundamentally different from current-controlled bipolar transistors (like the NPN). To turn a MOSFET on, you simply apply a voltage to its Gate relative to its Source.
Because the Gate is electrically isolated from the rest of the transistor by a microscopic layer of glass (silicon dioxide), it draws virtually zero continuous current. This makes MOSFETs incredibly easy to drive directly from microcontrollers. Once turned fully on, the path between Drain and Source acts like a very low-value resistor (Rds_on), allowing them to switch massive currents (often 10A to 50A) with minimal heat.
They are the backbone of modern power electronics, dominating motor drivers, 3D printer heated beds, and high-speed switching power supplies.
Deep Dive: IRLZ44N MOSFET
The detail that matters most for the IRLZ44N is where on its datasheet the on-resistance is measured: RDS(on) ≈ 0.022Ω at Vgs = 5V. That single spec is the actual engineering definition of a logic-level MOSFET — not simply having a low threshold voltage, which the 2N7000 in this category also has, but having its full low-resistance conducting state guaranteed at a voltage a microcontroller pin can actually supply. At 5V gate drive, this part reaches a genuinely low on-resistance, meaning very little power is wasted as heat in the MOSFET itself even while switching large currents, which is what makes it practical to drive directly from an Arduino or similar microcontroller output with no separate gate-driver IC in between.
That capability is why it's the standard choice for motor control, PWM LED-strip dimming, and relay/solenoid driving in maker projects — loads that routinely draw well over the 2N7000's 200mA ceiling. Its 47A datasheet rating is a package/junction limit, not a practical continuous rating without a heatsink, but even derated significantly it still comfortably outperforms the 2N7000 by orders of magnitude for these jobs. As with any inductive load (a motor or relay coil), a flyback diode is still required across the load regardless of MOSFET choice — the IRLZ44N's logic-level drive solves the gate-voltage problem, not the separate issue of inductive kickback.
Common Use Cases
- Switching DC motors directly from a microcontroller pin without a dedicated gate-driver IC
- PWM dimming of high-current LED strips
- Driving a relay coil or solenoid load that draws more current than a small-signal MOSFET like the 2N7000 can handle
Frequently Asked Questions
What actually makes the IRLZ44N a "logic-level" MOSFET, as opposed to a regular power MOSFET?
The key detail is that its datasheet on-resistance (RDS(on) ≈ 0.022Ω) is specified at Vgs = 5V, not the 10V figure common on many other power MOSFETs like the 2N7000 in this category. That means it reaches its full low-resistance conducting state from a standard 5V microcontroller pin, not just partially.
Can I really switch a motor with this directly from an Arduino pin, with no extra driver circuitry?
Yes for the switching itself — the 5V-rated RDS(on) means the gate turns on fully from a microcontroller pin — but a flyback diode across an inductive load like a motor or relay coil is still required to protect the MOSFET from voltage spikes when the load is switched off.
Why is the IRLZ44N in a much bigger package than the 2N7000?
Its TO-220 package is sized to dissipate the heat generated by switching much higher currents (up to 47A on the datasheet, though real-world continuous current is thermally limited well below that without a heatsink) — a small TO-92 package like the 2N7000's simply couldn't handle that power dissipation.
Comparison Notes
Unlike the 2N7000 in this category, the IRLZ44N's on-resistance is specified at Vgs = 5V — the defining trait of a true logic-level MOSFET — letting it fully switch tens of amps directly from a microcontroller pin, whereas the 2N7000 only partially turns on at that same gate voltage.