IRLZ44N — Logic-Level N-Channel Power MOSFET (55V, 47A)

Overview

The IRLZ44N is an N-channel logic-level power MOSFET manufactured by Infineon (formerly International Rectifier) in a TO-220AB package. Rated for $55\text{V}$ drain-source voltage ( $V_{DSS}$ ) and $47\text{A}$ continuous drain current ( $I_D$ ), it is engineered specifically for driving high-power DC loads directly from low-voltage digital microcontrollers.

Unlike standard power MOSFETs (such as the IRF540N or IRF520) that require $10\text{V}$ on the gate to fully turn on, the IRLZ44N features a low gate threshold voltage ( $V_{GS(th)} = 1.0\text{V} \dots 2.0\text{V}$ ). It achieves an ultra-low $R_{DS(on)}$ resistance of just $22\ \text{m}\Omega$ at $V_{GS} = 5.0\text{V}$ and $25\ \text{m}\Omega$ at $V_{GS} = 4.0\text{V}$ , making it the premier choice for 3.3V and 5V MCU PWM motor control, high-current LED strip dimming, and solenoid switching.

Quick reference


Transistor type	N-Channel Power MOSFET (Logic-Level Gate)
Package	TO-220AB (Pin 1: Gate, Pin 2: Drain/Tab, Pin 3: Source)
Drain-Source Voltage ( $V_{DSS}$ )	$55\text{ V}$ max
Continuous Drain Current ( $I_D$ )	$47\text{ A}$ (at $T_C = 25^\circ\text{C}$ , $V_{GS} = 10\text{V}$ )
Gate Threshold Voltage ( $V_{GS(th)}$ )	$1.0\text{ V}$ min / $2.0\text{ V}$ max
$R_{DS(on)}$ at $V_{GS} = 5.0\text{V}$	$22\ \text{m}\Omega$ ( $0.022\ \Omega$ )
$R_{DS(on)}$ at $V_{GS} = 4.0\text{V}$	$25\ \text{m}\Omega$ ( $0.025\ \Omega$ )
$R_{DS(on)}$ at $V_{GS} = 10\text{V}$	$17.5\ \text{m}\Omega$ ( $0.0175\ \Omega$ )
Max Power Dissipation ( $P_D$ )	$110\text{ W}$ (with heatsink)

Pinout (TO-220AB Package)

text

        ┌─────────┐
        │  TO-220 │
        │  IRLZ44 │
        └─┬───┬───┬─┘
          1   2   3
          G   D   S

Pin	Name	Description
1	`Gate` (`G`)	Control input (connected to MCU GPIO via $220\ \Omega$ series resistor)
2 / Tab	`Drain` (`D`)	High-power load switching output (connected to load negative terminal)
3	`Source` (`S`)	Ground reference (connected to common system ground)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Drain-Source Breakdown Volts	$V_{(BR)DSS}$	55	—	—	V	$V_{GS} = 0\text{V}, I_D = 250\ \mu\text{A}$
Gate-Source Threshold Volts	$V_{GS(th)}$	1.0	—	2.0	V	$V_{DS} = V_{GS}, I_D = 250\ \mu\text{A}$
Static Drain-Source On-Resist	$R_{DS(on)}$	—	18	22	mΩ	$V_{GS} = 5.0\text{V}, I_D = 25\text{A}$
Static Drain-Source On-Resist	$R_{DS(on)}$	—	21	25	mΩ	$V_{GS} = 4.0\text{V}, I_D = 21\text{A}$
Gate-Source Leakage Current	$I_{GSS}$	—	—	$\pm 100$	nA	$V_{GS} = \pm 16\text{V}$
Total Gate Charge	$Q_g$	—	32	48	nC	$V_{DS} = 44\text{V}, V_{GS} = 5.0\text{V}$
Diode Forward Voltage	$V_{SD}$	—	0.8	1.3	V	Internal body diode, $I_S = 25\text{A}$

Driving Circuit Topology

To switch high-power loads cleanly from an Arduino (5V) or ESP32 / Raspberry Pi (3.3V):

text

       +V_LOAD (12V - 24V DC)
          │
        [LOAD] (Motor / LED Strip / Solenoid)
          │
          ├──────────────┐
          │              │
        [Drain]      [Flyback Diode 1N4007] (For Inductive Loads Only)
     IRLZ44N MOSFET      │
        [Source] ────────┼─────── GND (Common System Ground)
          │              │
        [Gate]           │
          │              │
       [220Ω]            │
          │              │
     MCU GPIO Pin ───────┴─────── [10kΩ Pull-Down to GND]

$220\ \Omega$ Gate Resistor: Limits initial high-frequency capacitive gate charging current spikes into the MCU pin.
$10\ \text{k}\Omega$ Gate Pull-Down Resistor: Keeps the gate firmly at 0V during MCU bootup/reset, preventing accidental un-commanded load activation.
1N4007 Flyback Diode: Required across inductive loads (DC motors, relays, solenoids) to dissipate back-EMF voltage spikes.

Power Dissipation Math

$P_{dissipated} = I_{D}^2 \times R_{DS(on)}$

For a 5A LED Strip Load ( $V_{GS} = 5.0\text{V}$ ):

$P_{dissipated} = (5\text{A})^2 \times 0.022\ \Omega = 0.55\text{ Watts} \quad (\text{No heatsink required})$

For a 15A Motor Load ( $V_{GS} = 5.0\text{V}$ ):

$P_{dissipated} = (15\text{A})^2 \times 0.022\ \Omega = 4.95\text{ Watts} \quad (\text{TO-220 aluminum heatsink required})$

Common mistakes

Using standard IRF540N / IRF520 instead of IRLZ44N: Standard "IRF" series MOSFETs specify $R_{DS(on)}$ at $V_{GS} = 10\text{V}$ . When driven with $3.3\text{V}$ or $5.0\text{V}$ from an MCU, standard MOSFETs remain in their linear region, overheating rapidly under high currents.
Forgetting common ground: The MCU ground and the load power supply negative terminal must be connected together at the MOSFET Source pin.

Notes

IRLZ44N vs IRFZ44N: "L" indicates Logic-Level ( $V_{GS(th)} = 1.0\text{--}2.0\text{V}$ ); "F" indicates Standard-Gate ( $V_{GS(th)} = 2.0\text{--}4.0\text{V}$ , requires 10V gate drive).

Interface	Gate-Source Voltage Drive
Package	TO-220AB