IRLB8743 — 30V 150A Extreme Low RDS(on) Logic-Level N-Channel MOSFET (TO-220)

Overview

The IRLB8743 (IRLB8743PBF) is an ultra-low on-resistance 30V, 150A N-channel logic-level power MOSFET manufactured by Infineon Technologies (formerly International Rectifier) in a through-hole TO-220AB package.

Engineered with advanced trench technology, it achieves an extraordinarily low $R_{DS(on)}$ of $3.2\text{ m}\Omega$ at $V_{GS} = 10\text{V}$ and $4.2\text{ m}\Omega$ at $V_{GS} = 4.5\text{V}$ . Even when driven by $3.3\text{V}$ and $5.0\text{V}$ microcontrollers, it can switch massive continuous loads ( $20\text{A} \dots 50\text{A}$ ) with virtually negligible conduction losses ( $P_{diss} = I^2 \times R_{DS(on)} = 20^2 \times 0.0042 = 1.68\text{ W}$ ). It is the premier choice for high-power 3D printer heated beds, brushless/brushed DC motor speed controllers, electronic speed controllers (ESCs), and high-efficiency synchronous buck converters.

Quick reference


Transistor Type	N-Channel Logic-Level Power MOSFET
Package	TO-220AB (Pin 1: Gate, Pin 2: Drain/Tab, Pin 3: Source)
Drain-Source Voltage ( $V_{DSS}$ )	$30\text{ V}$ max
Continuous Drain Current ( $I_D$ )	$150\text{ A}$ (Silicon Limit, $T_C = 25^\circ\text{C}$ ) / $75\text{ A}$ (Package Limit)
Gate Threshold Voltage ( $V_{GS(th)}$ )	$1.35\text{ V}$ min to $2.35\text{ V}$ max
On-Resistance ( $R_{DS(on)}$ )	$3.2\text{ m}\Omega$ at $10\text{V}$ / $4.2\text{ m}\Omega$ at $4.5\text{V}$
Pulsed Drain Current ( $I_{DM}$ )	$600\text{ A}$
Total Power Dissipation ( $P_D$ )	$140\text{ W}$ ( $T_C = 25^\circ\text{C}$ )

Terminal identification

text

        ┌─────────┐
        │  TO-220 │
        │ LB8743  │
        └─┬───┬───┬─┘
          1   2   3
          G   D   S

Pin	Terminal	Description
1	`Gate` (`G`)	Gate control input (Connect to MCU GPIO via $100\ \Omega$ series resistor)
2 / Tab	`Drain` (`D`)	High-power load switching terminal / Tab (Connect to load negative return)
3	`Source` (`S`)	Source terminal (Connect to Common System Ground 0 V)

Specifications

Parameter	Symbol	Min	Typ	Max	Unit	Conditions
Drain-Source Breakdown Voltage	$V_{(BR)DSS}$	30	—	—	V	$V_{GS} = 0\text{V}, I_D = 250\ \mu\text{A}$
Gate Threshold Voltage	$V_{GS(th)}$	1.35	1.80	2.35	V	$V_{DS} = V_{GS}, I_D = 50\ \mu\text{A}$
On-Resistance ( $V_{GS} = 10\text{V}$ )	$R_{DS(on)}$	—	2.5	3.2	mΩ	$V_{GS} = 10\text{V}, I_D = 40\text{A}$
On-Resistance ( $V_{GS} = 4.5\text{V}$ )	$R_{DS(on)}$	—	3.1	4.2	mΩ	$V_{GS} = 4.5\text{V}, I_D = 32\text{A}$
Gate-to-Drain Charge	$Q_{gd}$	—	8.8	—	nC	$V_{DS} = 15\text{V}, V_{GS} = 4.5\text{V}, I_D = 32\text{A}$
Total Gate Charge	$Q_g$	—	21	32	nC	$V_{DS} = 15\text{V}, V_{GS} = 4.5\text{V}, I_D = 32\text{A}$
Turn-On Delay Time	$t_{d(on)}$	—	19	—	ns	$V_{DD} = 15\text{V}, I_D = 32\text{A}, R_G = 3.0\ \Omega$
Turn-Off Delay Time	$t_{d(off)}$	—	17	—	ns	$V_{DD} = 15\text{V}, I_D = 32\text{A}, R_G = 3.0\ \Omega$

Typical circuits

High-Current DC Motor / ESC Low-Side Driver (12V/24V up to 30A)

text

        +12V / +24V High-Current Supply
           │
         [ DC MOTOR (Up to 30A Continuous) ]
           │
           ├─── [ Schottky Flyback Diode (e.g. MBR20100CT) across Motor ]
           │
        [Pin 2: DRAIN]
         IRLB8743
        [Pin 3: SOURCE] ─── GND (Heavy Gauge Wire to Power Supply Negative)
           │
        [Pin 1: GATE] ◄───[ R_gate = 100Ω ]───◄ MCU PWM Output (3.3V / 5V)
           │
        [ R_pulldown = 100kΩ ]
           │
          GND

Selection & substitutes

Part Number	$V_{DSS}$	Continuous $I_D$	$R_{DS(on)}$ at 4.5V	Best Used For
IRLB8743	$30\text{ V}$	$150\text{ A}$ (75A pkg)	$4.2\text{ m}\Omega$	Extreme current loads ( $20\text{A} \dots 50\text{A}$ )
IRLB8721	$30\text{ V}$	$62\text{ A}$	$13.1\text{ m}\Omega$	Moderate high-current loads ( $5\text{A} \dots 20\text{A}$ ), ultra-fast switching
IRLZ44N	$55\text{ V}$	$47\text{ A}$	$25\text{ m}\Omega$	Higher voltage loads up to 48V

Common mistakes

Package lead current limit ( $75\text{ A}$ ): While the internal silicon die is rated for $150\text{ A}$ , standard TO-220 wire bonds and terminal pins are limited to a maximum continuous current of $75\text{ A}$ .
Exceeding $30\text{V}$ $V_{DSS}$ breakdown voltage: The IRLB8743 must not be used on circuits exceeding 24V nominal (such as 36V or 48V e-bike batteries), as inductive spikes will exceed the $30\text{V}$ breakdown rating. Use the IRL540N (100V) for higher voltage supplies.

Notes

Suffix Identification: The standard lead-free model number is IRLB8743PBF.

Interface	3.3V, 4.5V, and 10V Gate Drive Compatible
Package	TO-220AB