From a 3.3 V or 5 V pin
| Pin | Verdict | Why | In free air |
|---|---|---|---|
| ESP32 · 3.3 V | Not guaranteed | nothing guaranteed below 4.5 V | — |
| Arduino Uno · 5 V | Works | RDS(on) at most 16 mΩ guaranteed from 4.5 V | 8.8 A (heat) |
In free air at 25 °C, with the junction 25 °C below its 175 °C maximum and θJA 62 °C/W, at the guaranteed RDS(on) raised with temperature.
Specifications
| Type | N-channel MOSFET |
|---|---|
| Package | TO-220 |
| Maximum voltage | 30 V |
| Maximum current | 62 A |
| Threshold VGS(th) | 1.35 … 2.35 V |
| RDS(on), maximum | 16 mΩ at 4.5 V (25 A) · 8.7 mΩ at 10 V (31 A) |
| Gate voltage limit | ±20 V |
| Gate charge | 13 nC at 4.5 V |
| Thermal resistance | θJA 62 °C/W · θJC 2.3 °C/W |
| Maximum junction temperature | 175 °C |
| Datasheet used | Infineon |
Pinout
| Pin | Function |
|---|---|
| 1 | Gate |
| 2 | Drain |
| 3 | Source |
Printed face toward you, leads down: pin 1 is on the left. The metal tab is connected to pin 2.
Similar parts
| Part | Package | RDS(on) at 3.3 V | RDS(on) at 5 V | Max voltage | Max current |
|---|---|---|---|---|---|
| IRLB8721 | TO-220 | no | 16 mΩ | 30 V | 62 A |
| 2N7000 | TO-92 | no | 5.3 Ω | 60 V | 200 mA |
| BS170 | TO-92 | no | no | 60 V | 500 mA |
| AO3400A | SOT-23 | 48 mΩ | 32 mΩ | 30 V | 5.7 A |
| Si2302 | SOT-23 | 75 mΩ | 57 mΩ | 20 V | 2.6 A |
| IRLML6344 | SOT-23 | 37 mΩ | 29 mΩ | 30 V | 5 A |
| IRLZ44N | TO-220 | no | 25 mΩ | 55 V | 47 A |
| IRF520 | TO-220 | no | no | 100 V | 9.2 A |
| IRF540N | TO-220 | no | no | 100 V | 33 A |
Tips
Keep the 10 kΩ from gate to ground: while the microcontroller boots its pins float and the MOSFET could turn on by itself.
Every coil needs a flyback diode across it, cathode to the positive supply. Without it the voltage spike at turn-off can destroy the transistor at the first switching.
A TO-220 in free air sheds little heat: fit a heatsink, insulated if the tab must not touch it (the tab is the drain or collector).
Open the calculator →Check the IRLB8721 with your own load, supply, PWM frequency and temperature.
Other transistors
2N2222A 2N3904 BC547 S8050 TIP120 2N7000 BS170 AO3400A Si2302 IRLML6344 IRLZ44N IRF520 IRF540N AO3401A IRF9540N
Frequently asked questions
Does the IRLB8721 work with a 3.3 V ESP32?
Not reliably: the threshold is at most 2.35 V, but RDS(on) is guaranteed only from 4.5 V. It may switch small currents, nothing more is promised. Use a MOSFET guaranteed at 2.5 V such as the AO3400A.
How much current can the IRLB8721 switch without a heatsink?
About 8.8 A from a 5 V Arduino pin, in free air at 25 °C, keeping the junction 25 °C below its 175 °C maximum (limit: heat).
What is the IRLB8721 pinout?
TO-220: 1 gate, 2 drain, 3 source. Printed face toward you, leads down: pin 1 is on the left. The metal tab is connected to pin 2.
Source of the figures: Infineon datasheet (PDF)