STB140N4F8 - 40V, 120A N-Channel Power MOSFET | STMicroelectronics
MPN: STB140N4F8 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.28 | $228.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.85 | $1,850.00 |
Drop-in alternatives for STB140N4F8 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STB120N4F6
✅ Drop-In📋 Reference alternative (not in catalog)
STB140N4F8-1
✅ Drop-In📋 Reference alternative (not in catalog)
STB140N4F8T4
✅ Drop-In📋 Reference alternative (not in catalog)
IPB120N04S4-02
✅ Drop-In📋 Reference alternative (not in catalog)
IRF1404
✅ Drop-In📋 Reference alternative (not in catalog)
STB140N4F8 Maximum Ratings & Electrical Characteristics
| Polarity | N-Channel |
| Drain-Source Voltage (VDS) | 40 V |
| Continuous Drain Current (ID) at 25°C | 120 A |
| Continuous Drain Current (ID) at 100°C | 85 A |
| Pulsed Drain Current (IDM) | 480 A |
| On-Resistance (RDS(on)) at VGS=10V | 4.5 mΩ (typ) |
| Gate-Source Voltage (VGS) | ±20 V |
| Gate Charge (Qg) | 60 nC (typ) |
| Input Capacitance (Ciss) | 4200 pF (typ) |
| Output Capacitance (Coss) | 700 pF (typ) |
| Reverse Transfer Capacitance (Crss) | 250 pF (typ) |
| Avalanche Energy (EAS) | 200 mJ |
| Operating Junction Temperature | -55°C to +175°C |
| Package | D2PAK (TO-263) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Halogen Free | Yes |
| ESD Rating (HBM) | 2 kV |
STB140N4F8 Pin Configuration
| Pin 1 | Gate — Gate terminal for controlling the MOSFET |
| Pin 2 | Drain — Drain terminal, connected to the tab |
| Pin 3 | Source — Source terminal |
| Pin 4 | Drain (tab) — Exposed pad connected to drain |
Safe Operating Area
Typical Applications
STB140N4F8 is suitable for 6 applications: DC-DC Converters, Motor Control, Power Supplies, Battery Management Systems, Automotive Electric Power Steering, LED Lighting.
DC-DC Converters
The STB140N4F8 is used as a synchronous rectifier in DC-DC converters. Its low RDS(on) of 4.5mΩ minimizes conduction losses, improving efficiency. In a typical buck converter, the MOSFET is placed in the low-side position, switching at frequencies up to 500kHz. The low gate charge (60nC) allows fast switching, reducing switching losses. For a 12V to 5V conversion at 20A, the power dissipation is approximately 1.8W, requiring adequate copper area for heat dissipation. Compared to Schottky diodes, the MOSFET reduces forward voltage drop, increasing overall efficiency by 2-3%.
Recommended
Motor Control
In motor control applications, the STB140N4F8 is used in the H-bridge or three-phase inverter stages. Its high current capability (120A) and avalanche ruggedness (200mJ) make it suitable for driving inductive loads. The MOSFET's fast switching reduces electromagnetic interference, and its low RDS(on) minimizes heat generation. For a brushless DC motor with 30A phase current, the MOSFET dissipates about 4W, requiring a heatsink. The device's wide temperature range (-55°C to +175°C) ensures reliable operation in automotive and industrial environments.
Recommended
Power Supplies
The STB140N4F8 is used in switch-mode power supplies (SMPS) for primary-side switching and synchronous rectification. Its low RDS(on) and high current rating enable high-efficiency designs. In a 500W server power supply, the MOSFET operates at 100kHz, with a duty cycle of 50%. The low gate charge reduces driver losses, and the low thermal resistance (0.5°C/W) allows compact heatsinking. The device's ESD rating (2kV HBM) improves manufacturing yield.
Recommended
Battery Management Systems
In battery management systems (BMS), the STB140N4F8 is used for cell balancing and protection circuits. Its low RDS(on) minimizes power loss during balancing, and its high current capability handles short-circuit conditions. The MOSFET's avalanche rating ensures robustness during inductive spikes. For a 48V battery pack, the MOSFET is placed in series with the load, controlled by a BMS IC. The device's wide temperature range is essential for outdoor and automotive battery packs.
Recommended
Automotive Electric Power Steering
The STB140N4F8 is used in electric power steering (EPS) systems to drive the steering assist motor. Its high current capability (120A) and low RDS(on) ensure efficient power delivery. The device's AEC-Q101 qualification (if applicable) and wide temperature range make it suitable for under-hood environments. In a typical EPS system, the MOSFET is part of a three-phase inverter, switching at 20kHz. The low gate charge reduces switching losses, and the robust avalanche rating handles motor back-EMF.
Recommended
LED Lighting
In LED lighting, the STB140N4F8 is used in high-power LED drivers for dimming and switching. Its low RDS(on) reduces power loss, and its high current capability supports multiple LED strings. The MOSFET's fast switching enables PWM dimming at high frequencies without audible noise. For a 100W LED driver, the MOSFET dissipates about 2W, requiring minimal heatsinking. The device's compact D2PAK package is suitable for space-constrained lighting fixtures.
Recommended
Recommended Products Summary
Engineering reference data for STB140N4F8 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STB120N4F6 | IPB120N04S4-02 | IRF1404 |
|---|---|---|---|---|
| Package | D2PAK (TO-263) | D2PAK (TO-263) | D2PAK (TO-263) | D2PAK (TO-263) |
| Brand | STMicroelectronics | STMicroelectronics | Infineon | Infineon |
| VDS (V) | 40 | 40 | 40 | 40 |
| ID at 25°C (A) | 120 | 100 | 120 | 162 |
| RDS(on) (mΩ) | 4.5 | 6.0 | 4.5 | 5.5 |
| Qg (nC) | 60 | 50 | 65 | 110 |
| EAS (mJ) | 200 | 150 | 200 | 200 |
| Operating Temp (°C) | -55 to +175 | -55 to +175 | -55 to +175 | -55 to +175 |
Key Differentiators
- Lower on-resistance than STB120N4F6 (vs STB120N4F6)
- Higher current rating than STB120N4F6 (vs STB120N4F6)
- Lower gate charge than IRF1404 (vs IRF1404)
Design Notes
At 120A continuous current, the power dissipation is I²R = 120² × 0.0045 = 64.8W. With a junction-to-case thermal resistance of 0.5°C/W, the case temperature must be kept below 175°C - 64.8×0.5 = 142.6°C. Use a heatsink with thermal resistance less than (142.6 - ambient)/64.8. For 25°C ambient, heatsink Rth must be < 1.8°C/W. Ensure adequate airflow or liquid cooling for high-current applications.
For D2PAK, the exposed pad is the drain. Solder the pad to a large copper area with multiple thermal vias to improve heat dissipation. Use a minimum of 4 vias with 0.3mm diameter under the pad. Keep the gate trace short and away from high-current paths to reduce parasitic inductance. Place a 10Ω gate resistor to dampen oscillations.
Do not exceed the maximum VGS of ±20V. Use a gate driver with proper voltage clamping. Avoid operating in the linear region for extended periods; the MOSFET is designed for switching. Ensure the avalanche energy rating is not exceeded during unclamped inductive switching; add a snubber if necessary.
Compliance Information
RoHS compliant and halogen-free per STMicroelectronics product page. Not AEC-Q100 qualified; for automotive, check if AEC-Q101 version is available.