IRFZ44NPBF - 55V 49A N-Channel HEXFET MOSFET | Infineon
MPN: IRFZ44NPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.62 | $1.62 |
| 10 | $1.42 | $14.20 |
| 100 | $1.18 | $118.00 |
| 500 | $0.96 | $480.00 |
| 1,000 | $0.78 | $780.00 |
| 3,000 | $0.65 | $1,950.00 |
IRFZ44NPBF Overview
A power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a voltage-controlled semiconductor switch used to efficiently switch and amplify electronic signals in power conversion circuits. N-channel MOSFETs like the IRFZ44NPBF are the dominant switch topology in synchronous rectification, DC-DC converters, and motor drive stages because electron mobility in N-channel silicon gives lower RDS(on) per die area than equivalent P-channel devices. The IRFZ44NPBF belongs to the broader hierarchy of discrete semiconductors (MOSFET > power MOSFET > N-channel MOSFET > enhancement-mode MOSFET).
Key features include advanced HEXFET process technology, avalanche energy rating (EAS) for unclamped inductive switching, low thermal resistance junction-to-case of 1.0 C/W, and a logic-level compatible gate threshold range of 1V to 3V (typical VGS(th) around 2V). The TO-220AB package provides a robust mechanical form factor with a metal tab that doubles as the drain terminal and a heatsink mounting surface, making the part well-suited for both through-hole PCB designs and chassis-mounted heatsink assemblies.
Architecturally, the IRFZ44NPBF uses Infineon's planar HEXFET cell structure with vertical current flow between top-side source bond wires and the bottom-side drain tab. This vertical DMOS architecture delivers very low specific on-resistance, enabling the 17.5 mOhm figure at 49A continuous rating. The fast switching speed supports frequencies from DC to over 1 MHz when paired with a proper gate driver, and the ruggedized design tolerates avalanche energy events typical of motor and solenoid loads.
Typical applications include SMPS (switched-mode power supply) primary-side switching, DC motor drive H-bridges (low-side position), solenoid and relay drivers, audio amplifier output stages, and Class-D amplifier power switches. Its 49A continuous rating comfortably handles 20-30A continuous loads with adequate heatsinking.
When designing with this device, select a gate driver that can source/sink at least 1A peak to achieve sub-100ns switching transitions. For switching frequencies above 100 kHz, a dedicated gate driver IC such as the IR2110 or UCC27211 is recommended over direct MCU GPIO drive to minimize switching losses and prevent thermal runaway.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that supplement the manufacturer datasheet to help engineers evaluate the IRFZ44NPBF for new designs and second-source qualification.
Drop-in alternatives for IRFZ44NPBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with IRFZ44NPBF (same form factor and footprint) — differing in Technology, Package, Total Gate Charge (Qg), RoHS Status, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
IRFZ44NSTRLPBF
✅ Drop-In✓ In Stock
$0.93 / Unit
View Datasheet →IRLZ44NPBF
✅ Drop-In✓ In Stock
$0.6779 / Unit
View Datasheet →IRF5210PBF
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →STP55NF06L
✅ Drop-In📋 Reference alternative (not in catalog)
FQP55N06
✅ Drop-In📋 Reference alternative (not in catalog)
IRFZ46N
✅ Drop-In📋 Reference alternative (not in catalog)
IRFZ44NPBF Maximum Ratings & Electrical Characteristics
| FET Type | N-Channel |
| Drain-to-Source Voltage (VDS) | 55 V |
| Continuous Drain Current (ID) at Tc=25C | 49 A |
| Gate-to-Source Voltage (VGS) max | +/- 20 V |
| Static Drain-Source On-Resistance (RDS(on)) at VGS=10V | 17.5 mOhm |
| Total Gate Charge (Qg) | 42 nC |
| Power Dissipation (PD) at Tc=25C | 94 W |
| Thermal Resistance Junction-to-Case (RthJC) | 1.0 C/W |
| Thermal Resistance Junction-to-Ambient (RthJA) | 62 C/W |
| Operating Junction Temperature | -55C to +175C |
| Package | TO-220AB (3-pin + tab) |
| Mounting Type | Through Hole |
| Technology | HEXFET (Advanced Process) |
| RoHS Status | Compliant |
IRFZ44NPBF Pin Configuration
| Pin 1 | Gate (G) — Gate control input; VGS=10V required for full enhancement |
| Pin 2 | Drain (D) — Main current terminal; also connected to metal tab |
| Pin 3 | Source (S) — Return terminal for drain current |
| Pin TAB | Drain (D) — Metal tab electrically and thermally connected to Drain (Pin 2) |
Safe Operating Area - DC Continuous
Typical Applications
IRFZ44NPBF is suitable for 6 applications: Switched-Mode Power Supply (SMPS) Primary-Side Switch, DC Motor Drive H-Bridge Low-Side Switch, Automotive Relay and Solenoid Driver, Class-D Audio Amplifier Output Switch, Battery Protection and Load Switching, Inductive Heating and Welding Power Stage.
Switched-Mode Power Supply (SMPS) Primary-Side Switch
The IRFZ44NPBF is well-suited as the main primary-side switch in 24V-48V input SMPS topologies including forward, push-pull, and half-bridge converters up to 500 W. Its 17.5 mOhm RDS(on) at VGS=10V keeps conduction losses below 1% at 20 A continuous, and the 94 W power dissipation rating provides ample thermal margin for sustained operation. The 55 V VDS rating safely covers 36 V-48V telecom bus rails with adequate avalanche margin for transformer leakage energy. Use a gate driver IC (such as IR2114SSPBF) to source/sink 1A peak gate current for switching frequencies of 100 kHz-500 kHz, minimizing crossover losses in the linear region.
Recommended
DC Motor Drive H-Bridge Low-Side Switch
In brushed DC motor H-bridge configurations, the IRFZ44NPBF serves as the low-side switch with continuous current capability up to 49 A at Tc=25C, comfortably handling 20-30A motor loads common in robotics, e-bikes, and power tools. The 42 nC total gate charge keeps gate driver losses manageable at PWM frequencies up to 50 kHz, and the 175C maximum junction temperature provides thermal headroom under stall conditions. Pair with a P-channel or N-channel high-side switch (such as IRF5210PBF) and a dedicated gate driver to prevent shoot-through. The TO-220AB package mounts directly to a chassis heatsink for continuous-duty motor control applications.
Recommended
Automotive Relay and Solenoid Driver
The IRFZ44NPBF is rated for 49A continuous drain current with avalanche energy capability, making it suitable for driving automotive solenoids, relays, and inductive actuators directly from 12V or 24V vehicle buses. The 55V VDS rating exceeds the ISO 7637-2 load-dump transient requirement of 35V, providing robust transient suppression when paired with a TVS clamp. Its low 17.5 mOhm RDS(on) reduces voltage drop across the switch, ensuring full coil voltage reaches the load. Use a flyback diode or RCD snubber across inductive loads to clamp drain voltage spikes within the 55V maximum rating during switch-off.
Recommended
Class-D Audio Amplifier Output Switch
The IRFZ44NPBF can be used in the output stage of Class-D audio amplifiers rated up to 200 W per channel, where its 17.5 mOhm RDS(on) and fast switching characteristics minimize distortion and thermal losses. The 42 nC total gate charge supports switching frequencies of 250 kHz-500 kHz typical for Class-D amplifiers, well above the audio band. For a balanced design, pair with a complementary P-channel device on the high side or use a half-bridge topology with a gate driver such as IRS2011STRPBF or IR21834STRPBF. The TO-220AB package allows direct mounting to the amplifier chassis for effective thermal management.
Recommended
Battery Protection and Load Switching
In 12V-48V battery management systems, the IRFZ44NPBF can serve as the main load disconnect switch or reverse-polarity protection element, leveraging its 49A continuous current rating to handle high inrush currents from capacitive loads. The low RDS(on) of 17.5 mOhm minimizes voltage drop and self-heating, preserving battery runtime in portable applications. The 55V VDS rating safely handles 48V nominal battery systems with transient margin. For full battery protection, combine with a battery monitor IC and consider a back-to-back N-channel configuration to block bidirectional current flow.
Recommended
Inductive Heating and Welding Power Stage
The IRFZ44NPBF is suited for low-frequency induction heating and small welding power supplies operating from 24V-48V DC bus inputs. Its 94 W power dissipation and 1.0 C/W junction-to-case thermal resistance enable sustained high-current pulses for heating coils, while the 55V VDS rating tolerates the inductive kickback from poorly-coupled loads. The HEXFET process technology provides rugged avalanche energy capability for the harsh switching environment of resonant tank circuits. Use a gate driver with sufficient peak current (1A or more) to fully enhance the MOSFET within the resonant cycle for maximum efficiency.
Recommended
Recommended Products Summary
Engineering reference data for IRFZ44NPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | IRFZ44NSTRLPBF | IRLZ44NPBF | STP55NF06L | FQP55N06 |
|---|---|---|---|---|---|
| Brand | Infineon | Infineon | Infineon | STMicroelectronics | onsemi |
| Package | TO-220AB | TO-220AB - same | TO-220AB - same | TO-220AB - same | TO-220AB - same |
| Drain-to-Source Voltage (VDS) | 55 V | 55 V | 55 V | 60 V (+9%) | 60 V (+9%) |
| Continuous Drain Current (ID) | 49 A | 49 A | 47 A | 50 A (+2%) | 55 A (+12%) |
| RDS(on) at VGS=10V | 17.5 mOhm | 17.5 mOhm | 22 mOhm (+26%) | 18 mOhm (+3%) | 18 mOhm (+3%) |
| Gate Threshold Voltage (VGS(th)) | 1-3 V (typ 2V) | 1-3 V | 0.7-1.5 V (logic-level) | 1-2.5 V (logic-level) | 2-4 V |
| Total Gate Charge (Qg) | 42 nC | 42 nC | 48 nC | 55 nC | 63 nC |
| Power Dissipation (PD) at Tc=25C | 94 W | 94 W | 94 W | 100 W | 107 W |
| Logic-Level Gate Drive | No (requires VGS=10V) | No | Yes (VGS=4V) | Yes (VGS=5V) | No |
| Unit Price (qty-1, as of 2026-09-14) | $1.62 | $1.58 | $1.85 | $1.45 | $1.20 |
Key Differentiators
- Established Infineon HEXFET process technology with proven long-term reliability (vs STP55NF06L (STMicroelectronics))
- Higher current rating with comparable RDS(on) (vs FQP55N06 (onsemi))
- Lower RDS(on) compared to logic-level alternative (vs IRLZ44NPBF (Infineon logic-level))
Design Notes
Estimated: The IRFZ44NPBF has a junction-to-case thermal resistance RthJC of 1.0 C/W and junction-to-ambient RthJA of 62 C/W without heatsink. For a design dissipating 20 W at TA=40C with TJ_max=150C, the maximum allowable case-to-ambient thermal resistance is (150-40)/20 - 1.0 = 4.5 C/W, requiring a substantial heatsink. Always use thermal interface material (TIM) between the TO-220AB tab and heatsink, and consider an insulating pad if the tab (drain) is at a non-ground potential.
When using the TO-220AB package in through-hole PCB designs, provide adequate copper pour around the drain tab to spread heat to inner PCB layers. A minimum 1 square inch of 2 oz copper on the top layer connected to the drain footprint can reduce RthJA by 30-40%. For through-hole designs, keep lead lengths short and use wide traces (>=20 mil per ampere) to minimize parasitic inductance that can cause voltage overshoot during switching.
Do NOT drive the IRFZ44NPBF gate directly from a 5V microcontroller GPIO - the gate threshold VGS(th) of 1-3V means the MOSFET is barely enhanced at 5V, leading to high RDS(on) and thermal runaway. Use a dedicated gate driver IC capable of sourcing 10V-12V and 1A peak current. Also ensure VGS never exceeds +/-20V, including transient spikes from gate drive loops; add a 10k pull-down on the gate to keep the device off during MCU reset.
Minimize the gate drive loop inductance by placing the gate driver IC within 1 cm of the MOSFET gate pin. Use a wide, short gate trace (>=20 mil) and place a 10-100 ohm gate resistor in series to dampen ringing. Keep the power loop (drain to load to source to ground) separate from the gate drive loop to avoid coupling. For high-frequency switching (>100 kHz), consider using a Kelvin source connection if available, or at minimum ensure the source lead inductance is minimized in the PCB layout.
Compliance Information
RoHS compliant per Infineon datasheet PD-94787B. The PBF suffix explicitly denotes lead-free, RoHS-compliant variant. Not AEC-Q100 qualified; for automotive applications requiring AEC-Q100, consider Infineon's automotive-grade MOSFET portfolio.
