IRFZ44N IR series MOSFET
Without a doubt, transistors are one of the essential active electronic component types. Although there are innumerable transistors on the market, there are basically just two types. Many engineers have their preferred type; however, there are notable differences between bipolar junction transistors (BJTs) and field-effect transistors (FETs). A major difference between BJTs and FETs is how they are controlled or turned off and on. BJTs are current-controlled, similar to their predecessors, vacuum tubes, while FETs are controlled by applying voltage to the gate. BJTs are also typically larger and have higher gain than FETs. And, although cheaper than FETs, BJTs are less often implemented. Among FETs, which includes junction field effect transistors (JFETs) and metal-oxide field effect transistors (MOSFETS), MOSFETs are considered better suited for most applications. This is due to their high input impedance and high drain resistance. Infineon Technologies is a well-known manufacturer of these devices, like the IRLZ44N and IRFZ44N, which fall under their IR series of MOSFETs. Making the best use of the latter requires that you utilize the IRFZ44N datasheet and readily available CAD design data.Features and Applications of IR Series MOSFETs
The IRFZ44N is one of a series of Infineon MOSFETs, which are defined primarily by the characteristics listed below.| MOSFET SERIES PARAMETRIC COMPARISON | |||||
| Parameter | IRFZ44N | IRFZ44NPBF | IRF540N | IRFP250N | STP55NF06 |
| Drain-Source Voltage (VDS) | 55V | 55V | 100V | 200V | 60V |
| Continuous Drain Current (ID) | 49A | 49A | 33A | 30A | 55A |
| Gate-Source Voltage (VGS) | ±20V | ±20V | ±20V | ±20V | ±20V |
| On-Resistance (RDS(on)) | 17.5mΩ | 17.5mΩ | 44mΩ | 85mΩ | 14mΩ |
| Gate Threshold Voltage | 2-4V | 2-4V | 2-4V | 2-4V | 1-2.5V |
| Power Dissipation (PD) | 94W | 94W | 125W | 190W | 110W |
| Package Type | TO-220 | TO-220AB | TO-220AB | TO-247AC | TO-220 |
| Price Range (1K qty) | $0.45-0.65 | $0.50-0.70 | $0.35-0.55 | $1.20-1.80 | $0.40-0.60 |
These devices share the following attributes:
IR Series MOSFET Features
The IRFZ44NPbF, in particular, has the following attributes:
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These high power amplifiers are commonly used in such varied applications as load switches, lighting systems, switch-mode power supplies, inverters, and DC motors. Important specifications are presented below.
Important IRFZ44N Specifications
The IRFZ44N has been on the market for decades. This is due to its favorable device parameters, which are found in the IRFZ44N datasheet, and shown below.
Below are the electrical characteristics for deployment in an ambient environment.
IRFZ44N Operational Attributes
As the IRFZ44N datasheet illustrates, the amplifier output characteristic remains constant over a wide range of currents..
To protect the device and ensure safe operation, the limits exhibited below should be observed.
IRFZ44N safe operation range
Common Applications and Circuit Examples
The IRFZ44N is often used in DC motor, Switch-Mode Power Supply (SMPS), LED driver, and automotive system PCB design applications, as described below.
High-Current DC Motor Control
The IRFZ44N excels in DC motor control applications up to 3HP (2.2kW) with proper heat sinking. The low gate threshold voltage enables direct control from 5V microcontroller outputs through a simple gate driver circuit.
Design Considerations:
- Flyback Diode: Always include a fast recovery diode (such as UF4007) across the motor terminals
- Gate Drive: Use a 100Ω gate resistor to limit switching transients while maintaining fast switching
- Heat Sinking: Calculate thermal resistance based on worst-case operating conditions and ambient temperature
Switch-Mode Power Supply Applications
In forward converter and synchronous buck converter topologies, the IRFZ44N serves effectively as both primary and synchronous rectifier switches for power levels up to 500W.
| Power Level | Switching Frequency | Heat Sink Requirement | Efficiency Range |
| 0-100W | Up to 100kHz | Optional | 92-95% |
| 100-300W | 50-75kHz | Required | 90-93% |
| 300-500W | 25-50kHz | Large heat sink | 88-91% |
LED Driver Circuits
For high-power LED applications, the IRFZ44N provides precise current control through source-follower configuration or PWM switching. The low on-resistance minimizes power dissipation in constant-current applications.
PWM Dimming Performance:
- Frequency Range: Effective operation from 100Hz to 20kHz
- Duty Cycle Range: 1% to 99% with linear brightness control
- Current Ripple: Less than 5% with proper inductor selection
Automotive Applications
The IRFZ44N meets automotive requirements for 12V systems but requires careful thermal design for under-hood installations. The 55V voltage rating provides adequate margin for load dump conditions with proper TVS protection.
Automotive-Specific Considerations:
- Temperature Range: Derate current above 85°C ambient
- EMI Compliance: Add snubber circuits for switching noise suppression
- Protection: Include overcurrent sensing and thermal shutdown
Alternatives to the IRFZ44N
With today’s supply chain volatility, it is not just advisable, but essential to include alternative components when building or modifying your component library. For some components, a number of characteristics can be used to compile viable alternatives and equivalents; such as pin number and configuration, performance, and/or cost.
Pin-Compatible Equivalents
IRFZ44NPBF (Lead-Free Version)
The IRFZ44NPBF offers identical electrical specifications with RoHS compliance. This direct replacement requires no circuit modifications and provides the same thermal characteristics. Choose this variant for new designs requiring lead-free compliance or when IRFZ44N availability is limited.
STP55NF06 (STMicroelectronics)
This alternative provides a 12% higher continuous current rating (55A vs 49A) with 20% lower on-resistance (14mΩ vs 17.5mΩ). The improved specifications come with a 10-15% price premium but deliver better efficiency in high-current applications.
Performance-Optimized Alternatives
| POWER MOSFET COMPARISON | |||
| Component | Key Advantage | Trade-offs | Best Applications |
| IRF540N | Higher voltage rating (100V) | Higher RDS(on) (44mΩ) | Motor drives, automotive |
| IRFP250N | Ultra-high voltage (200V) | Lower current (30A), higher cost | Industrial switching |
| IRLB8721 | Logic-level gate (2.5V) | Lower voltage rating (30V) | Microcontroller interfacing |
| IRFP4468 | Extreme current (195A) | Much higher cost, TO-247 package | Welding, high-power supplies |
Cost-Optimized Substitutes
IRF540N
Provides 82% of IRFZ44N current capability with a 100V voltage rating at 20% lower cost. Suitable when the higher voltage rating compensates for reduced current handling.
IRLZ44N
Logic-level version enabling direct microcontroller drive without gate driver circuits. The 2.5V gate threshold reduces system complexity in digital control applications.
When opting for an alternative or parametric-equivalent component, it is often necessary to perform significant redesign. To avoid this time-consuming and costly endeavor, it is best to devise a selection criterion.
How to Choose IRFZ44N Alternatives
Ensure that equivalents have the following characteristics:
- Current Requirements: 25-45A continuous operation
- Voltage Requirements: 12-48V DC systems
- Cost Sensitivity: Budget-conscious designs
- Thermal Constraints: Adequate heat sinking available
Optimal Design Using the IRFZ44N Datasheet
There are several benefits to utilizing the IRFZ44N, as its longevity and usage attest to. However, for the best design, the IRFZ44N datasheet should be supported with sound and accurate CAD drawings, as shown below, and simulation and testing information available at the UL online library.
If you’re looking for CAD models and/or design data for common components like the IRFZ44N datasheet, Ultra Librarian helps by compiling all your sourcing and CAD information in one place.
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