Transistor IRF730: Specifications, Pinout, Equivalent

According to the technical specifications, IRF730 is a powerful N-channel MOSFET transistor with a silicon-insulated gate and an internal diode. It is developed by International Rectifier (IR) using their proprietary HEXFET technology. It is commonly used in pulse power supplies, various converters, motor control circuits, and high-speed power switching circuits with a voltage rating (VDS) up to 400V and a current rating (ID) up to 5.5A


The IRF730 is available in a TO-220 package and its various modifications, designed to meet modern requirements. The pinout arrangement from left to right is as follows: Pin 1 – Gate (G), Pin 2 – Source (S), Pin 3 – Drain (D). The device’s structure and pinout are visually represented in the image below.


Modern products feature packages manufactured using lead-free (Pb-Free) technologies and comply with European RoHS environmental standards.

Max Specifications of IRF730:

  • On-state resistance (RDS(on)) up to 1.0 Ohm;
  • Recovery diode pulse (dv/dt) up to 4.6 V/ns;
  • Drain current: continuous (ID): 5.5A (at +25°C), up to 3.5A (at +100°C);
  • Peak drain current (IDM) up to 22A, avalanche condition (IAR) up to 5.5A;
  • Power dissipation (PD) up to 74W (with a heat sink);
  • Voltage between pins: S-D (VDS) up to 400V, G-S (VGS) up to ±30V;
  • Operating junction (TJ) and storage (TSTG) temperature from -55°C to +150°C.

The listed parameters are the maximum ratings for the considered MOSFET. Any simultaneous, even minor and momentary, exceedance of two or more characteristic values can lead to crystal and package overheating and cause device failure.

It should be noted that some manufacturers specify a maximum power dissipation (PD) for devices in a TO-220 package not exceeding 50W in their technical datasheets.


The main feature and primary advantage of the IRF730 MOSFET transistor is its relatively low on-state resistance (RDS(on)). With proper cooling (at TJ = +25°C), it does not exceed 1 Ohm, and for some manufacturers, it is even less, not exceeding 0.75 Ohms. This RDS(on) value is typical for most devices developed using IR’s HEXFET technology.

Unfortunately, during the device’s operation, the value of RDS(on) increases due to the temperature rise of the crystal and the surrounding environment. Under severe heating (over TJ = +100°C), the RDS(on) value can reach 1.7 Ohms and higher.

To prevent overheating issues and achieve stable operation of powerful power transistors, the manufacturer allows for passive cooling. For the IRF730, a metal substrate with a special screw hole is available for this purpose. Mounting it on a heat sink should be done using a mica insulating washer.


The full equivalent of IRF730 is the SiHF730 MOSFET transistor from Vishay Siliconix. As alternatives, the following can also be recommended: IRF720, SiHF720, IRF740, SiHF740, STP7NK40Z, Si9933, HAT1024R, STS3DPF20V, HAT3004, STP7NK40Z, STS5DNF20V, FDS9936A, HAT2016R.


To access the datasheet for IRF730, you can follow the corresponding link from the manufacturer’s name. The main manufacturers include:

  • First Components International;
  • Fairchild;
  • First Silicon;
  • NXP Semiconductors;
  • Dc Components;
  • Intersil Corporation;
  • New Jersey Semi-Conductor Products;
  • Suntac Electronic;
  • ST Microelectronics;
  • Advanced Power Electronics.
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