IRLU120PBF N-Channel MOSFET 100V 7.7A TO-251AA Equivalent & Substitute Parts

Part Overview

The IRLU120PBF is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 100V drain-to-source voltage and 7.7A continuous drain current in a TO-251AA (IPAK) through-hole package. This device is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing production support, design updates, and component sourcing.

The IRLU120PBF operates across a temperature range of -55°C to 150°C and dissipates up to 2.5W at ambient temperature or 42W at case temperature. Its primary application domain includes switching circuits, power management, and general-purpose MOSFET switching applications requiring moderate voltage and current ratings.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	100	V
Continuous Drain Current (Id) @ 25°C	7.7	A (Tc)
On-State Resistance (Rds On) @ 4.6A, 5V	270	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	2	V
Gate Charge (Qg) @ 5V	12	nC
Input Capacitance (Ciss) @ 25V	490	pF
Power Dissipation (Max)	2.5 (Ta), 42 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-251AA (IPAK)	Through Hole
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the IRLU120PBF is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 100V
Continuous Drain Current (Id): Must equal or exceed 7.7A
Package Type: Must be TO-251AA (IPAK) through-hole for direct mechanical compatibility
Gate Threshold Voltage (Vgs(th)): Must be compatible with existing gate drive circuits
On-State Resistance (Rds On): Lower values indicate improved performance; higher values require thermal evaluation
Operating Temperature Range: Must support -55°C to 150°C minimum
RoHS Compliance: Must maintain ROHS3 compliance for regulatory continuity

Substitute Categories:

Category 1: Direct Pin-Compatible Substitutes (Same Package, Same Voltage Class) Parts that maintain identical TO-251AA packaging and 100V voltage rating with equal or superior current ratings and thermal performance.

Category 2: Enhanced Performance Substitutes (Same Package, Higher Voltage Rating) Parts that maintain TO-251AA packaging but offer higher voltage ratings, providing design margin and broader application flexibility.

Category 3: Lower Current Substitutes (Same Package, Same Voltage) Parts that maintain TO-251AA packaging and 100V voltage rating but with reduced current ratings, suitable for applications with lower current requirements.

Parameter Comparison

Parameter	IRLU120PBF (Main)	IRLU120NPBF	IRFU120NPBF	STU6NF10	IRL630PBF
Manufacturer	Vishay Siliconix	Infineon Technologies	Infineon Technologies	STMicroelectronics	Vishay Siliconix
Vdss (V)	100	100	100	100	200
Id @ 25°C (A)	7.7	10	9.4	6	9
Rds On (mOhm)	270 @ 4.6A, 5V	185 @ 6A, 10V	210 @ 5.6A, 10V	250 @ 3A, 10V	400 @ 5.4A, 5V
Vgs(th) (V)	2 @ 250µA	2 @ 250µA	4 @ 250µA	4 @ 250µA	2 @ 250µA
Qg (nC)	12 @ 5V	20 @ 5V	25 @ 10V	14 @ 10V	40 @ 10V
Ciss (pF)	490 @ 25V	440 @ 25V	330 @ 25V	280 @ 25V	1100 @ 25V
Power Dissipation (W)	2.5 (Ta), 42 (Tc)	48 (Tc)	48 (Tc)	30 (Tc)	74 (Tc)
Operating Temp (°C)	-55 to 150	-55 to 175	-55 to 175	-65 to 175	-55 to 150
Package	TO-251AA	TO-251AA	TO-251AA	TO-251 (IPAK)	TO-220AB
Product Status	Obsolete	Not For New Designs	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

IRLU120NPBF (Infineon Technologies)

The IRLU120NPBF is a direct package-compatible substitute with identical TO-251AA packaging and 100V voltage rating. It provides superior current rating (10A vs. 7.7A) and improved on-state resistance (185mOhm vs. 270mOhm), resulting in lower power dissipation and improved thermal performance. The device maintains gate threshold voltage compatibility (2V) with the original part. However, the IRLU120NPBF carries a "Not For New Designs" product status, limiting its suitability for new development projects. This part is appropriate for legacy system maintenance and direct replacement in existing designs.

IRFU120NPBF (Infineon Technologies)

The IRFU120NPBF maintains TO-251AA packaging and 100V voltage rating with 9.4A continuous drain current, exceeding the original 7.7A specification. This part is classified as Active product status, making it suitable for new designs and long-term production support. The IRFU120NPBF exhibits improved on-state resistance (210mOhm) and lower input capacitance (330pF vs. 490pF), enabling faster switching characteristics. Gate threshold voltage is elevated to 4V, requiring verification of gate drive circuit compatibility. Operating temperature range extends to 175°C, providing enhanced thermal margin. This part is recommended for new designs requiring direct TO-251AA package compatibility.

STU6NF10 (STMicroelectronics)

The STU6NF10 maintains TO-251 (IPAK) packaging and 100V voltage rating with 6A continuous drain current, below the original 7.7A specification. This part is classified as Active product status. The STU6NF10 exhibits on-state resistance of 250mOhm and the lowest input capacitance (280pF) among all substitutes, enabling superior switching speed. Gate threshold voltage is 4V. Operating temperature range extends to 175°C. This part is suitable for applications where current requirements are 6A or lower and switching speed optimization is prioritized.

IRL630PBF (Vishay Siliconix)

The IRL630PBF differs significantly from the original part by offering 200V drain-to-source voltage in a TO-220AB package. This part is not pin-compatible with the IRLU120PBF due to different package geometry (TO-220AB vs. TO-251AA). The IRL630PBF provides 9A continuous drain current and 74W power dissipation at case temperature, representing substantial thermal capability. This part is classified as Active product status. The IRL630PBF is suitable only for applications where PCB layout can accommodate TO-220AB package dimensions and where the higher voltage rating provides design benefit. Direct substitution without PCB redesign is not possible.

Frequently Asked Questions (FAQ)

Q: Can the IRLU120NPBF directly replace the IRLU120PBF without PCB modifications?

A: Yes. Both parts use identical TO-251AA (IPAK) through-hole packaging with the same pin configuration and footprint. No PCB layout changes are required for mechanical compatibility. However, the IRLU120NPBF carries "Not For New Designs" status, limiting its use to legacy system support.

Q: Is the IRFU120NPBF suitable for new product designs?

A: Yes. The IRFU120NPBF is classified as Active product status and maintains TO-251AA package compatibility with the original IRLU120PBF. The elevated gate threshold voltage (4V vs. 2V) requires verification that existing gate drive circuits can reliably turn the device on and off. All other electrical parameters are compatible or superior.

Q: What is the primary difference between the STU6NF10 and the original IRLU120PBF?

A: The STU6NF10 has a lower continuous drain current rating (6A vs. 7.7A) and higher gate threshold voltage (4V vs. 2V). It offers superior switching speed due to lower input capacitance (280pF vs. 490pF). This part is suitable for applications with current requirements of 6A or lower.

Q: Why is the IRL630PBF not a direct substitute?

A: The IRL630PBF uses TO-220AB package geometry, which differs from the TO-251AA package of the IRLU120PBF. The pin spacing, lead length, and mounting hole pattern are incompatible with existing PCB designs. PCB redesign is required for mechanical integration. Additionally, the higher voltage rating (200V vs. 100V) may introduce unnecessary design complexity.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (IRLU120NPBF, IRFU120NPBF, STU6NF10, and IRL630PBF) maintain ROHS3 compliance, ensuring regulatory continuity with the original IRLU120PBF.

Q: What is the impact of different gate threshold voltages on circuit operation?

A: Gate threshold voltage (Vgs(th)) determines the minimum gate-to-source voltage required to turn the MOSFET on. The original IRLU120PBF has Vgs(th) of 2V, while IRFU120NPBF and STU6NF10 have 4V. If gate drive circuits are designed for 2V threshold, parts with 4V threshold may not turn on reliably at low gate voltages. Gate drive circuit verification is required before substitution.

Q: Which substitute part offers the best thermal performance?

A: The IRL630PBF offers the highest power dissipation capability (74W at case temperature) due to its TO-220AB package, which provides superior thermal coupling to PCB and heatsinks. Among TO-251AA package options, the IRLU120NPBF and IRFU120NPBF both provide 48W dissipation, compared to 42W for the original IRLU120PBF.

Q: Can the STU6NF10 be used in applications requiring 7.7A continuous current?

A: No. The STU6NF10 is rated for 6A continuous drain current, which is below the 7.7A requirement. Using this part in applications exceeding 6A will result in device overheating and potential failure. Current requirements must be verified before substitution.

Q: What is the difference between "Active" and "Not For New Designs" product status?

A: "Active" status indicates the manufacturer continues production and provides long-term supply commitment, making these parts suitable for new product designs. "Not For New Designs" status indicates the manufacturer is phasing out the part and recommends alternative solutions for new projects, though existing inventory may remain available for legacy support.

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