STU75N3LLH6 Equivalent & Substitute Parts

Part Overview

The STU75N3LLH6 is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 30V drain-to-source voltage and 75A continuous drain current. This device is housed in a TO-251 (IPAK) through-hole package and is designed for general-purpose switching and power conversion applications. The part is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design support and procurement.

Substiute Parts

STU75N3LLH6

STMicroelectronicsIn Stock: 15477STU75N3LLH6 Datasheet

Current PartRFQ

IRFU7440PBF

Infineon TechnologiesIn Stock: 20350IRFU7440PBF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the STU75N3LLH6 is determined by the following critical parameters:

Electrical Compatibility Criteria:

• FET Type: N-Channel topology must be maintained
• Drain to Source Voltage (Vdss): Substitute must equal or exceed 30V rating
• Continuous Drain Current (Id): Substitute must equal or exceed 75A at 25°C
• On-State Resistance (Rds On): Lower or equivalent values ensure thermal performance
• Power Dissipation: Substitute must support thermal requirements of the application
• Gate Voltage (Vgs): Maximum rating must accommodate driver circuit specifications

Mechanical Compatibility Criteria:

• Mounting Type: Through-hole configuration required
• Package / Case: TO-251 (IPAK) form factor with compatible pinout

Regulatory Compliance:

• RoHS3 compliance required for environmental standards
• Operating temperature range: -55°C to 175°C minimum

The IRFU7440PBF meets these substitution criteria with higher voltage and current ratings, lower on-state resistance, and identical package configuration.

Parameter Comparison

Engineering Selection Recommendations

The IRFU7440PBF is a direct substitute for the STU75N3LLH6 based on the following engineering criteria:

Electrical Performance: The IRFU7440PBF exceeds the electrical specifications of the STU75N3LLH6 across all critical parameters. The 40V Vdss rating provides 33% higher voltage margin, the 90A continuous drain current exceeds the 75A requirement by 20%, and the 2.4 mOhm on-state resistance is 59% lower than the 5.9 mOhm specification. These improvements result in reduced power dissipation and enhanced thermal performance in equivalent circuit topologies.

Package Compatibility: Both devices utilize the TO-251 (IPAK) through-hole package with identical pinout configuration, enabling direct mechanical and electrical substitution without circuit board modifications.

Regulatory Compliance: Both parts maintain ROHS3 compliance and operate across the identical temperature range of -55°C to 175°C, satisfying environmental and thermal design requirements.

Availability and Status: Both devices are classified as obsolete. The IRFU7440PBF maintains higher inventory availability (20,300 pieces) compared to the STU75N3LLH6 (15,465 pieces), supporting procurement continuity.

Frequently Asked Questions (FAQ)

Q: Can the IRFU7440PBF directly replace the STU75N3LLH6 without circuit modifications?

A: Yes. Both devices share identical TO-251 (IPAK) package geometry and pinout configuration. The IRFU7440PBF meets or exceeds all electrical specifications of the STU75N3LLH6, including gate voltage ratings (±20V), operating temperature range (-55°C to 175°C), and RoHS3 compliance. No circuit board layout changes are required.

Q: What are the key electrical differences between these parts?

A: The IRFU7440PBF provides higher voltage and current ratings: 40V Vdss versus 30V, 90A continuous drain current versus 75A, and significantly lower on-state resistance of 2.4 mOhm versus 5.9 mOhm at 10V gate voltage. Power dissipation capability is 140W versus 60W. These improvements enhance performance in switching applications while maintaining backward compatibility.

Q: Are both parts suitable for the same application circuits?

A: Yes. Both devices are N-Channel MOSFETs with identical gate voltage specifications (±20V maximum) and operating temperature ranges. Applications designed for the STU75N3LLH6 operate within the electrical envelope of the IRFU7440PBF. The superior specifications of the IRFU7440PBF provide design margin and improved thermal performance.

Q: What is the significance of the lower on-state resistance in the IRFU7440PBF?

A: Lower on-state resistance (Rds On) reduces conduction losses during switching operation. The IRFU7440PBF's 2.4 mOhm specification versus the STU75N3LLH6's 5.9 mOhm results in lower heat generation, reduced power dissipation, and improved efficiency in power conversion circuits. This is particularly beneficial in high-frequency switching applications.

Q: Are there any gate charge differences that affect driver circuit design?

A: Yes. The IRFU7440PBF has a gate charge (Qg) of 134 nC at 10V, compared to 23.8 nC for the STU75N3LLH6. This higher gate charge requires slightly more driver current to achieve the same switching speed. Existing gate driver circuits designed for the STU75N3LLH6 remain compatible but may exhibit slightly slower switching transitions with the IRFU7440PBF.

Q: Do both parts have identical moisture sensitivity and handling requirements?

A: Yes. Both devices are rated MSL 1 (Unlimited moisture sensitivity level), indicating no moisture-related handling restrictions during storage or assembly. Both are REACH Unaffected and classified under ECCN EAR99 for export purposes.

Q: What inventory considerations apply to these obsolete parts?

A: Both devices are classified as obsolete. The IRFU7440PBF has higher current inventory (20,300 pieces) versus the STU75N3LLH6 (15,465 pieces). For new designs or long-term production requirements, the IRFU7440PBF offers better procurement availability and supply continuity.