IRFR3704 Equivalent & Substitute Parts Reference

Part Overview

The IRFR3704 is an N-Channel MOSFET manufactured by Infineon Technologies, rated for 20V drain-to-source voltage and 75A continuous drain current in a surface mount DPAK package. This device is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity. Substitute parts must maintain compatibility across electrical ratings, thermal performance, and mechanical packaging to ensure direct replacement capability.

Substiute Parts

IRFR3704

Infineon TechnologiesIn Stock: 2919IRFR3704 Datasheet

Current PartRFQ

STD100N3LF3

STMicroelectronicsIn Stock: 15489STD100N3LF3 Datasheet

MFR RecommendedRFQ

STD150N3LLH6

STMicroelectronicsIn Stock: 10334STD150N3LLH6 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the IRFR3704 are identified based on the following critical parameters that determine functional equivalence:

Primary Selection Criteria:

• Drain-to-Source Voltage (Vdss): Substitute parts must equal or exceed 20V
• Continuous Drain Current (Id): Substitute parts must equal or exceed 75A at 25°C
• On-State Resistance (Rds On): Lower or equal values ensure thermal performance compatibility
• Gate Threshold Voltage (Vgs(th)): Must fall within compatible drive voltage ranges
• Package Type: Surface mount DPAK (TO-252-3) configuration required
• Operating Temperature Range: Must support -55°C to 175°C minimum

Identified Substitutes:

The IRFR3704 has two manufacturer-recommended substitutes from STMicroelectronics:

1. STD100N3LF3 – STripFET™ II series, rated 30V/80A
2. STD150N3LLH6 – DeepGATE™/STripFET™ VI series, rated 30V/80A

Both substitutes exceed the original part's voltage and current ratings while maintaining DPAK packaging and compatible operating temperature ranges. The higher voltage rating (30V vs. 20V) provides design margin. Both parts are RoHS3 compliant, addressing the non-compliant status of the original IRFR3704.

Parameter Comparison

Engineering Selection Recommendations

STD100N3LF3 Selection Criteria:

The STD100N3LF3 provides direct functional substitution with improved electrical performance. The 30V Vdss rating exceeds the original 20V specification, offering increased design margin for transient voltage spikes. The 80A continuous drain current matches application requirements. The 5.5mOhm on-state resistance at 40A represents improved efficiency compared to the IRFR3704's 9.5mOhm specification. ROHS3 compliance addresses regulatory requirements absent in the original part. This substitute is suitable for applications where lower on-state resistance and higher voltage margin are beneficial.

STD150N3LLH6 Selection Criteria:

The STD150N3LLH6 offers superior on-state resistance performance at 2.8mOhm, delivering the lowest conduction losses among available substitutes. The DeepGATE™ and STripFET™ VI technology series provides enhanced switching characteristics. The 30V Vdss and 80A Id ratings maintain compatibility with the original application envelope. ROHS3 compliance and identical operating temperature range ensure regulatory and thermal compatibility. This substitute is preferred for applications prioritizing thermal efficiency and power dissipation minimization.

Compliance Considerations:

Both substitutes are ROHS3 compliant, addressing the non-compliant status of the IRFR3704. Both maintain REACH unaffected status and EAR99 export classification. All three parts share identical HTSUS commodity codes (8541.29.0095) and MSL rating (1 – Unlimited).

Frequently Asked Questions (FAQ)

Q: Can STD100N3LF3 or STD150N3LLH6 be used as direct pin-for-pin replacements for IRFR3704?

A: Yes. Both substitutes use identical TO-252-3 DPAK packaging with the same pin configuration (Gate, Drain, Source + Tab). No PCB layout modifications are required for mechanical compatibility.

Q: What is the primary difference between the two substitute parts?

A: The STD150N3LLH6 features significantly lower on-state resistance (2.8mOhm vs. 5.5mOhm), resulting in reduced power dissipation and improved thermal performance. The STD100N3LF3 provides a more conservative upgrade with adequate performance margin. Selection depends on thermal budget and efficiency requirements of the specific application.

Q: Are there any gate drive voltage differences that affect circuit operation?

A: Both substitutes have lower gate threshold voltages (2.5V vs. 3V) and slightly higher gate charge values. Standard 10V gate drive circuits used with the IRFR3704 will operate both substitutes within specification. No gate driver modifications are necessary.

Q: How do the voltage ratings affect circuit design?

A: The 30V Vdss rating of both substitutes exceeds the original 20V specification. This provides additional margin for transient overvoltage conditions but does not require circuit redesign. Applications operating at or below 20V will function identically with either substitute.

Q: What is the impact of higher continuous drain current ratings (80A vs. 75A)?

A: The 80A rating provides 6.7% additional current capacity, offering design margin without requiring modifications. Thermal management and PCB current distribution remain compatible with original IRFR3704 designs.

Q: Do the substitutes maintain the same thermal characteristics?

A: Both substitutes have higher power dissipation ratings (110W vs. 90W) and lower on-state resistance values, resulting in improved thermal efficiency. Thermal management approaches used for the IRFR3704 will provide equal or superior performance with either substitute.

Q: Are there any supply chain or inventory considerations?

A: STD100N3LF3 has 15,465 units in stock, and STD150N3LLH6 has 10,300 units in stock, compared to 2,886 units of the obsolete IRFR3704. Both substitutes offer superior availability for production continuity.

Q: What compliance advantages do the substitutes offer?

A: Both STD100N3LF3 and STD150N3LLH6 are ROHS3 compliant, addressing the non-compliant status of the IRFR3704. This ensures compatibility with current environmental and regulatory requirements for new designs and production.