IRLR3705ZPBF N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The IRLR3705ZPBF is an N-Channel MOSFET manufactured by Infineon Technologies, rated for 55V drain-to-source voltage with 42A continuous drain current at 25°C. This device is housed in a TO-252-3 DPAK surface mount package and is part of the HEXFET® series. The part is currently discontinued at DiGi Electronics, making equivalent substitute components necessary for ongoing design support and procurement.

The IRLR3705ZPBF serves in switching applications requiring moderate voltage and current ratings with low on-resistance characteristics. Substitute parts must maintain compatibility with the DPAK package footprint and preserve the electrical performance envelope defined by the original specification.

Substiute Parts

IRLR3705ZPBF

Infineon TechnologiesIn Stock: 1839IRLR3705ZPBF Datasheet

Current PartRFQ

BUK7212-55B,118

Nexperia USA Inc.In Stock: 7283BUK7212-55B,118 Datasheet

MFR RecommendedRFQ

BUK9217-75B,118

Nexperia USA Inc.In Stock: 13491BUK9217-75B,118 Datasheet

MFR RecommendedRFQ

DMTH6010LK3-13

Diodes IncorporatedIn Stock: 3990DMTH6010LK3-13 Datasheet

MFR RecommendedRFQ

STD60NF55LT4

STMicroelectronicsIn Stock: 17844STD60NF55LT4 Datasheet

MFR RecommendedRFQ

STD65N55F3

STMicroelectronicsIn Stock: 15179STD65N55F3 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRLR3705ZPBF is determined by the following critical parameters:

Voltage Rating Compatibility: All substitute parts must maintain a Vdss rating of 55V or higher to ensure safe operation within the original design envelope.

Current Rating Compatibility: Substitute parts must support a continuous drain current (Id) of at least 42A at 25°C to meet or exceed the original performance specification.

On-Resistance (Rds On): The maximum on-resistance specification of 8mOhm at 42A, 10V defines the switching efficiency requirement. Substitute parts with equal or lower Rds On values maintain thermal and efficiency characteristics.

Package Compatibility: All substitutes must use the TO-252-3 DPAK surface mount package to ensure mechanical and electrical compatibility with existing PCB layouts.

Gate Charge (Qg): Gate charge specifications affect switching speed and driver circuit requirements. Substitute parts with comparable Qg values (typically 35-66 nC) maintain gate drive compatibility.

Temperature Range: Operating temperature range of -55°C to 175°C or higher ensures functional equivalence across the design temperature envelope.

Compliance Status: RoHS3 compliance and REACH unaffected status are mandatory for regulatory equivalence.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: STD65N55F3

The STD65N55F3 from STMicroelectronics is the preferred substitute for the IRLR3705ZPBF. This device maintains the 55V Vdss rating and exceeds the 42A continuous drain current requirement with an 80A rating. The on-resistance of 8.5mOhm at 32A, 10V is comparable to the original specification. The STD65N55F3 is currently active in production, ensuring long-term availability. It is housed in the identical TO-252-3 DPAK package and carries ROHS3 compliance. The operating temperature range of -55°C to 175°C matches the original specification.

Secondary Substitute: STD60NF55LT4

The STD60NF55LT4 from STMicroelectronics provides an alternative with 55V Vdss and 60A continuous drain current, exceeding the 42A requirement. This device is part of the STripFET™ II series and is currently active. The on-resistance specification of 15mOhm at 30A, 10V is higher than the original, resulting in increased power dissipation in high-current applications. The TO-252-3 DPAK package and ROHS3 compliance ensure compatibility. This substitute is suitable for applications where the higher on-resistance is acceptable.

Tertiary Substitute: BUK7212-55B,118

The BUK7212-55B,118 from Nexperia USA Inc. maintains 55V Vdss with 75A continuous drain current. This device is qualified to AEC-Q101 automotive standards and carries an extended operating temperature range to 185°C. The on-resistance of 12mOhm at 25A, 10V is higher than the original specification. Although the product status is listed as obsolete, current inventory of 7248 pieces is available. The DPAK package and ROHS3 compliance are maintained.

Alternative Substitute: DMTH6010LK3-13

The DMTH6010LK3-13 from Diodes Incorporated offers a 60V Vdss rating with 70A continuous drain current at Tc. The on-resistance of 8mOhm at 20A, 10V matches the original specification. This device is currently active in production. The power dissipation specification of 3.1W (Ta) differs from the original measurement basis, requiring thermal analysis for high-power applications. The TO-252-3 DPAK package and ROHS3 compliance are maintained.

Frequently Asked Questions (FAQ)

Q: Can the STD65N55F3 be used as a direct replacement for the IRLR3705ZPBF?

A: Yes. Both devices share the same 55V Vdss rating, TO-252-3 DPAK package, and comparable on-resistance characteristics. The STD65N55F3 exceeds the 42A current requirement with an 80A rating, providing design margin. Gate charge and threshold voltage specifications are within acceptable ranges for standard gate driver circuits.

Q: What is the impact of higher on-resistance in the STD60NF55LT4 substitute?

A: The STD60NF55LT4 has an on-resistance of 15mOhm compared to 8mOhm in the original IRLR3705ZPBF. At 42A continuous current, this results in approximately 26.5W additional power dissipation (I²R loss). Thermal management and heatsinking requirements must be re-evaluated for applications operating at maximum current.

Q: Are all substitute parts available in the same package?

A: Yes. All substitute parts listed are housed in the TO-252-3 DPAK surface mount package, ensuring mechanical compatibility with existing PCB layouts. No footprint modifications are required.

Q: What is the significance of the BUK7212-55B,118 being listed as obsolete?

A: Although the product status is obsolete, current inventory of 7248 pieces is available from stock. Obsolete status indicates that the manufacturer is not accepting new orders, but existing stock remains available for procurement. Long-term availability cannot be guaranteed.

Q: How do gate charge specifications affect circuit design?

A: Gate charge (Qg) determines the total charge required to switch the MOSFET from off to on state. The IRLR3705ZPBF specifies 66 nC at 5V, while substitutes range from 35 to 56 nC. Lower gate charge reduces switching losses and allows faster switching speeds. Gate driver circuits must be verified to supply adequate charge within the required switching time.

Q: Is the DMTH6010LK3-13 suitable for high-power continuous operation?

A: The DMTH6010LK3-13 specifies power dissipation of 3.1W (Ta), which is significantly lower than the original 130W (Tc) specification. This difference reflects different measurement conditions (ambient temperature Ta versus case temperature Tc). Thermal analysis is required to confirm suitability for applications requiring sustained high-power operation.

Q: What compliance certifications are maintained across all substitutes?

A: All substitute parts maintain ROHS3 compliance and REACH unaffected status, matching the original IRLR3705ZPBF. The BUK7212-55B,118 and BUK9217-75B,118 additionally carry AEC-Q101 automotive qualification, suitable for automotive applications.

Q: Can the BUK9217-75B,118 be used as a substitute despite its 75V Vdss rating?

A: The BUK9217-75B,118 has a 75V Vdss rating, which exceeds the 55V requirement of the original design. While this provides voltage margin, the higher voltage rating typically results in increased on-resistance and input capacitance. At 75V Vdss, this device is not an optimal substitute for a 55V application and should be considered only when higher voltage capability is required.