IRLR8729TRLPBF N-Channel MOSFET 30V 58A Equivalent & Substitute Parts

Part Overview

The IRLR8729TRLPBF is an N-Channel MOSFET manufactured by Infineon Technologies, classified within the HEXFET® series. This device is rated for 30V drain-to-source voltage with 58A continuous drain current at 25°C and 55W maximum power dissipation in a Surface Mount TO-252AA (DPAK) package. The product status is listed as Obsolete, making identification of functionally equivalent substitute components necessary for ongoing design support and procurement.

Substiute Parts

IRLR8729TRLPBF

Infineon TechnologiesIn Stock: 104539IRLR8729TRLPBF Datasheet

Current PartRFQ

BUK7Y13-40B,115

Nexperia USA Inc.In Stock: 4803BUK7Y13-40B,115 Datasheet

MFR RecommendedRFQ

STD40NF03LT4

STMicroelectronicsIn Stock: 15229STD40NF03LT4 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRLR8729TRLPBF is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• FET Type: N-Channel topology
• Drain-to-Source Voltage (Vdss): Minimum 30V rating required
• Continuous Drain Current (Id): Minimum 58A at 25°C
• On-State Resistance (Rds On): Comparable performance at specified gate voltage
• Power Dissipation: Sufficient thermal capability for application requirements
• Operating Temperature Range: -55°C to 175°C compatibility
• Mounting Type: Surface Mount configuration
• RoHS Compliance: ROHS3 Compliant status

Secondary Considerations:

• Gate Charge (Qg) and Input Capacitance (Ciss) affect switching characteristics
• Package footprint compatibility (DPAK or equivalent)
• Product Status: Active status preferred for long-term availability

The substitute parts listed below meet or exceed the electrical specifications of the IRLR8729TRLPBF while maintaining compatibility with the defined application envelope.

Parameter Comparison

Engineering Selection Recommendations

BUK7Y13-40B,115 (Nexperia USA Inc.)

This substitute provides the closest electrical match to the IRLR8729TRLPBF with identical 58A continuous drain current rating. The device features a higher Vdss rating of 40V, providing additional voltage margin. Power dissipation capability is increased to 85W. The part is classified as Active with AEC-Q101 Automotive qualification, ensuring long-term availability and supply chain stability. Package transition from DPAK to LFPAK56 (Power-SO8) requires PCB layout modification but offers improved thermal performance. RoHS3 compliance and unlimited moisture sensitivity level (MSL 1) are maintained.

STD40NF03LT4 (STMicroelectronics)

This substitute maintains the same 30V Vdss rating and DPAK package as the main part, minimizing layout changes. Continuous drain current is rated at 40A, which is lower than the IRLR8729TRLPBF specification. This device is suitable for applications where the 58A rating is not fully utilized. The part is Active status with 80W power dissipation capability. Gate charge is higher at 30nC, which may affect switching frequency performance. RoHS3 compliance and MSL 1 rating are provided. Direct package compatibility simplifies design migration.

Selection Basis:

• Both substitute parts are Active status, providing superior long-term procurement availability compared to the Obsolete main part
• Electrical parameters meet or exceed the IRLR8729TRLPBF specifications within the defined application envelope
• All parts maintain RoHS3 compliance and unlimited moisture sensitivity rating
• Operating temperature range (-55°C to 175°C) is consistent across all devices
• Selection between substitutes depends on current requirement (58A vs. 40A) and package footprint constraints

Frequently Asked Questions (FAQ)

Q1: Can the BUK7Y13-40B,115 directly replace the IRLR8729TRLPBF without circuit modification?

The BUK7Y13-40B,115 provides electrical compatibility in terms of FET type, voltage rating, and current capability. However, the package transition from DPAK to LFPAK56 requires PCB layout redesign. Gate charge and input capacitance values differ slightly, which may affect switching characteristics in high-frequency applications. Thermal performance improves due to increased power dissipation rating (85W vs. 55W).

Q2: Why is the STD40NF03LT4 rated for only 40A when the main part is 58A?

The STD40NF03LT4 is a different device within the STripFET™ II series with lower continuous drain current specification. This part is suitable for applications where peak current requirements do not exceed 40A. The lower current rating does not indicate inferior quality but rather a different product positioned for lower-power applications. Verify application current requirements before selection.

Q3: What are the package compatibility implications?

The IRLR8729TRLPBF uses TO-252-3 (DPAK) package. The STD40NF03LT4 maintains this package, allowing direct PCB footprint compatibility. The BUK7Y13-40B,115 uses LFPAK56 (Power-SO8) package, requiring new PCB layout design. LFPAK56 offers superior thermal characteristics due to larger copper area and multiple thermal vias.

Q4: Are all substitute parts RoHS3 compliant?

Yes. Both the BUK7Y13-40B,115 and STD40NF03LT4 are ROHS3 Compliant, matching the compliance status of the main part. All parts are REACH Unaffected and classified under ECCN EAR99.

Q5: How do gate charge differences affect circuit performance?

Gate charge (Qg) determines the energy required to switch the FET on and off. The main part specifies 16nC at 4.5V, while substitutes range from 19nC to 30nC. Higher gate charge increases switching losses and may require higher gate drive current. In low-frequency applications, this difference is negligible. In high-frequency switching circuits, gate charge should be evaluated against driver capability.

Q6: What is the significance of the Automotive qualification on the BUK7Y13-40B,115?

AEC-Q101 qualification indicates the device meets automotive industry reliability and quality standards. This qualification is not required for all applications but provides assurance of manufacturing consistency and long-term reliability for mission-critical systems.

Q7: Can I use the STD40NF03LT4 in applications requiring 58A continuous current?

No. The STD40NF03LT4 is rated for 40A continuous drain current at 25°C. Using this device in applications requiring 58A would exceed the device specification and result in thermal stress, reduced reliability, and potential failure. The BUK7Y13-40B,115 is the appropriate substitute for 58A applications.