FQB55N06TM Equivalent & Substitute Parts

Part Overview

The FQB55N06TM is an N-Channel MOSFET manufactured by onsemi, rated for 60V drain-to-source voltage with 55A continuous drain current in a D2PAK surface mount package. This device is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and procurement continuity. The part belongs to the QFET® series and is suitable for applications requiring moderate-to-high current switching at 60V operating levels.

Substiute Parts

FQB55N06TM

onsemiIn Stock: 5189FQB55N06TM Datasheet

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PSMN015-60BS,118

Nexperia USA Inc.In Stock: 12771PSMN015-60BS,118 Datasheet

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STB55NF06LT4

STMicroelectronicsIn Stock: 1382STB55NF06LT4 Datasheet

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STB55NF06T4

STMicroelectronicsIn Stock: 18921STB55NF06T4 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FQB55N06TM is determined by the following critical parameters:

Voltage Rating: All substitute parts must maintain the 60V Vdss specification to ensure safe operation within the same voltage domain.

Current Rating: The FQB55N06TM is rated for 55A continuous drain current. Substitute parts with equal or higher current ratings (50A minimum) are acceptable for direct replacement without circuit redesign.

Package Type: All substitutes must use the D2PAK (TO-263-3) surface mount package to ensure mechanical and thermal compatibility with existing PCB layouts.

On-Resistance (Rds On): The 20mOhm specification at 27.5A and 10V drive voltage establishes the switching efficiency baseline. Substitute parts with lower or comparable Rds On values maintain or improve thermal performance.

Operating Temperature Range: All substitutes must support the -55°C to 175°C junction temperature range to ensure reliability across the full application temperature spectrum.

Gate Charge (Qg): The 46nC gate charge specification influences switching speed and driver circuit requirements. Substitute parts with lower gate charge reduce driver stress and improve switching performance.

The three substitute parts listed below meet these critical parameters within acceptable engineering tolerances for direct replacement applications.

Parameter Comparison

Engineering Selection Recommendations

STB55NF06LT4 (STMicroelectronics): This part provides the closest electrical match to the FQB55N06TM, maintaining 55A continuous drain current and 60V Vdss rating. The STB55NF06LT4 features improved on-resistance (18mOhm versus 20mOhm) and reduced gate charge (37nC versus 46nC), resulting in lower switching losses and improved thermal efficiency. The device is active in production with ROHS3 compliance and REACH unaffected status, ensuring long-term availability and regulatory compliance. This part is the primary recommendation for direct replacement in applications where the original 55A current rating is required.

STB55NF06T4 (STMicroelectronics): This alternative maintains the 60V Vdss specification with a reduced continuous drain current rating of 50A. The STB55NF06T4 offers comparable on-resistance (18mOhm) and improved power dissipation capability (110W versus 133W). This part is suitable for applications where the 55A current requirement can be reduced to 50A without circuit redesign. Active production status and ROHS3 compliance provide regulatory and supply chain continuity.

PSMN015-60BS,118 (Nexperia USA Inc.): This part maintains the 60V Vdss specification with a 50A continuous drain current rating. The PSMN015-60BS,118 features the lowest on-resistance (14.8mOhm) and lowest gate charge (20.9nC) among the substitute options, delivering superior switching efficiency and reduced driver circuit stress. The reduced power dissipation rating (86W) reflects the improved thermal characteristics. This part is suitable for applications where current requirements can be reduced to 50A and where enhanced switching performance is beneficial. Active production status ensures availability.

All three substitute parts share identical operating temperature ranges (-55°C to 175°C), D2PAK package configuration, and REACH unaffected regulatory status with the original FQB55N06TM.

Frequently Asked Questions (FAQ)

Q: Can the STB55NF06T4 or PSMN015-60BS,118 be used as direct replacements for the FQB55N06TM in all applications?

A: Direct replacement is possible only if the application circuit can operate at the reduced 50A continuous drain current rating. Both parts maintain the 60V Vdss specification and D2PAK package compatibility. Circuit analysis is required to confirm that peak and continuous current demands do not exceed 50A.

Q: What is the significance of the on-resistance (Rds On) differences between the FQB55N06TM and substitute parts?

A: Lower on-resistance reduces conduction losses and heat generation during switching. The STB55NF06LT4 (18mOhm) and STB55NF06T4 (18mOhm) reduce losses by approximately 10% compared to the FQB55N06TM (20mOhm). The PSMN015-60BS,118 (14.8mOhm) reduces losses by approximately 26%, improving thermal performance and efficiency.

Q: Are there thermal management differences between these parts?

A: The power dissipation ratings reflect thermal performance under specified conditions. The FQB55N06TM is rated for 133W (Tc), while the STB55NF06LT4 is rated for 95W (Tc), the STB55NF06T4 for 110W (Tc), and the PSMN015-60BS,118 for 86W (Tc). These differences are primarily due to current rating variations and on-resistance characteristics. Thermal design must account for the specific power dissipation rating of the selected substitute.

Q: Do all substitute parts use the same D2PAK package?

A: Yes. All substitute parts use the D2PAK (TO-263-3) surface mount package with identical pinout and thermal tab configuration. PCB layout modifications are not required for package compatibility.

Q: What is the gate charge (Qg) significance when selecting a substitute?

A: Gate charge determines the energy required to switch the MOSFET on and off. Lower gate charge reduces driver circuit stress and switching losses. The FQB55N06TM requires 46nC at 10V. The STB55NF06LT4 requires 37nC at 4.5V, the STB55NF06T4 requires 60nC at 10V, and the PSMN015-60BS,118 requires 20.9nC at 10V. Lower gate charge values improve switching speed and reduce driver power consumption.

Q: Are there compliance or regulatory differences between the FQB55N06TM and substitute parts?

A: All parts share REACH unaffected status. The STB55NF06LT4 and STB55NF06T4 are ROHS3 compliant, providing enhanced regulatory alignment for new designs. The FQB55N06TM is obsolete, making the active production status of all substitute parts advantageous for long-term supply chain security.

Q: What is the impact of the different gate threshold voltages (Vgs(th)) on circuit operation?

A: Gate threshold voltage determines the minimum gate-source voltage required to turn the MOSFET on. The FQB55N06TM specifies 4V at 250µA, the STB55NF06LT4 specifies 4.7V at 250µA, the STB55NF06T4 specifies 4V at 250µA, and the PSMN015-60BS,118 specifies 4V at 1mA. These variations are within typical driver circuit operating ranges and do not require circuit redesign for standard gate drive implementations.

Q: Can the FQB55N06TM be used in new designs, or should substitute parts be selected?

A: The FQB55N06TM is classified as obsolete. New designs should select from the active substitute parts listed to ensure long-term availability, supply chain continuity, and regulatory compliance. The STB55NF06LT4 is recommended for applications requiring the full 55A current rating, while the STB55NF06T4 or PSMN015-60BS,118 are suitable for 50A applications.