STP5NK40Z Equivalent & Substitute Parts

Part Overview

The STP5NK40Z is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 400V drain-to-source voltage with 3A continuous drain current at 25°C. This device is packaged in TO-220AB through-hole configuration and is part of the SuperMESH™ series. The STP5NK40Z is classified as obsolete, making identification of equivalent and substitute parts necessary for ongoing design support and component procurement. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and thermal characteristics while accommodating packaging variations.

Substiute Parts

STP5NK40Z

STMicroelectronicsIn Stock: 1233STP5NK40Z Datasheet

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IRF720LPBF

Vishay SiliconixIn Stock: 976IRF720LPBF Datasheet

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IRF720PBF

Vishay SiliconixIn Stock: 7601IRF720PBF Datasheet

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IRF730APBF

Vishay SiliconixIn Stock: 3458IRF730APBF Datasheet

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IRF730PBF

Vishay SiliconixIn Stock: 55199IRF730PBF Datasheet

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IXTP3N50D2

IXYSIn Stock: 1376IXTP3N50D2 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the STP5NK40Z are selected based on the following electrical and mechanical criteria:

Primary Substitution Criteria:

• Drain-to-Source Voltage (Vdss): 400V minimum (equal or higher rating acceptable)
• Continuous Drain Current (Id): 3A minimum at 25°C
• On-State Resistance (Rds On): Comparable performance at specified gate voltage
• Operating Temperature Range: -55°C to 150°C (TJ)
• Mounting Type: Through-hole configuration
• FET Type: N-Channel MOSFET technology

Grouping Logic:

Group 1 – Direct Package Equivalents (TO-220AB): Parts maintaining identical TO-220AB packaging with 400V rating and 3A+ current capacity. These provide pin-compatible substitution with minimal circuit board redesign.

Group 2 – Alternative Package Equivalents (TO-262-3): Parts with 400V rating and 3A+ current capacity in TO-262-3 packaging. These require PCB layout modification but maintain electrical compatibility.

Group 3 – Enhanced Current Rating (TO-220AB): Parts with 400V rating and current capacity exceeding 3A, providing design margin and thermal headroom while maintaining TO-220AB compatibility.

Group 4 – Higher Voltage Rating (TO-220-3): Parts with voltage rating exceeding 400V and matching current capacity, suitable for applications requiring additional voltage margin.

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Replacement (Preferred):

The IRF720PBF is the primary substitute for the STP5NK40Z. Both devices are packaged in TO-220AB with identical pinout, enabling direct board-level substitution without layout modification. The IRF720PBF maintains 400V Vdss rating with 3.3A continuous drain current, exceeding the original 3A specification. On-state resistance is equivalent at 1.8 Ohm, and operating temperature range matches the original specification. The IRF720PBF is in active production status with ROHS3 compliance and unlimited moisture sensitivity rating, ensuring long-term availability and regulatory compliance.

For Enhanced Thermal Performance:

The IRF730APBF and IRF730PBF provide increased current capacity (5.5A) and power dissipation (74W) while maintaining TO-220AB packaging and 400V voltage rating. These devices are suitable for applications requiring additional thermal margin or higher current handling. Both are in active production with ROHS3 compliance. The IRF730PBF offers the highest inventory availability (55,100 units) among all substitutes.

For Alternative Packaging (TO-262-3):

The IRF720LPBF provides 400V rating with 3.3A current capacity in TO-262-3 packaging. This option requires PCB redesign but offers equivalent electrical performance to the IRF720PBF. The TO-262-3 package provides improved thermal characteristics through enhanced lead configuration.

For Higher Voltage Applications:

The IXTP3N50D2 is rated for 500V Vdss with 3A continuous drain current, suitable for applications requiring voltage margin above 400V. This device is packaged in TO-220-3 (pin-compatible with TO-220AB) and is in active production status. Note: The IXTP3N50D2 is classified as depletion-mode technology, requiring circuit design verification for gate drive compatibility.

Compliance and Availability:

All substitute parts are ROHS3 compliant and carry MSL rating of 1 (unlimited moisture sensitivity). All devices maintain the -55°C to 150°C operating temperature range of the original part. Inventory availability ranges from 878 to 55,100 units across substitute options, ensuring procurement feasibility.

Frequently Asked Questions (FAQ)

Q: Can the IRF720PBF be used as a direct replacement for the STP5NK40Z without circuit modification?

A: Yes. The IRF720PBF is packaged in TO-220AB with identical pinout to the STP5NK40Z. Both devices feature N-Channel MOSFET technology with 400V Vdss rating. The IRF720PBF's 3.3A continuous drain current exceeds the original 3A specification, and on-state resistance is equivalent at 1.8 Ohm. No circuit modification is required for pin-compatible substitution.

Q: What is the difference between the IRF730APBF and IRF730PBF?

A: Both devices share identical electrical ratings: 400V Vdss, 5.5A continuous drain current, 74W power dissipation, and TO-220AB packaging. The primary differences are in gate charge specification (IRF730APBF: 22 nC; IRF730PBF: 38 nC) and input capacitance (IRF730APBF: 600 pF; IRF730PBF: 700 pF). The IRF730PBF offers significantly higher inventory availability (55,100 units versus 3,400 units).

Q: Why is the IXTP3N50D2 listed as a substitute if it has 500V rating instead of 400V?

A: The IXTP3N50D2 meets the primary substitution criteria of 400V minimum Vdss (500V exceeds this requirement), 3A continuous drain current, and TO-220-3 through-hole packaging. Higher voltage rating provides design margin for applications subject to voltage transients. However, the IXTP3N50D2 is depletion-mode technology, requiring verification of gate drive circuit compatibility with the original enhancement-mode design.

Q: What packaging considerations apply when selecting between TO-220AB and TO-262-3 options?

A: TO-220AB and TO-220-3 packages are mechanically and electrically compatible for direct board-level substitution. The TO-262-3 package (IRF720LPBF) requires PCB layout modification due to different lead spacing and mounting hole configuration. TO-262-3 packaging provides improved thermal performance through enhanced lead geometry, suitable for high-power applications. Selection depends on PCB design constraints and thermal requirements.

Q: Are all substitute parts RoHS compliant?

A: Yes. All substitute parts listed (IRF720LPBF, IRF720PBF, IRF730APBF, IRF730PBF, and IXTP3N50D2) are ROHS3 compliant. All devices carry MSL rating of 1 (unlimited moisture sensitivity), matching the original STP5NK40Z specification.

Q: What is the significance of the obsolete status of the STP5NK40Z?

A: Obsolete status indicates the STP5NK40Z is no longer in production by STMicroelectronics. All substitute parts listed are in active production status, ensuring long-term availability for new designs and ongoing support. Substitute selection prioritizes active-status devices to avoid future obsolescence issues.

Q: How do gate charge specifications affect device selection?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. The STP5NK40Z specifies 17 nC at 10V. Substitute parts range from 20 nC (IRF720 series) to 40 nC (IXTP3N50D2). Higher gate charge increases switching losses and requires higher gate drive current. For applications with fixed gate drive circuits, gate charge variation may affect switching frequency and efficiency. Verification of gate drive capability is recommended when gate charge exceeds original specification by more than 50%.

Q: What thermal considerations apply when selecting between 45W and 74W power dissipation ratings?

A: The STP5NK40Z is rated for 45W power dissipation at case temperature (Tc). Substitute parts with higher power dissipation ratings (IRF730 series at 74W, IXTP3N50D2 at 125W) provide thermal margin for applications approaching the original device's power limit. Higher power dissipation rating does not increase actual power consumption; it indicates the device can safely dissipate more heat. Selection depends on application power requirements and thermal management design.