STP75NF68 Equivalent & Substitute Parts

Part Overview

The STP75NF68 is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 68V drain-to-source voltage and 80A continuous drain current in a Through Hole TO-220-3 package. This device is part of the STripFET™ II series and is classified as Obsolete. Due to its obsolete status, equivalent substitute parts are necessary for new designs and ongoing production requirements. The following substitute MOSFETs provide functional alternatives based on electrical and mechanical compatibility within the N-Channel MOSFET category.

Substiute Parts

STP75NF68

STMicroelectronicsIn Stock: 1670STP75NF68 Datasheet

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IRFZ44VZPBF

Infineon TechnologiesIn Stock: 2315IRFZ44VZPBF Datasheet

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IRFZ44ZPBF

Infineon TechnologiesIn Stock: 1486IRFZ44ZPBF Datasheet

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IXTP70N075T2

IXYSIn Stock: 1021IXTP70N075T2 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STP75NF68 is determined by electrical and mechanical compatibility within the N-Channel MOSFET category. The critical parameters for substitution are:

Electrical Compatibility Criteria:

• Drain to Source Voltage (Vdss) must be equal to or greater than 68V
• Continuous Drain Current (Id) must be equal to or greater than 80A
• Gate threshold voltage (Vgs(th)) must be compatible at 4V @ 250µA
• Maximum gate voltage (Vgs Max) must be ±20V or greater
• Operating temperature range must encompass -55°C ~ 175°C

Mechanical Compatibility Criteria:

• Mounting type: Through Hole
• Package: TO-220-3 or equivalent TO-220AB
• Moisture Sensitivity Level: 1 (Unlimited)

Regulatory Compliance:

• RoHS3 Compliant
• REACH Unaffected
• ECCN: EAR99

The substitute parts listed below meet these criteria and are suitable for direct replacement in applications requiring N-Channel MOSFET functionality with the specified electrical and thermal characteristics.

Parameter Comparison

Engineering Selection Recommendations

IXTP70N075T2 (Recommended Primary Substitute)

The IXTP70N075T2 manufactured by IXYS is the recommended primary substitute for the STP75NF68. This device maintains Active product status, ensuring ongoing availability and manufacturer support. The IXTP70N075T2 provides a Drain to Source Voltage of 75V, which exceeds the original 68V specification, and delivers 70A continuous drain current, which approaches the original 80A rating. The device is ROHS3 Compliant and REACH Unaffected, matching the regulatory compliance profile of the original part. The TO-220-3 package and Through Hole mounting type provide direct mechanical compatibility. Operating temperature range of -55°C ~ 175°C aligns with the original specification.

IRFZ44VZPBF (Secondary Substitute)

The IRFZ44VZPBF manufactured by Infineon Technologies is classified as Not For New Designs but remains available for legacy system support. This device provides 60V Drain to Source Voltage and 57A continuous drain current. While these ratings are lower than the original STP75NF68, the IRFZ44VZPBF is suitable for applications where the full electrical specifications of the original part are not required. ROHS3 Compliance and REACH Unaffected status are maintained. The TO-220-3 package ensures mechanical compatibility.

IRFZ44ZPBF (Secondary Substitute)

The IRFZ44ZPBF manufactured by Infineon Technologies is also classified as Not For New Designs. This device provides 55V Drain to Source Voltage and 51A continuous drain current, representing the lowest electrical ratings among the substitute options. The IRFZ44ZPBF is suitable only for applications with reduced voltage and current requirements compared to the original STP75NF68. ROHS3 Compliance and REACH Unaffected status are maintained. The TO-220-3 package provides mechanical compatibility.

For new designs, the IXTP70N075T2 is the preferred selection due to its Active product status and superior electrical specifications. For legacy system maintenance where the original STP75NF68 is no longer available, the IRFZ44VZPBF or IRFZ44ZPBF may be considered only if application requirements permit reduced voltage and current ratings.

Frequently Asked Questions (FAQ)

Q: Can the IXTP70N075T2 be used as a direct replacement for the STP75NF68?

A: The IXTP70N075T2 is mechanically compatible through the TO-220-3 package and electrically compatible within the N-Channel MOSFET category. The IXTP70N075T2 provides 75V Vdss and 70A Id, which meet or exceed the original 68V and 80A specifications. However, the 70A continuous drain current is slightly lower than the original 80A rating. Application-specific thermal and current requirements must be evaluated to confirm suitability.

Q: Why are IRFZ44VZPBF and IRFZ44ZPBF listed as substitutes if they have lower voltage and current ratings?

A: These devices are listed as substitutes because they meet the fundamental electrical and mechanical compatibility criteria for N-Channel MOSFETs in the TO-220-3 package. However, their lower Vdss (60V and 55V respectively) and lower Id ratings (57A and 51A respectively) restrict their use to applications where these reduced specifications are acceptable. They are suitable only for legacy system support where the original STP75NF68 is unavailable and application requirements permit operation at lower electrical ratings.

Q: What is the significance of the Product Status field in the parameter comparison?

A: Product Status indicates the manufacturer's support and availability commitment. The STP75NF68 is Obsolete, meaning the manufacturer no longer produces or supports this device. IRFZ44VZPBF and IRFZ44ZPBF are classified as Not For New Designs, indicating limited manufacturer support for new applications. The IXTP70N075T2 is Active, meaning the manufacturer continues production and provides full technical support. For new designs, Active status devices are preferred.

Q: Are all substitute parts RoHS3 Compliant and REACH Unaffected?

A: Yes. All substitute parts listed in this document are ROHS3 Compliant and REACH Unaffected, matching the regulatory compliance profile of the original STP75NF68. All devices maintain Moisture Sensitivity Level 1 (Unlimited), indicating no special moisture handling requirements during storage or assembly.

Q: What is the impact of different Gate Charge (Qg) values on substitution?

A: Gate Charge affects switching speed and gate drive circuit requirements. The STP75NF68 has a Qg of 75 nC @ 10V, while substitutes range from 43 nC to 65 nC. Lower gate charge values result in faster switching and reduced gate drive power requirements. The IRFZ44ZPBF has the lowest gate charge at 43 nC, while the IXTP70N075T2 has 46 nC. These differences may affect circuit performance in high-frequency switching applications but do not prevent functional substitution in standard applications.

Q: How do differences in Input Capacitance (Ciss) affect circuit performance?

A: Input Capacitance affects gate drive circuit impedance and switching transient behavior. The STP75NF68 has Ciss of 2550 pF @ 25V, while the IXTP70N075T2 has 2725 pF, which is comparable. The IRFZ44VZPBF and IRFZ44ZPBF have lower Ciss values of 1690 pF and 1420 pF respectively. Lower input capacitance generally results in faster switching transitions and reduced gate drive power. These differences are within acceptable ranges for most applications but should be evaluated in high-frequency or high-speed switching circuits.

Q: What is the significance of Rds On (On-State Drain-Source Resistance) in substitution?

A: Rds On directly affects power dissipation and thermal performance. The STP75NF68 has Rds On of 14mOhm @ 40A, 10V. The IXTP70N075T2 has 12mOhm @ 25A, 10V, which is lower and indicates better on-state efficiency. The IRFZ44VZPBF has 12mOhm @ 34A, 10V, and the IRFZ44ZPBF has 13.9mOhm @ 31A, 10V. Lower Rds On values reduce conduction losses and heat generation, improving overall circuit efficiency. However, Rds On is measured at different current levels for each device, so direct comparison requires normalization to the same operating point.

Q: Can the substitute parts handle the same power dissipation as the original STP75NF68?

A: The STP75NF68 has a maximum power dissipation of 190W (Tc). The IXTP70N075T2 has 150W (Tc), which is lower. The IRFZ44VZPBF has 92W (Tc), and the IRFZ44ZPBF has 80W (Tc), both significantly lower. These differences reflect the lower current and voltage ratings of the substitute devices. In applications requiring the full 190W dissipation capability of the original part, only the IXTP70N075T2 approaches this specification at 150W. Thermal management and heat sink design must be re-evaluated when substituting to lower power-rated devices.

Q: Are there any package differences between the substitute parts?

A: All substitute parts use the TO-220-3 package or TO-220AB variant, which are mechanically equivalent. The TO-220-3 and TO-220AB designations refer to the same physical package with three leads (Gate, Drain, Source) suitable for Through Hole mounting. No package adapter or modification is required for direct substitution on existing PCBs designed for the STP75NF68.