STP8NS25 Equivalent & Substitute Parts

Part Overview

The STP8NS25 is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 250V drain-to-source voltage and 8A continuous drain current in a TO-220 through-hole package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity. Active alternatives with comparable electrical characteristics and identical packaging are available from alternative manufacturers.

Substiute Parts

STP8NS25

STMicroelectronicsIn Stock: 2858STP8NS25 Datasheet

Current PartRFQ

RCX080N25

Rohm SemiconductorIn Stock: 7926RCX080N25 Datasheet

DirectRFQ

IRF634PBF

Vishay SiliconixIn Stock: 38338IRF634PBF Datasheet

SimilarRFQ

IRF644PBF

Vishay SiliconixIn Stock: 3380IRF644PBF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the STP8NS25 is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

• FET Type: N-Channel
• Drain to Source Voltage (Vdss): 250V
• Mounting Type: Through Hole
• Package / Case: TO-220-3 or compatible TO-220 variant
• Technology: MOSFET (Metal Oxide)

Functional Compatibility Parameters:

• Current - Continuous Drain (Id) @ 25°C: minimum 8A
• Drive Voltage (Max Rds On): 10V
• Operating Temperature (TJ): 150°C or higher
• RoHS Status: ROHS3 Compliant

Substitute parts must satisfy all critical matching parameters and maintain functional compatibility within the specified electrical operating range. Parts are classified as direct equivalents when all parameters align within tolerance, or as similar alternatives when current rating or power dissipation exceeds the original specification while maintaining voltage and package compatibility.

Parameter Comparison

Engineering Selection Recommendations

RCX080N25 (Rohm Semiconductor) — Direct Equivalent

The RCX080N25 is classified as a direct equivalent substitute for the STP8NS25. Both devices share identical voltage rating (250V Vdss), current rating (8A continuous drain current), drive voltage (10V), and TO-220-3 package configuration. The RCX080N25 maintains ROHS3 compliance and REACH unaffected status. This part is currently in active production status with 7890 units in stock inventory. The RCX080N25 exhibits lower gate charge (15nC versus 51.8nC) and reduced power dissipation rating (35W Tc versus 80W Tc), which may provide improved switching performance in applications with moderate thermal requirements. The higher Vgs(th) threshold (5V @ 1mA versus 4V @ 250µA) and increased Rds On (600mOhm versus 450mOhm) require verification against specific circuit bias conditions.

IRF634PBF (Vishay Siliconix) — Similar Alternative

The IRF634PBF is classified as a similar alternative with enhanced specifications. This device maintains the 250V voltage rating and TO-220-3 package, with marginally higher continuous drain current (8.1A versus 8A). The IRF634PBF provides identical Rds On performance (450mOhm @ 10V) and matching gate threshold voltage (4V @ 250µA). Extended operating temperature range (-55°C to 150°C versus 150°C maximum) provides additional thermal margin. Gate charge is reduced (41nC versus 51.8nC), and input capacitance remains equivalent (770pF). The IRF634PBF is in active production with 38261 units in stock inventory and maintains ROHS3 compliance with REACH unaffected status.

IRF644PBF (Vishay Siliconix) — Higher Current Alternative

The IRF644PBF is classified as a similar alternative for applications requiring higher current capacity. This device maintains the 250V voltage rating and TO-220-3 package with significantly elevated continuous drain current (14A versus 8A). The IRF644PBF provides superior Rds On performance (280mOhm @ 8.4A versus 450mOhm @ 4A), enabling reduced conduction losses in high-current applications. Power dissipation rating is substantially higher (125W versus 80W), supporting increased thermal headroom. Extended operating temperature range (-55°C to 150°C) matches the IRF634PBF. The IRF644PBF is in active production with 3281 units in stock inventory and maintains ROHS3 compliance. REACH status is affected, requiring compliance verification for regulated applications.

Frequently Asked Questions (FAQ)

Q: Can the RCX080N25 be used as a direct replacement for the STP8NS25 in all applications?

A: The RCX080N25 satisfies all critical electrical and mechanical matching parameters for direct substitution. However, the reduced power dissipation rating (35W Tc versus 80W Tc) and increased Rds On (600mOhm versus 450mOhm) require thermal and circuit analysis to confirm suitability for specific applications. The higher gate threshold voltage (5V @ 1mA) may affect switching characteristics in low-voltage gate drive circuits.

Q: What is the difference between the IRF634PBF and IRF644PBF?

A: Both devices are Vishay Siliconix alternatives with identical voltage ratings and TO-220-3 packaging. The IRF644PBF provides higher continuous drain current (14A versus 8.1A) and superior Rds On performance (280mOhm versus 450mOhm), resulting in higher power dissipation capability (125W versus 74W). The IRF644PBF is suitable for applications requiring higher current handling or reduced conduction losses. The IRF634PBF is appropriate for applications matching the original 8A specification with extended temperature range.

Q: Are all substitute parts pin-compatible with the STP8NS25?

A: All substitute parts utilize the TO-220-3 package configuration with identical pin assignments (Gate, Drain, Source). Physical mounting and electrical connection are directly compatible without modification. The RCX080N25 uses a TO-220FM variant, which maintains identical pin configuration and footprint compatibility.

Q: What compliance certifications apply to each substitute part?

A: All substitute parts maintain ROHS3 compliance. The RCX080N25 and IRF634PBF are REACH unaffected. The IRF644PBF is REACH affected, requiring compliance verification for applications subject to REACH regulations.

Q: How does gate charge affect device selection?

A: Gate charge (Qg) determines the energy required to switch the device and influences switching speed and gate drive circuit design. The RCX080N25 exhibits significantly lower gate charge (15nC versus 51.8nC), potentially enabling faster switching with reduced gate drive power. The IRF634PBF provides moderate reduction (41nC), while the IRF644PBF exhibits higher gate charge (68nC) due to increased current capacity. Gate drive circuit capability must accommodate the selected device's gate charge specification.

Q: Which substitute part provides the best thermal performance?

A: The IRF644PBF provides the highest power dissipation rating (125W Tc), supporting the greatest thermal headroom in high-power applications. The IRF634PBF offers moderate thermal capability (74W Tc). The RCX080N25 provides the lowest power dissipation rating (35W Tc), suitable for applications with moderate thermal requirements. Thermal performance selection depends on circuit power dissipation requirements and heat sink availability.

Q: Can the IRF644PBF be used in applications designed for 8A operation?

A: The IRF644PBF is electrically compatible with 8A applications due to its 250V voltage rating and TO-220-3 package. The higher current rating (14A) and superior Rds On performance (280mOhm) provide additional design margin and reduced conduction losses. No circuit modification is required for direct substitution in 8A applications.