IRF734 Equivalent & Substitute Parts

Part Overview

The IRF734 is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 450V drain-to-source voltage with 4.9A continuous drain current at 25°C. This device is packaged in a Through Hole TO-220AB configuration and is designed for high-voltage switching applications. The IRF734 maintains Active product status with 2136 units currently in stock.

Substitute parts are identified when equivalent electrical performance can be achieved within the specified parameter tolerances while maintaining compatible mechanical packaging. Substitution becomes necessary when the primary part reaches end-of-life status, experiences supply constraints, or when design requirements permit operation within the electrical specifications of alternative devices.

Substiute Parts

IRF734

Vishay SiliconixIn Stock: 2234IRF734 Datasheet

Current PartRFQ

FQP6N40CF

onsemiIn Stock: 1938FQP6N40CF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRF734 is determined by the following critical parameters:

Electrical Compatibility Criteria:

• FET Type must be N-Channel
• Drain to Source Voltage (Vdss) must be equal to or greater than 450V
• Continuous Drain Current (Id) must be equal to or greater than 4.9A at 25°C
• Rds On (Max) must not exceed the specified value at rated conditions
• Power Dissipation (Max) must support the thermal requirements
• Operating Temperature Range must encompass -55°C to 150°C (TJ)

Mechanical Compatibility Criteria:

• Mounting Type must be Through Hole
• Package / Case must be TO-220-3 or equivalent TO-220AB configuration

The FQP6N40CF from onsemi is identified as a substitute part. While this device operates at a lower Vdss rating of 400V, it meets or exceeds all other critical electrical parameters and maintains identical mechanical packaging. This substitution is valid only in applications where the maximum operating voltage does not exceed 400V.

Parameter Comparison

Engineering Selection Recommendations

IRF734 (Vishay Siliconix) - Primary Selection

The IRF734 maintains Active product status with established supply availability (2136 units in stock). This device is RoHS non-compliant. Selection of the IRF734 is appropriate for applications requiring the full 450V Vdss rating and where RoHS compliance is not a design requirement.

FQP6N40CF (onsemi) - Substitute Selection

The FQP6N40CF is classified as Obsolete but remains available (1829 units in stock). This device is ROHS3 Compliant and REACH Unaffected, making it suitable for applications with environmental compliance requirements. The FQP6N40CF operates at 400V Vdss, which represents a 50V reduction from the IRF734 specification. This substitution is valid only in circuit designs where the maximum operating voltage does not exceed 400V. The FQP6N40CF provides superior electrical performance in gate charge (20 nC versus 45 nC) and input capacitance (625 pF versus 680 pF), resulting in faster switching characteristics.

Selection between these devices depends on three factors: (1) maximum operating voltage requirement, (2) RoHS compliance mandate, and (3) supply chain availability.

Frequently Asked Questions (FAQ)

Q: Can the FQP6N40CF replace the IRF734 in all applications?

A: No. The FQP6N40CF operates at a maximum Vdss of 400V, compared to the IRF734's 450V rating. Substitution is valid only in applications where the circuit voltage does not exceed 400V. Applications requiring the full 450V rating must use the IRF734 or an equivalent 450V-rated device.

Q: What are the key electrical advantages of the FQP6N40CF?

A: The FQP6N40CF provides higher continuous drain current (6A versus 4.9A), lower on-resistance (1.1 Ohm versus 1.2 Ohm), lower gate charge (20 nC versus 45 nC), and lower input capacitance (625 pF versus 680 pF). These characteristics result in improved switching speed and reduced gate drive requirements.

Q: Are the packages mechanically identical?

A: Yes. Both devices use the TO-220-3 package with Through Hole mounting. Pin configuration and mechanical dimensions are compatible, allowing direct physical substitution in PCB layouts designed for either device.

Q: What is the significance of the FQP6N40CF's Obsolete status?

A: Obsolete status indicates that onsemi has discontinued active production and support for this device. While 1829 units are currently in stock, long-term availability cannot be guaranteed. The IRF734, with Active status, provides greater supply security for new designs.

Q: Does RoHS compliance affect electrical performance?

A: No. RoHS compliance is a manufacturing and material specification that does not alter the electrical characteristics of the device. The FQP6N40CF's ROHS3 Compliant status makes it suitable for applications with environmental regulations, while the IRF734's RoHS non-compliant status may restrict its use in regulated markets.

Q: How do gate charge differences impact circuit design?

A: Gate charge (Qg) determines the energy required to switch the device. The FQP6N40CF's lower gate charge (20 nC) requires less gate drive energy compared to the IRF734 (45 nC), resulting in reduced power consumption in the gate drive circuit and potentially faster switching transitions.

Q: Can these devices be used interchangeably in existing designs?

A: Interchangeability depends on the circuit's maximum operating voltage. If the design operates below 400V, the FQP6N40CF can be substituted with potential performance improvements. If the design requires 400V to 450V operation, only the IRF734 is suitable.