Equivalent & Substitute Parts for F55J7R5

Part Overview

The F55J7R5 is a 7.5 Ohms ±5% 55W wirewound chassis mount resistor manufactured by Ohmite, part of the Stackohm® 250 series. This component is designed for high-power applications requiring reliable thermal dissipation and mechanical stability through flange-braced mounting. The part is currently active in production with 640 units in stock. Alternative models may be required due to application-specific power requirements, compliance needs, or inventory constraints.

Substiute Parts

F55J7R5

OhmiteIn Stock: 674F55J7R5 Datasheet

Current PartRFQ

F40J7R5E

OhmiteIn Stock: 1176F40J7R5E Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The F40J7R5E qualifies as a parametric equivalent to the F55J7R5 based on the following criteria:

Matching Parameters:

• Resistance value: 7.5 Ohms
• Tolerance: ±5%
• Composition: Wirewound
• Temperature Coefficient: ±400ppm/°C
• Operating Temperature Range: -55°C to 350°C
• Coating: Vitreous Enamel Coated
• Mounting Feature: Flange Braces, Right Angle
• Lead Style: Solder Lugs
• Package Type: Radial, Flat Oval

Differing Parameter:

• Power Rating: 40W (versus 55W for F55J7R5)
• Physical Dimensions: 2.000" L x 1.000" W (versus 4.600" L x 1.000" W)

The F40J7R5E maintains electrical equivalence in resistance, tolerance, and thermal characteristics. The reduced power rating and smaller physical footprint make this substitute suitable for applications where the full 55W capacity is not required.

Parameter Comparison

Engineering Selection Recommendations

F55J7R5 Selection Criteria:

• Applications requiring full 55W power dissipation capacity
• Designs where maximum thermal headroom is specified
• RoHS compliance not required for the application

F40J7R5E Selection Criteria:

• Applications with power dissipation requirements at or below 40W
• Designs where ROHS3 compliance is mandatory
• Space-constrained layouts where the reduced 2.000" length provides advantage
• Higher inventory availability (1122 units versus 640 units)

Both parts maintain identical electrical characteristics in resistance, tolerance, and temperature coefficient. Selection between them depends on power budget requirements and regulatory compliance constraints.

Frequently Asked Questions (FAQ)

Q: Can F40J7R5E replace F55J7R5 in all applications?

A: No. The F40J7R5E is suitable only for applications where the actual power dissipation does not exceed 40W. If your circuit requires the full 55W capacity, the F55J7R5 must be used.

Q: Are the resistance values identical between these parts?

A: Yes. Both parts provide 7.5 Ohms ±5% resistance with identical temperature coefficients of ±400ppm/°C.

Q: What is the physical difference between these parts?

A: The F40J7R5E has a shorter length of 2.000" compared to the F55J7R5 at 4.600". Width and seated height remain identical. Both use the same flange-braced, right-angle mounting configuration.

Q: Does the F40J7R5E meet RoHS requirements?

A: Yes. The F40J7R5E is ROHS3 compliant, while the F55J7R5 is RoHS non-compliant. If RoHS compliance is required, the F40J7R5E must be selected provided power requirements do not exceed 40W.

Q: Are the lead styles and package types compatible?

A: Yes. Both parts use solder lugs as the lead style and radial flat oval package configuration, ensuring mechanical and electrical compatibility in mounting.

Q: What is the temperature operating range for both parts?

A: Both the F55J7R5 and F40J7R5E operate across -55°C to 350°C, providing identical thermal performance characteristics.