MARR-5-37-43 Equivalent & Substitute Parts

Part Overview

The MARR-5-37-43 is a glass body reed switch manufactured by Littelfuse Inc., configured as a SPST-NO (Single Pole Single Throw - Normally Open) device. This component is rated for 350mA AC / 500mA DC switching at 265V AC and 1000V DC, with a 10W power rating and an operate range of 37–43AT. The part is currently obsolete, making identification of functionally equivalent alternatives essential for ongoing system maintenance and new design implementations.

Substiute Parts

MARR-5-37-43

Littelfuse Inc.In Stock: 984MARR-5-37-43 Datasheet

Current PartRFQ

MVSR-20-37-43

Littelfuse Inc.In Stock: 946MVSR-20-37-43 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the obsolete MARR-5-37-43 is determined by strict equivalence across the following critical electrical and mechanical parameters:

• Circuit Configuration: SPST-NO topology must be maintained
• Operate Range: 37–43AT activation threshold
• Current Ratings: 350mA AC / 500mA DC switching capacity
• Voltage Ratings: 265V AC / 1000V DC switching capability
• Power Rating: 10W maximum dissipation
• Timing Characteristics: 0.75ms operate time / 0.3ms release time
• Physical Form Factor: Through-hole axial termination, glass body reed switch construction
• Dimensional Compatibility: 2.235" overall length, 0.105" diameter body
• Environmental Compliance: ROHS3 compliance and MSL 1 rating

The MVSR-20-37-43 meets all these criteria and is classified as a direct functional equivalent.

Parameter Comparison

Engineering Selection Recommendations

The MVSR-20-37-43 is the direct equivalent substitute for the obsolete MARR-5-37-43. Both components are manufactured by Littelfuse Inc. and share identical electrical specifications, mechanical dimensions, and environmental compliance certifications. The MVSR-20-37-43 maintains active product status, ensuring availability for procurement and ongoing supply chain support. Both parts carry ROHS3 compliance and EAR99 export classification, with equivalent regulatory standing. Selection of the MVSR-20-37-43 provides functional continuity without design modification or circuit re-qualification.

Frequently Asked Questions (FAQ)

Q: Can the MVSR-20-37-43 be used as a direct replacement for the MARR-5-37-43 without circuit modification?

A: Yes. The MVSR-20-37-43 is electrically and mechanically equivalent. All switching parameters, voltage ratings, current ratings, timing characteristics, and physical dimensions are identical. Through-hole axial termination is compatible with existing PCB layouts designed for the MARR-5-37-43.

Q: What is the primary difference between these two parts?

A: The MARR-5-37-43 is obsolete, while the MVSR-20-37-43 is active. Both belong to different Littelfuse series (MARR-5 versus MVSR-20) but maintain complete functional equivalence.

Q: Are there any compliance or certification differences?

A: No. Both parts carry identical ROHS3 compliance, MSL 1 rating, EAR99 export classification, and HTSUS coding. Regulatory standing is equivalent.

Q: What packaging is available for the MVSR-20-37-43?

A: The MVSR-20-37-43 is supplied in box packaging. Verify packaging requirements against your procurement specifications.

Q: Are the operate and release times identical?

A: Yes. Both parts specify 0.75ms operate time and 0.3ms release time, ensuring equivalent switching performance in time-sensitive applications.

Q: Can these parts be used interchangeably in new designs?

A: Yes. The MVSR-20-37-43 is the recommended choice for new designs due to its active product status and assured long-term availability.