MRPR-3-37-43 Equivalent & Substitute Parts

Part Overview

The MRPR-3-37-43 is a glass body reed switch manufactured by Littelfuse Inc., configured as a single-pole single-throw normally open (SPST-NO) device. This component is rated for 1.1A AC / 1.5A DC switching at 140V AC / 200V DC with a 50W power rating and operates within the 37–43AT magnetic field range. The part is currently classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and component procurement.

Substiute Parts

MRPR-3-37-43

Littelfuse Inc.In Stock: 782MRPR-3-37-43 Datasheet

Current PartRFQ

MRPR-20-37-43

Littelfuse Inc.In Stock: 1217MRPR-20-37-43 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The MRPR-20-37-43 qualifies as a direct substitute for the MRPR-3-37-43 based on the following critical parameters:

• Circuit Configuration: Both parts are SPST-NO reed switches with identical switching behavior
• Operate Range: Both operate within the 37–43AT magnetic field range, ensuring identical actuation characteristics
• Current Rating: Both support 1.1A AC / 1.5A DC switching capacity
• Power Rating: Both are rated for 50W maximum power dissipation
• Switching Timing: Both exhibit 0.75 ms operate time and 0.3 ms release time
• Mounting and Termination: Both use through-hole mounting with axial termination, ensuring mechanical and electrical compatibility
• Operating Temperature: The MRPR-20-37-43 operates from -20°C to 125°C, which encompasses the primary operating range of the MRPR-3-37-43 (-40°C to 125°C) for most applications above -20°C
• Compliance: Both are ROHS3 compliant with MSL 1 rating

The primary difference is the voltage rating: the MRPR-20-37-43 provides higher voltage switching capability (265V AC / 250V DC) compared to the MRPR-3-37-43 (140V AC / 200V DC), making it suitable for applications requiring the original part's voltage specifications or lower.

Parameter Comparison

Engineering Selection Recommendations

The MRPR-20-37-43 is the designated substitute for the obsolete MRPR-3-37-43. Selection criteria are based on the following factors:

• Product Status: The MRPR-3-37-43 is obsolete, while the MRPR-20-37-43 is active and available in production quantities (1166 pcs in stock versus 691 pcs for the original part)
• Functional Equivalence: Both parts maintain identical switching characteristics, current ratings, power dissipation, and timing parameters
• Compliance Continuity: Both parts maintain ROHS3 compliance and MSL 1 rating, ensuring regulatory and environmental compatibility
• Voltage Margin: The MRPR-20-37-43 provides higher voltage switching capability, offering additional design margin for applications operating at or below the original part's voltage specifications
• Temperature Consideration: Applications requiring operation below -20°C should evaluate the reduced lower temperature limit of the MRPR-20-37-43 against system requirements

Frequently Asked Questions (FAQ)

Q: Can the MRPR-20-37-43 directly replace the MRPR-3-37-43 in existing designs?

A: Yes. Both parts share identical circuit configuration (SPST-NO), operate range (37–43AT), current ratings (1.1A AC / 1.5A DC), power rating (50W), and switching timing (0.75 ms operate / 0.3 ms release). Through-hole axial termination is identical, ensuring mechanical and electrical compatibility without PCB modification.

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

A: The MRPR-20-37-43 provides higher voltage switching capability (265V AC / 250V DC) compared to the MRPR-3-37-43 (140V AC / 200V DC). The MRPR-20-37-43 also has a reduced lower operating temperature limit (-20°C versus -40°C).

Q: Is the MRPR-20-37-43 suitable for applications originally designed for 140V AC / 200V DC operation?

A: Yes. The MRPR-20-37-43 is rated for higher voltages and will function correctly in applications operating at or below the original part's voltage specifications. No design changes are required.

Q: Are there any packaging differences between these parts?

A: The MRPR-3-37-43 is listed with packaging designation "-" while the MRPR-20-37-43 is supplied in bulk packaging. Both parts use identical through-hole axial termination suitable for standard PCB assembly processes.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the MRPR-3-37-43 and MRPR-20-37-43 are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, ensuring equivalent regulatory and environmental compliance.

Q: What should be considered when selecting between these parts for new designs?

A: For new designs, the MRPR-20-37-43 is the recommended choice due to its active product status, higher voltage margin, and current availability. The part is functionally equivalent to the obsolete MRPR-3-37-43 while offering improved design flexibility for voltage-sensitive applications.