MS 750 Equivalent & Substitute Parts

Part Overview

The MS 750 is a 750 mA board mount axial fuse rated for 125 V AC/DC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement continuity. The MS 750 serves as a protective device in through-hole applications requiring slow-blow response characteristics and compact axial packaging.

Substiute Parts

MS 750

Bel Fuse Inc.In Stock: 807MS 750 Datasheet

Current PartRFQ

0473.750MRT1L

Littelfuse Inc.In Stock: 39480473.750MRT1L Datasheet

DirectRFQ

0473.750YRT1L

Littelfuse Inc.In Stock: 322150473.750YRT1L Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MS 750 is determined by strict equivalence across the following critical parameters:

• Current Rating: 750 mA (exact match required)
• Voltage Rating: 125 V AC and 125 V DC (exact match required)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Through Hole (exact match required)
• Fuse Type: Board Mount, Cartridge Style Excluded (exact match required)
• Package / Case: Axial (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

The substitute parts identified below meet all of these criteria. Both alternatives are manufactured by Littelfuse Inc. under the PICO® II 473 series and are classified as active products, providing long-term availability and supply chain stability compared to the obsolete MS 750.

Parameter Comparison

Engineering Selection Recommendations

Both 0473.750MRT1L and 0473.750YRT1L are functionally equivalent substitutes for the MS 750. Selection between these two alternatives should be based on the following factors:

Availability and Supply Chain: The 0473.750YRT1L maintains significantly higher inventory levels (32,200 pcs) compared to 0473.750MRT1L (3,894 pcs), making it the preferred choice for applications requiring assured long-term supply.

Regulatory Compliance: Both substitute parts hold CSA and UR certifications. The MS 750 carries additional CE and cURus approvals. Designs requiring CE or cURus compliance should be evaluated against the substitute certifications to ensure regulatory requirements are met.

Environmental Compliance: Both Littelfuse alternatives are ROHS3 compliant, providing enhanced environmental compliance compared to the MS 750, for which RoHS status was not specified.

Physical Dimensions: The substitute parts exhibit a slightly larger diameter (0.135" vs. 0.125") while maintaining the same length. PCB layout and mechanical clearance must be verified before implementation.

Frequently Asked Questions (FAQ)

Q: Can 0473.750MRT1L and 0473.750YRT1L be used interchangeably with the MS 750?

A: Both parts meet all critical electrical and mechanical parameters required for substitution: 750 mA current rating, 125 V AC/DC voltage rating, slow-blow response, through-hole mounting, and axial packaging. Physical dimensions differ slightly in diameter; PCB layout verification is required.

Q: What is the difference between 0473.750MRT1L and 0473.750YRT1L?

A: Both parts are electrically and mechanically identical, belonging to the same PICO® II 473 series. The primary distinction is inventory availability, with 0473.750YRT1L offering substantially higher stock levels.

Q: Are there any compliance considerations when substituting the MS 750?

A: The MS 750 carries CE, CSA, and cURus certifications. Substitute parts hold CSA and UR certifications. Applications requiring CE or cURus compliance should confirm that substitute certifications satisfy design requirements. Both substitutes are ROHS3 compliant.

Q: Will the slightly larger diameter of the substitute parts affect PCB compatibility?

A: The substitute parts have a diameter of 0.135" compared to the MS 750's 0.125". PCB hole sizing and component placement must be verified to ensure mechanical fit within the existing design layout.

Q: What is the significance of the different Melting I²t values?

A: The MS 750 has a Melting I²t of 0.46, while both substitutes have 0.76. This parameter affects thermal response characteristics. Applications with specific thermal protection requirements should confirm that the substitute's thermal characteristics are acceptable for the intended circuit protection function.

Q: Are the substitute parts suitable for long-term production use?

A: Yes. Both 0473.750MRT1L and 0473.750YRT1L are classified as active products with established supply chains, making them suitable for ongoing production and design continuity beyond the obsolete MS 750.