MF-USML400-2 PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The MF-USML400-2 is a Polymeric PTC Resettable Fuse manufactured by Bourns Inc., rated for 6V at 4A hold current in a 1210 (3225 Metric) surface mount package. This component is classified as Obsolete, making identification of suitable substitutes essential for ongoing design support and production continuity. The part operates across the industrial temperature range of -40°C to 85°C and carries cURus and TUV approvals.

Substiute Parts

MF-USML400-2

Bourns Inc.In Stock: 1033MF-USML400-2 Datasheet

Current PartRFQ

MF-USML400/6-2

Bourns Inc.In Stock: 4536MF-USML400/6-2 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The MF-USML400/6-2 qualifies as a direct substitute based on the following critical parameters:

Voltage rating (6V maximum) is identical, ensuring compatibility with the same circuit voltage specifications. Current hold rating (4A) and trip current (8A) match the original part, maintaining the same protection threshold. Both components use identical 1210 (3225 Metric) surface mount packaging with concave geometry, confirming mechanical and footprint compatibility. Operating temperature range (-40°C to 85°C) is identical across both parts. Both parts carry cURus and TUV certifications and maintain ROHS3 compliance.

The MF-USML400/6-2 is classified as Active product status, providing long-term availability and supply chain stability compared to the Obsolete MF-USML400-2.

Parameter Comparison

Engineering Selection Recommendations

The MF-USML400/6-2 is the appropriate substitute for the obsolete MF-USML400-2. Both parts maintain identical electrical ratings for voltage, hold current, and trip current, with matching surface mount 1210 package geometry. The substitute part carries Active product status, ensuring continued availability and supply chain support.

Both components hold cURus and TUV certifications and comply with ROHS3 requirements, meeting regulatory and compliance standards for industrial applications. The MF-USML400/6-2 is available in Tape & Reel packaging, supporting automated assembly processes.

Minor differences in time-to-trip (5s versus 2s) and post-trip resistance values are within acceptable tolerance for PTC resettable fuse applications and do not preclude substitution in standard circuit protection scenarios.

Frequently Asked Questions (FAQ)

Q: Can the MF-USML400/6-2 be used as a direct replacement for the MF-USML400-2?

A: Yes. Both parts share identical voltage (6V), hold current (4A), trip current (8A), and 1210 surface mount package specifications. The substitute is electrically and mechanically compatible.

Q: What is the difference in time-to-trip between these parts?

A: The MF-USML400-2 trips in 2 seconds, while the MF-USML400/6-2 trips in 5 seconds. This difference reflects manufacturing variations in PTC material characteristics and does not affect substitution suitability for standard protection applications.

Q: Are both parts certified to the same standards?

A: Yes. Both the MF-USML400-2 and MF-USML400/6-2 carry cURus and TUV approvals and comply with ROHS3 requirements.

Q: What packaging options are available for the substitute part?

A: The MF-USML400/6-2 is supplied in Tape & Reel (TR) packaging, suitable for automated pick-and-place assembly.

Q: Why is the MF-USML400-2 listed as Obsolete?

A: Obsolete status indicates the part is no longer in active production. The MF-USML400/6-2 provides continued access to equivalent functionality with Active product status and improved supply availability.