LTP300 Polymeric PTC Resettable Fuse - Equivalent & Substitute Parts

Part Overview

The LTP300 is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., rated for 24V at 3A hold current with a 6.3A trip current. This component is designed for circuit protection in applications requiring automatic reset capability after fault conditions are cleared. The LTP300 is classified as obsolete, making identification of active equivalent parts essential for ongoing design support and procurement continuity.

Substiute Parts

LTP300

Littelfuse Inc.In Stock: 1146LTP300 Datasheet

Current PartRFQ

MF-LS300

Bourns Inc.In Stock: 1026MF-LS300 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LTP300 is determined by strict equivalence across the following electrical and mechanical parameters:

• Voltage rating: 24V maximum
• Hold current (Ih): 3A maximum
• Trip current (It): 6.3A
• Time to trip: 4 seconds
• Initial resistance (Ri): 15 mOhms minimum
• Post-trip resistance (R1): 55 mOhms maximum
• Operating temperature range: -40°C to 85°C
• Package type: Strap configuration
• Physical dimensions: 1.185" L x 0.522" W (30.10mm x 13.25mm)
• Thickness: 0.043" (1.10mm) maximum

The MF-LS300 from Bourns Inc. meets all specified electrical and mechanical parameters, establishing it as a direct functional equivalent.

Parameter Comparison

Engineering Selection Recommendations

The MF-LS300 is the direct equivalent for LTP300 replacement. Both components share identical electrical ratings and mechanical specifications across all critical parameters. The MF-LS300 offers the advantage of active product status, ensuring continued availability and supply chain support.

The MF-LS300 carries ROHS3 compliance, whereas the LTP300 is RoHS non-compliant. This distinction is relevant for applications subject to RoHS regulatory requirements. Both components maintain TUV certification; the MF-LS300 additionally carries cURus approval while the LTP300 includes CSA and UL approvals.

Frequently Asked Questions (FAQ)

Q: Can the MF-LS300 directly replace the LTP300 in existing designs?

A: Yes. The MF-LS300 meets all electrical and mechanical specifications of the LTP300, including voltage rating, hold current, trip current, time to trip, resistance characteristics, operating temperature range, and physical dimensions in strap package configuration.

Q: What are the key differences between these parts?

A: The primary differences are product status and regulatory compliance. The LTP300 is obsolete, while the MF-LS300 is active. The MF-LS300 is ROHS3 compliant; the LTP300 is not. Certification bodies differ slightly: MF-LS300 carries cURus and TUV; LTP300 carries CSA, TUV, and UL.

Q: Are there any package or dimensional considerations for substitution?

A: Both components use identical strap package configuration with matching dimensions of 1.185" L x 0.522" W (30.10mm x 13.25mm) and 0.043" (1.10mm) maximum thickness. No mechanical redesign is required for substitution.

Q: Which part should be selected for new designs?

A: The MF-LS300 should be selected for new designs due to its active product status and ROHS3 compliance, ensuring long-term availability and regulatory alignment.