LTP340 Equivalent & Substitute Parts

Part Overview

The LTP340 is a polymeric PTC resettable fuse manufactured by Littelfuse, rated for 24V at 3.4A hold current. This component is classified as obsolete, making identification of equivalent substitute parts essential for ongoing system support and new design implementations. The LTP340 belongs to the PolySwitch® LTP series and is designed for applications requiring automatic overcurrent protection with resettable functionality in strap package configuration.

Substiute Parts

LTP340

LittelfuseIn Stock: 788LTP340 Datasheet

Current PartRFQ

MF-LS340

Bourns Inc.In Stock: 6578MF-LS340 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LTP340 is determined by strict equivalence across electrical and mechanical parameters. The following criteria establish valid substitution:

Electrical Parameters (Critical):

• Voltage rating: 24V maximum
• Hold current (Ih): 3.4A maximum
• Trip current (It): 6.8A
• Maximum current capacity: 100A
• Time to trip: 5 seconds
• Initial resistance (Ri): 16 mOhms minimum
• Post-trip resistance (R1): 50 mOhms maximum

Mechanical Parameters (Critical):

• Package type: Strap configuration
• Physical dimensions: 0.984" L x 0.604" W (25.00mm x 15.35mm)
• Thickness: 0.039" (1.00mm) maximum
• Mounting type: User defined

Environmental Parameters:

• Operating temperature range: -40°C to 85°C
• Polymeric PTC type construction

The MF-LS340 manufactured by Bourns Inc. meets all specified electrical and mechanical parameters and qualifies as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

The MF-LS340 from Bourns Inc. is the qualified substitute for the obsolete LTP340. Selection is based on the following factors:

Electrical Equivalence: All electrical parameters match exactly, including voltage rating, hold current, trip current, time to trip, and resistance specifications.

Mechanical Compatibility: Physical dimensions, package configuration, and mounting type are identical, ensuring direct replacement in existing designs.

Product Status: The MF-LS340 is active in production, providing long-term availability and supply chain stability compared to the obsolete LTP340.

Compliance Advantage: The MF-LS340 meets ROHS3 compliance requirements, whereas the LTP340 is RoHS non-compliant. This provides regulatory advantage for new designs and updated systems.

Certification: Both components carry relevant approval agencies (CSA, TUV, UL for LTP340; cURus, TUV for MF-LS340), supporting use in regulated applications.

Frequently Asked Questions (FAQ)

Q: Can the MF-LS340 be used as a direct replacement for the LTP340 in existing designs?

A: Yes. The MF-LS340 meets all electrical and mechanical specifications of the LTP340, including voltage rating, current ratings, resistance characteristics, operating temperature range, and physical dimensions. Direct substitution is supported.

Q: What is the primary reason to substitute the LTP340?

A: The LTP340 is classified as obsolete. The MF-LS340 provides equivalent functionality with active production status and improved RoHS3 compliance.

Q: Are there differences in package or mounting between these parts?

A: No. Both components use identical strap package configuration with matching physical dimensions of 0.984" L x 0.604" W (25.00mm x 15.35mm) and 0.039" (1.00mm) maximum thickness.

Q: Do the electrical characteristics differ between LTP340 and MF-LS340?

A: No. Hold current, trip current, maximum current capacity, time to trip, and resistance specifications are identical across both components.

Q: What is the operating temperature range for the MF-LS340?

A: The MF-LS340 operates across -40°C to 85°C, matching the LTP340 specification.

Q: Is the MF-LS340 RoHS compliant?

A: Yes. The MF-LS340 is ROHS3 compliant, providing regulatory advantage over the RoHS non-compliant LTP340.