LR4-190SLF Polymeric PTC Resettable Fuse - Equivalent & Substitute Parts

Part Overview

The LR4-190SLF is an active polymeric PTC resettable fuse manufactured by Littelfuse Inc. in the PolySwitch® LR4 series. This component provides overcurrent protection with a 15V maximum voltage rating and 1.9A hold current specification. The device is designed for user-defined strap mounting applications and operates across a temperature range of -40°C to 85°C. Finding equivalent substitute parts is necessary to ensure supply chain flexibility, optimize inventory management, and maintain design continuity when the primary part becomes unavailable.

Substiute Parts

LR4-190SLF

Littelfuse Inc.In Stock: 1191LR4-190SLF Datasheet

Current PartRFQ

MF-LR190

Bourns Inc.In Stock: 6715MF-LR190 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LR4-190SLF is determined by strict alignment of electrical and mechanical parameters. The critical parameters that define interchangeability are:

• Voltage - Max: 15V
• Current - Hold (Ih) (Max): 1.9 A
• Current - Trip (It): 3.9 A
• Current - Max: 100 A
• Time to Trip: 5 s
• Resistance - Initial (Ri) (Min): 39 mOhms
• Resistance - Post Trip (R1) (Max): 102 mOhms
• Operating Temperature: -40°C ~ 85°C
• Type: Polymeric
• Package / Case: Strap
• RoHS Status: ROHS3 Compliant

The MF-LR190 manufactured by Bourns Inc. meets all specified electrical parameters and environmental requirements, making it a direct functional equivalent for the LR4-190SLF.

Parameter Comparison

Engineering Selection Recommendations

Both the LR4-190SLF and MF-LR190 are active products with full regulatory compliance. The LR4-190SLF carries CSA, TUV, and UL approvals, while the MF-LR190 carries cURus and TUV approvals. Both components are ROHS3 compliant and carry EAR99 ECCN classification. Selection between these parts should be based on supply availability, packaging requirements (Littelfuse offers standard packaging while Bourns offers bulk packaging), and existing design qualification with either manufacturer's series.

Frequently Asked Questions (FAQ)

Q: Can the MF-LR190 directly replace the LR4-190SLF in existing designs?

A: Yes. The MF-LR190 meets all specified electrical parameters, operating temperature range, and mechanical package requirements. Both components are polymeric PTC resettable fuses with identical hold current, trip current, and resistance specifications.

Q: Are there dimensional differences between these parts?

A: Minor dimensional variations exist. The LR4-190SLF measures 0.945" L x 0.205" W (24.00mm x 5.20mm), while the MF-LR190 measures 0.827" L x 0.199" W (21.00mm x 5.05mm). Both share the same 0.039" (1.00mm) maximum thickness and strap package configuration. Verify mechanical fit within your application before implementation.

Q: What are the regulatory compliance differences?

A: The LR4-190SLF holds CSA, TUV, and UL certifications. The MF-LR190 holds cURus and TUV certifications. Both are ROHS3 compliant. Confirm that the substitute part's certification set meets your application requirements.

Q: Which part should I select for new designs?

A: Selection depends on supply chain strategy and existing qualifications. Both parts are active products with equivalent electrical performance. Consider manufacturer availability, lead times, and packaging preferences (standard vs. bulk) for your procurement needs.

Q: Are there inventory considerations?

A: The LR4-190SLF has 1131 pieces in stock, while the MF-LR190 has 6654 pieces available. Availability may influence short-term sourcing decisions.