MF-LR190S Polymeric PTC Resettable Fuse Equivalent & Substitute Parts

Part Overview

The MF-LR190S is a polymeric PTC resettable fuse manufactured by Bourns Inc. in the Multifuse® MF-LR series. This component is rated for 15V maximum voltage with a 1.9A hold current and 3.9A trip current, designed for strap-mounted applications. The part is currently listed as obsolete, making identification of equivalent and substitute components essential for ongoing system support and procurement planning.

Substiute Parts

MF-LR190S

Bourns Inc.In Stock: 970MF-LR190S Datasheet

Current PartRFQ

MF-LR190

Bourns Inc.In Stock: 6715MF-LR190 Datasheet

DirectRFQ

LR4-190F

Littelfuse Inc.In Stock: 2515LR4-190F Datasheet

SimilarRFQ

LR4-190SF

Littelfuse Inc.In Stock: 748LR4-190SF Datasheet

SimilarRFQ

LR4-260SF

Littelfuse Inc.In Stock: 2958LR4-260SF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MF-LR190S is determined by strict equivalence across the following critical parameters:

• Voltage rating: 15V maximum
• Hold current (Ih): 1.9A maximum
• Trip current (It): 3.9A
• Package type: Strap mounting
• Polymeric PTC resettable fuse technology
• Operating temperature range: -40°C to 85°C
• RoHS3 compliance

Parts are grouped into two categories:

Direct Equivalent (MF-LR190): Identical electrical specifications and performance characteristics. Differs only in product status (active vs. obsolete) and packaging format (bulk vs. strap).

Similar Substitutes (LR4-190F, LR4-190SF, LR4-260SF): Manufactured by Littelfuse Inc. under the PolySwitch® LR4 series. LR4-190F and LR4-190SF maintain identical hold and trip current ratings. LR4-260SF operates at 2.6A hold current and 5.8A trip current, representing a higher current rating variant within the same voltage class and package family.

Parameter Comparison

Engineering Selection Recommendations

MF-LR190 (Direct Equivalent): This is the primary replacement for the obsolete MF-LR190S. It maintains identical electrical specifications, operating parameters, and physical dimensions. The part is manufactured by the same supplier (Bourns Inc.) and carries active product status with higher inventory availability (6654 pcs vs. 902 pcs). Both parts meet ROHS3 compliance and carry cURus and TUV approvals. Selection of MF-LR190 eliminates obsolescence risk while preserving full functional compatibility.

LR4-190F (Cross-Manufacturer Equivalent): This Littelfuse Inc. component provides electrical equivalence with identical hold current (1.9A), trip current (3.9A), and voltage rating (15V). Physical dimensions are nearly identical with minimal width variance (5.20mm vs. 5.05mm). The part carries expanded regulatory approvals (CSA, TUV, UL) and active product status. Inventory availability is substantial (2475 pcs). This option is suitable when Littelfuse components are preferred or when supply chain diversification is required.

LR4-190SF (Cross-Manufacturer Equivalent): This variant maintains electrical equivalence but features increased physical length (24.00mm vs. 21.00mm). It is suitable only when mechanical space permits the larger footprint. Product status is active with moderate inventory (652 pcs).

LR4-260SF (Higher Current Variant): This part operates at 2.6A hold current and 5.8A trip current, representing a higher current rating. It is not a direct substitute for the MF-LR190S and should be selected only when circuit requirements demand increased current capacity. The lower initial resistance (20 mOhms vs. 39 mOhms) and post-trip resistance (63 mOhms vs. 102 mOhms) indicate different thermal and electrical characteristics. Use only when system design specifically requires these parameters.

Frequently Asked Questions (FAQ)

Q: Can MF-LR190 be used as a direct replacement for MF-LR190S?

A: Yes. MF-LR190 is a direct equivalent with identical electrical specifications, voltage rating, current ratings, and operating temperature range. The only differences are product status (active vs. obsolete) and packaging format (bulk vs. strap). No circuit modifications are required.

Q: What is the difference between Bourns Multifuse® and Littelfuse PolySwitch® components?

A: Both are polymeric PTC resettable fuses with equivalent electrical performance when specifications match. The primary differences are manufacturer, regulatory approvals, and supply chain. Littelfuse components (LR4 series) carry CSA and UL approvals in addition to TUV, while Bourns components carry cURus and TUV approvals.

Q: Can LR4-190F replace MF-LR190S in all applications?

A: LR4-190F provides electrical equivalence with identical hold and trip currents. Physical dimensions are nearly identical (width difference of 0.15mm). The part is suitable for replacement in applications where Littelfuse components are acceptable and where the minor dimensional variance does not create mechanical constraints.

Q: Why is LR4-260SF listed as a similar substitute if it has different current ratings?

A: LR4-260SF is listed as a similar substitute because it operates within the same voltage class (15V), uses identical strap packaging, and shares the same polymeric PTC technology. However, the 2.6A hold current and 5.8A trip current represent a higher current rating. This part is suitable only when circuit requirements specifically demand increased current capacity and is not a direct replacement for 1.9A applications.

Q: Are there mechanical compatibility concerns when substituting between these parts?

A: Minor dimensional variations exist. MF-LR190 and LR4-190F are nearly identical (width difference of 0.15mm). LR4-190SF is longer (24.00mm vs. 21.00mm). LR4-260SF is slightly longer (22.00mm vs. 21.00mm). Verify that mechanical mounting space accommodates these variations before selection.

Q: What regulatory approvals should I verify for my application?

A: MF-LR190S and MF-LR190 carry cURus and TUV approvals. LR4-190F and LR4-260SF carry CSA, TUV, and UL approvals. Verify that the selected part meets all regulatory requirements for your specific application and geographic market.

Q: Is there a difference in resistance characteristics between these parts?

A: MF-LR190S, MF-LR190, and LR4-190F share identical initial resistance (39 mOhms minimum) and post-trip resistance (102 mOhms maximum). LR4-260SF has lower resistance values (20 mOhms initial, 63 mOhms post-trip) due to its higher current rating. These differences affect thermal behavior and should be considered in circuit design.