Equivalent & Substitute Parts for 1812L370SLPR

Part Overview

The 1812L370SLPR is a polymeric PTC resettable fuse manufactured by Littelfuse Inc., designed for surface mount applications in the 1812 (4532 Metric) package format. This component provides overcurrent protection with a 6V maximum voltage rating and 3.7A hold current specification. The part is classified as obsolete, necessitating identification of active equivalent alternatives for new designs and ongoing production requirements.

Substiute Parts

1812L370SLPR

Littelfuse Inc.In Stock: 6931812L370SLPR Datasheet

Current PartRFQ

1812L350SLPR

Littelfuse Inc.In Stock: 58201812L350SLPR Datasheet

MFR RecommendedRFQ

PTSLR18126V370

Eaton - Electronics DivisionIn Stock: 1473PTSLR18126V370 Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 1812L370SLPR is determined by the following critical parameters:

Mandatory Matching Parameters:

• Voltage - Max: 6V
• Package / Case: 1812 (4532 Metric), Concave
• Mounting Type: Surface Mount
• Operating Temperature Range: -40°C ~ 85°C
• Approval Agencies: cURus, TUV certification

Allowable Variation Parameters:

• Current - Hold (Ih) (Max): ±0.2A tolerance
• Current - Trip (It): ±0.2A tolerance
• Time to Trip: ±3s tolerance
• Resistance - Post Trip (R1) (Max): ±2 mOhms tolerance
• Product Status: Active alternatives preferred over obsolete
• Moisture Sensitivity Level: MSL 1 or MSL 2A acceptable
• RoHS Compliance: ROHS3 Compliant required

Two substitute parts meet these criteria with documented parametric equivalence or manufacturer recommendation.

Parameter Comparison

Engineering Selection Recommendations

1812L350SLPR (Littelfuse Inc.) - MFR Recommended Substitute

This part is the manufacturer-recommended alternative, maintaining identical physical dimensions, voltage rating, and package specifications. The current hold rating is 4.6A versus 3.7A on the original, representing a 0.2A reduction within acceptable tolerance. The trip current decreases from 9.1A to 8.1A, and time to trip extends from 2s to 5s. Post-trip resistance increases to 20 mOhms from 18 mOhms. The part carries active product status with unlimited moisture sensitivity rating and full regulatory compliance (cURus, TUV, ROHS3, REACH Unaffected).

PTSLR18126V370 (Eaton - Electronics Division) - Parametric Equivalent

This part provides parametric equivalence with identical current hold (3.7A), trip current (9.1A), time to trip (2s), and post-trip resistance (18 mOhms) specifications. Physical dimensions, voltage rating, and package format match exactly. The part is active with full regulatory compliance. Moisture sensitivity is rated MSL 2A (4 weeks) versus MSL 1 on the original, requiring controlled storage conditions during handling.

Both substitutes satisfy mandatory electrical and mechanical compatibility requirements. Selection between them depends on circuit performance requirements regarding trip timing and current thresholds, as well as supply chain and storage condition considerations.

Frequently Asked Questions (FAQ)

Q: Can 1812L350SLPR be used as a direct replacement for 1812L370SLPR?

A: Yes, within the allowable parameter tolerances. The 1812L350SLPR is the manufacturer-recommended substitute. The 0.2A reduction in hold current and 1A reduction in trip current represent the primary functional differences. Applications requiring the exact 3.7A hold current specification should evaluate circuit performance impact.

Q: What is the difference between the two substitute parts?

A: The 1812L350SLPR (Littelfuse) differs from PTSLR18126V370 (Eaton) primarily in current hold rating (4.6A vs. 3.7A) and time to trip (5s vs. 2s). The PTSLR18126V370 provides parametric equivalence to the original 1812L370SLPR. The 1812L350SLPR is the official manufacturer recommendation. Moisture sensitivity differs: MSL 1 (Unlimited) for 1812L350SLPR versus MSL 2A (4 weeks) for PTSLR18126V370.

Q: Are the physical dimensions identical across all three parts?

A: Yes. All three parts use the 1812 (4532 Metric) package with concave configuration, measuring 0.179" L x 0.128" W (4.55mm x 3.24mm) with maximum thickness of 0.028" (0.70mm). Surface mount compatibility is identical.

Q: What does MSL 2A mean for the Eaton part?

A: Moisture Sensitivity Level 2A indicates the component requires controlled storage conditions with maximum exposure of 4 weeks at 30°C and 60% relative humidity before soldering. MSL 1 (Unlimited) on the Littelfuse alternatives allows indefinite storage without moisture control requirements.

Q: Do all parts carry the same regulatory certifications?

A: Yes. All three parts are cURus and TUV approved, ROHS3 compliant, and REACH unaffected. Regulatory compliance is equivalent across all options.

Q: Which substitute should be selected for new designs?

A: Selection depends on circuit requirements. For exact parametric match to the original 1812L370SLPR, use PTSLR18126V370 (Eaton). For manufacturer-recommended active alternative with simplified supply chain, use 1812L350SLPR (Littelfuse). Both are active products with full regulatory compliance.