MICROSMD250LR-A-2 Equivalent & Substitute Parts

Part Overview

The MICROSMD250LR-A-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse Inc., rated for 6V maximum voltage with a 2.5A hold current. This component is designed for surface mount applications in the 1210 (3225 Metric) package format with a concave profile. The part is currently listed as obsolete, making identification of suitable substitute components essential for ongoing design support and production continuity.

Substiute Parts

MICROSMD250LR-A-2

Littelfuse Inc.In Stock: 9105MICROSMD250LR-A-2 Datasheet

Current PartRFQ

1210L260SLYR

LittelfuseIn Stock: 7841210L260SLYR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MICROSMD250LR-A-2 is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Voltage rating must equal or exceed 6V maximum
• Current hold (Ih) rating must accommodate the circuit's normal operating current without nuisance trips
• Current trip (It) threshold must provide appropriate overcurrent protection
• Resistance characteristics must not introduce unacceptable voltage drop or thermal effects

Mechanical & Package Compatibility Requirements:

• Surface mount mounting type
• 1210 (3225 Metric) package footprint with concave profile
• Physical dimensions must match PCB layout constraints
• Thickness must not exceed 0.039" (1.00mm) for board clearance

Regulatory & Environmental Requirements:

• RoHS3 compliance
• Appropriate moisture sensitivity level for storage and handling
• Recognized approval agencies (CSA, UL, cURus, TUV)

The substitute part 1210L260SLYR meets these criteria while offering active product status and improved specifications.

Parameter Comparison

Engineering Selection Recommendations

The 1210L260SLYR is the manufacturer-recommended substitute for the obsolete MICROSMD250LR-A-2. Both components share identical voltage ratings (6V), package geometry (1210 concave), and maximum current capacity (50A). The substitute maintains RoHS3 compliance and is manufactured by the same supplier within the LoRho series family.

The 1210L260SLYR offers active product status, ensuring long-term availability and supply chain stability. The component carries cURus and TUV certifications, providing broader regulatory recognition compared to the original part's CSA and UL approvals. The improved moisture sensitivity level (MSL 1 vs. 2A) reduces handling and storage constraints.

Electrical parameter differences are minor: the substitute's 2.6A hold current is marginally higher than the original 2.5A, while the trip current (5A vs. 5.2A) and trip time (4s vs. 5s) are slightly lower. These variations remain within acceptable tolerance for polymeric PTC fuse applications. The lower initial resistance (3 mOhms vs. 5 mOhms) reduces voltage drop during normal operation.

Physical profile improvement (0.70mm vs. 1.00mm thickness) provides additional PCB layout flexibility without affecting footprint compatibility.

Frequently Asked Questions (FAQ)

Q: Can the 1210L260SLYR be used as a direct replacement for MICROSMD250LR-A-2?

A: Yes. Both components share identical voltage ratings, package dimensions, and mounting type. The substitute is the manufacturer-recommended equivalent and maintains electrical and mechanical compatibility.

Q: What are the key electrical differences between these parts?

A: The 1210L260SLYR has a marginally higher hold current (2.6A vs. 2.5A), slightly lower trip current (5A vs. 5.2A), and faster trip time (4s vs. 5s). Initial resistance is lower (3 mOhms vs. 5 mOhms). These differences are typical within polymeric PTC fuse product families and do not prevent substitution in standard applications.

Q: Are there any PCB layout considerations?

A: The 1210L260SLYR is thinner (0.70mm vs. 1.00mm), which may improve clearance in space-constrained designs. Footprint dimensions remain identical, so no PCB redesign is required.

Q: What is the impact of the different moisture sensitivity levels?

A: The substitute's MSL 1 rating (unlimited shelf life) is superior to the original MSL 2A (4-week limit). This reduces storage and handling constraints and improves component shelf stability.

Q: Are regulatory certifications compatible?

A: The substitute carries cURus and TUV certifications versus the original's CSA and UL approvals. Both certification sets are recognized for polymeric PTC fuse applications. The substitute's broader certification profile supports wider market acceptance.

Q: What is the availability status of each part?

A: The MICROSMD250LR-A-2 is obsolete with limited remaining inventory. The 1210L260SLYR is active and in current production, ensuring reliable long-term supply.