MICROSMD450LR-C-2 Equivalent & Substitute Parts

Part Overview

The MICROSMD450LR-C-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse Inc., rated for 12V at 4.5A hold current in a 1210 (3225 Metric) surface mount package. This component is classified as Obsolete, making identification of suitable substitute parts essential for ongoing design support and procurement continuity. The PolySwitch® LoRho series device provides overcurrent protection through polymeric PTC technology with automatic reset capability after fault condition removal.

Substiute Parts

MICROSMD450LR-C-2

Littelfuse Inc.In Stock: 2181MICROSMD450LR-C-2 Datasheet

Current PartRFQ

1210L500/12SLWR

Littelfuse Inc.In Stock: 39981210L500/12SLWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MICROSMD450LR-C-2 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Voltage rating: 12V maximum (substitute must equal or exceed)
• Package / Case: 1210 (3225 Metric), Concave surface mount form factor
• Mounting Type: Surface mount technology
• Regulatory compliance: cURus and TUV approval

Functional Compatibility Criteria:

• Current hold (Ih) rating: Must accommodate the protected circuit's normal operating current
• Current trip (It) rating: Must provide appropriate overcurrent threshold
• Polymeric PTC technology: Automatic reset capability after fault removal

The substitute part 1210L500/12SLWR meets all mandatory compatibility criteria and maintains the same package footprint, voltage rating, and regulatory approvals. The substitute operates within the same 12V system voltage and uses identical surface mount packaging, ensuring direct PCB compatibility.

Parameter Comparison

Engineering Selection Recommendations

The 1210L500/12SLWR is the designated substitute for the obsolete MICROSMD450LR-C-2. Both components share identical voltage ratings (12V), package geometry (1210 Concave), and regulatory certifications (cURus, TUV). The substitute maintains ROHS3 compliance and is currently in active production status, ensuring long-term availability and supply chain continuity.

The substitute exhibits a higher current hold rating (5.0A versus 4.5A) and improved lower operating temperature range (-40°C versus -20°C), providing enhanced performance margins in 12V protection circuits. Both components employ polymeric PTC technology with automatic reset functionality, maintaining functional equivalence in overcurrent protection applications.

Frequently Asked Questions (FAQ)

Q: Can the 1210L500/12SLWR directly replace the MICROSMD450LR-C-2 on existing PCBs?

A: Yes. Both components use identical 1210 (3225 Metric) Concave surface mount packaging with matching footprints and land patterns. No PCB layout modifications are required.

Q: What is the difference in current hold ratings between these parts?

A: The main part (MICROSMD450LR-C-2) has a 4.5A hold current, while the substitute (1210L500/12SLWR) has a 5.0A hold current. The substitute provides 0.5A additional capacity, suitable for circuits requiring the original 4.5A protection threshold.

Q: Are both parts compliant with the same regulatory standards?

A: Yes. Both components carry cURus and TUV approvals and are ROHS3 compliant, meeting identical regulatory requirements for 12V protection applications.

Q: Why is the substitute part in Active status while the main part is Obsolete?

A: The MICROSMD450LR-C-2 has been discontinued by the manufacturer. The 1210L500/12SLWR represents the current production equivalent within the Littelfuse LoRho polymeric PTC fuse portfolio, ensuring ongoing availability and support.

Q: Does the substitute operate across the same temperature range?

A: The substitute operates across a wider temperature range (-40°C to 85°C) compared to the main part (-20°C to 85°C), providing improved performance in lower temperature environments.

Q: What is the significance of the Moisture Sensitivity Level difference?

A: The substitute has MSL 1 (Unlimited shelf life), compared to the main part's MSL 2A (4 weeks). This indicates improved moisture resistance and longer storage capability without special handling requirements.