LC102F2K NTC Thermistor Equivalent & Substitute Parts

Part Overview

The LC102F2K is an NTC thermistor manufactured by Littelfuse Inc., designed as a 1kΩ bead-type temperature sensor with an epoxy package. This component is classified as obsolete, indicating discontinued production and limited availability in the market. The part operates across a temperature range up to 150°C and features a B0/50 value of 3419K with ±10% resistance tolerance.

Due to its obsolete status, identifying functionally equivalent substitute parts is essential for system redesign, maintenance, and procurement continuity. Substitute parts must maintain electrical compatibility through matching resistance values, tolerance specifications, and thermal characteristics while accommodating potential differences in physical form factor and mounting configuration.

Substiute Parts

LC102F2K

Littelfuse Inc.In Stock: 1003LC102F2K Datasheet

Current PartRFQ

140-102FAG-RB1

Honeywell Sensing and Productivity SolutionsIn Stock: 1085140-102FAG-RB1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LC102F2K is determined by the following critical parameters:

• Resistance Value: Must be 1kΩ at 25°C
• Resistance Tolerance: Must be ±10% or tighter
• B-Value Characteristics: B0/50 value must be within acceptable thermal response range (3419K–3420K represents equivalent thermal behavior)
• Lead Wire Length: 1.50" (38.00mm) maintains mechanical compatibility
• Moisture Sensitivity: MSL 1 (Unlimited) ensures no moisture-related constraints
• Regulatory Compliance: RoHS and REACH compliance status must be maintained or improved

The substitute part 140-102FAG-RB1 meets these criteria through matching electrical specifications and enhanced compliance certifications. Physical form factor differences (disc vs. bead) and mounting configuration changes (through-hole vs. free-hanging) are acceptable provided the electrical performance and lead geometry remain compatible with the application circuit.

Parameter Comparison

Engineering Selection Recommendations

The 140-102FAG-RB1 from Honeywell Sensing and Productivity Solutions qualifies as a direct electrical substitute for the obsolete LC102F2K based on matched resistance values, tolerance specifications, and B-value thermal characteristics. Both components maintain identical lead wire length (38.00mm) and moisture sensitivity classification.

Key considerations for selection:

Electrical Compatibility: The B0/50 values differ by 1K (3419K vs. 3420K), representing negligible thermal response variance within typical application tolerances. The substitute provides specified B-value tolerance (±2.3%), offering improved thermal accuracy definition compared to the original part.

Operating Temperature: The LC102F2K supports operation to 150°C, while the 140-102FAG-RB1 is rated to 125°C maximum. Applications requiring temperatures above 125°C require verification that the substitute meets thermal requirements.

Product Status and Availability: The substitute part maintains active production status with confirmed inventory (992 units), ensuring procurement reliability and long-term supply continuity.

Regulatory Compliance: Both components satisfy RoHS and REACH requirements. The substitute maintains equivalent or superior compliance posture.

Physical Form Factor: The transition from bead to disc package and from free-hanging to through-hole mounting requires circuit board layout verification to confirm mechanical fit and electrical connection compatibility.

Frequently Asked Questions (FAQ)

Q: Can the 140-102FAG-RB1 replace the LC102F2K in all applications?

A: Electrical substitution is valid for applications operating within the 140-102FAG-RB1 temperature range (-60°C to 125°C). Applications requiring operation above 125°C require alternative solutions. Physical mounting differences (through-hole vs. free-hanging) necessitate circuit board design verification.

Q: What is the significance of the B-value difference (3419K vs. 3420K)?

A: The 1K difference represents approximately 0.03% variance in thermal response characteristics. This difference is negligible for most temperature sensing applications and falls within typical measurement and calibration tolerances.

Q: Are there any compliance concerns with substitution?

A: Both parts maintain RoHS and REACH compliance. No regulatory barriers exist for substitution from a compliance perspective.

Q: How does the package change from bead to disc affect circuit performance?

A: Electrical performance remains equivalent. Physical package differences affect thermal time constant, mechanical mounting, and spatial requirements. Circuit board layout must accommodate the disc form factor and through-hole mounting configuration.

Q: Is the 140-102FAG-RB1 available in the same packaging format as the LC102F2K?

A: The substitute is supplied in bulk packaging, whereas original packaging format is not specified in available data. Confirm packaging requirements with the supplier for production and assembly compatibility.