LC303H2K NTC Thermistor 30kΩ Equivalent & Substitute Parts

Part Overview

The LC303H2K is an NTC thermistor manufactured by Littelfuse, designed for temperature sensing applications requiring a 30kΩ resistance at 25°C with a B value of 3810K. This component features an epoxy bead package with free-hanging leads and operates up to 150°C. The part is classified as obsolete, making identification of suitable equivalent components essential for ongoing system support and new design implementations.

Substiute Parts

LC303H2K

LittelfuseIn Stock: 806LC303H2K Datasheet

Current PartRFQ

701008

TE Connectivity Measurement SpecialtiesIn Stock: 1254701008 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LC303H2K is determined by the following critical parameters:

• Resistance Value: 30kΩ at 25°C (tolerance range 27kΩ–33kΩ for ±10%)
• B Value: 3810K (defines temperature-resistance characteristic curve)
• Operating Temperature: Maximum 150°C
• Package Configuration: Bead form factor with free-hanging leads
• Compliance: ROHS3 and EAR99 classification

The TE Connectivity Measurement Specialties part number 701008 meets these substitution criteria with matching resistance, B value, and operating temperature specifications. The substitute provides improved tolerance specifications and an extended lower temperature range while maintaining functional equivalence for the primary thermal sensing application.

Parameter Comparison

Engineering Selection Recommendations

The 701008 from TE Connectivity Measurement Specialties is a direct functional equivalent for the obsolete LC303H2K. Both components share identical resistance values, B value characteristics, and operating temperature maximums. The substitute maintains ROHS3 compliance and EAR99 classification, ensuring regulatory alignment.

The 701008 offers advantages including active product status with ongoing availability, tighter resistance tolerance, and extended lower temperature operating range (−40°C vs. unspecified lower limit). The longer lead wire length (76.20mm vs. 38.00mm) requires mechanical layout verification to ensure compatibility with existing mounting configurations.

Selection of the 701008 is appropriate for direct replacement in applications where the extended lead length does not create mechanical constraints and where the improved tolerance specifications provide system benefit.

Frequently Asked Questions (FAQ)

Q: Can the 701008 directly replace the LC303H2K in existing designs?

A: The 701008 provides functional equivalence based on matching resistance value, B value, and operating temperature specifications. Mechanical compatibility must be verified due to the longer lead wire length (76.20mm vs. 38.00mm). Circuit-level performance remains equivalent for temperature sensing applications.

Q: What is the significance of the B value in thermistor substitution?

A: The B value defines the temperature-resistance characteristic curve of an NTC thermistor. Matching B values (3810K in this case) ensure that both components produce identical resistance changes across the operating temperature range, maintaining calibration accuracy and system response characteristics.

Q: Does the tighter tolerance of the 701008 affect compatibility?

A: The 701008 tolerance specification of ±0.2°C is more restrictive than the LC303H2K tolerance of ±10%. This represents improved component consistency and does not create compatibility issues; systems designed for ±10% tolerance will function correctly with tighter tolerance components.

Q: Are there compliance considerations for this substitution?

A: Both components maintain ROHS3 compliance and EAR99 classification. No additional compliance verification is required for the substitution from a regulatory standpoint.

Q: What should be verified before implementing the 701008 substitute?

A: Verify that the longer lead wire length (76.20mm) accommodates the existing mechanical mounting configuration. Confirm that circuit-level thermal response requirements are met by the matching B value specification. Validate that the extended lower temperature range (−40°C) does not introduce unintended thermal sensing behavior in the application environment.