LC502J2K NTC Thermistor 5kΩ Bead - Equivalent & Substitute Parts

Part Overview

The LC502J2K is an NTC thermistor manufactured by Littelfuse Inc., designed as a 5kΩ bead-type temperature sensor with epoxy packaging. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and component procurement. The part operates across a temperature range up to 150°C and is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1).

Substiute Parts

LC502J2K

Littelfuse Inc.In Stock: 843LC502J2K Datasheet

Current PartRFQ

701007

TE Connectivity Measurement SpecialtiesIn Stock: 2287701007 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LC502J2K is determined by the following critical parameters:

• Nominal Resistance: 5kΩ at 25°C (tolerance range 4.5kΩ to 5.5kΩ for ±10%)
• B-Value Thermal Coefficient: B0/50 = 3892K (defines temperature-resistance curve)
• Operating Temperature Range: Maximum 150°C
• Package Configuration: Bead form factor with free-hanging leads
• Compliance Standards: ROHS3 compliance required

The substitute part 701007 (TE Connectivity Measurement Specialties) meets these substitution criteria through matching nominal resistance (5kΩ), compatible B-value specification (B0/50 = 3891K, within thermal curve tolerance), extended operating range (-55°C to 150°C), and equivalent ROHS3 compliance status.

Parameter Comparison

Engineering Selection Recommendations

The 701007 (TE Connectivity Measurement Specialties) is the qualified substitute for the obsolete LC502J2K based on the following engineering criteria:

• Electrical Equivalence: Nominal 5kΩ resistance with B0/50 thermal coefficient of 3891K provides functional thermal response matching within acceptable tolerance margins for NTC thermistor applications.
• Compliance Alignment: Both components maintain ROHS3 compliance, ensuring regulatory continuity in applications subject to environmental standards.
• Active Manufacturing Status: The 701007 is currently in active production with documented inventory availability (2182 units), providing supply chain continuity for the obsolete LC502J2K.
• Mechanical Consideration: Lead length difference (38mm vs. 76mm) requires verification against PCB layout and mechanical assembly constraints; longer leads may require trimming or repositioning in existing designs.

Frequently Asked Questions (FAQ)

Q: Can the 701007 directly replace the LC502J2K without circuit modifications?

A: Electrical substitution is valid based on matching 5kΩ nominal resistance and compatible B-value thermal coefficients. Mechanical fit must be verified due to lead length difference (38mm vs. 76mm). No circuit modifications are required if mechanical accommodation is addressed.

Q: What is the significance of the B0/50 and B25/85 values?

A: The B-value defines the NTC thermistor's temperature-resistance relationship. B0/50 (3892K vs. 3891K) indicates the thermal curve between 0°C and 50°C reference points. The 701007's additional B25/85 specification (3976K) provides extended thermal characterization data not available for the LC502J2K, enabling more precise temperature calculations across wider operating ranges.

Q: Are there any compliance or certification differences?

A: Both components are ROHS3 compliant and carry identical ECCN (EAR99) and HTSUS classifications. No compliance gaps exist between the two parts.

Q: Why does the 701007 have a tighter resistance tolerance (±0.2°C vs. ±10%)?

A: The tolerance specification for the 701007 is expressed in temperature units (±0.2°C), reflecting TE Connectivity's thermal accuracy specification. The LC502J2K uses percentage-based tolerance (±10%), which is a different measurement methodology. Both specifications are valid for their respective product lines and do not prevent substitution.

Q: What should be verified before implementing the 701007 as a replacement?

A: Verify mechanical fit of the longer leads (76.20mm) within the existing PCB layout and assembly process. Confirm thermal response requirements align with the B-value specifications. Validate that the extended operating temperature range (-55°C to 150°C) does not introduce unintended behavior in applications previously limited to the LC502J2K's upper range.