KX302J2 Equivalent & Substitute Parts

Part Overview

The KX302J2 is an NTC thermistor bead manufactured by Littelfuse with a nominal resistance of 3kΩ at 25°C and a B value of 3892K. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing applications and new designs. The KX302J2 features epoxy bead packaging with free-hanging mounting and is rated for operation up to 120°C with a maximum power dissipation of 30mW.

Substiute Parts

KX302J2

LittelfuseIn Stock: 729KX302J2 Datasheet

Current PartRFQ

KW302J2

Littelfuse Inc.In Stock: 3758KW302J2 Datasheet

Parametric EquivalentRFQ

PW302J2

Littelfuse Inc.In Stock: 850PW302J2 Datasheet

Parametric EquivalentRFQ

701030

TE Connectivity Measurement SpecialtiesIn Stock: 1128701030 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the KX302J2 is determined by the following critical parameters: nominal resistance of 3kΩ at 25°C, B value in the range of 3891K to 3892K, operating temperature capability, package type (bead configuration), lead wire length, and regulatory compliance (ROHS3). Parts are grouped into two categories based on these criteria:

Parametric Equivalents (KW302J2, PW302J2): These Littelfuse parts maintain identical resistance, B value, operating temperature, power rating, lead wire length, and package configuration. They differ only in series designation and packaging format (bulk vs. tape), representing direct functional replacements with active product status.

Manufacturer Recommended Substitute (701030): This TE Connectivity part meets the core resistance and B value requirements with minor variations (B0/50 of 3891K versus 3892K, representing a 0.03% difference). It offers an extended operating temperature range (-55°C to 150°C) and improved resistance tolerance (±0.1°C). The lead wire length differs at 3.00" (76.20mm), requiring mechanical verification for application fit.

Parameter Comparison

Engineering Selection Recommendations

For direct replacement in existing designs, KW302J2 and PW302J2 are preferred substitutes. Both parts are manufactured by Littelfuse with active product status, maintain identical electrical specifications and physical dimensions, and carry ROHS3 compliance. Selection between these two depends on packaging requirements: KW302J2 is supplied in bulk packaging, while PW302J2 is also available in bulk format with current inventory of 794 pieces.

The 701030 from TE Connectivity Measurement Specialties is suitable for applications requiring extended temperature operation or improved resistance tolerance. However, the 76.20mm lead wire length (versus 38.00mm for the KX302J2) requires mechanical verification to ensure compatibility with existing PCB layouts and mechanical assemblies. All three substitute parts maintain ROHS3 compliance and EAR99 export classification.

Frequently Asked Questions (FAQ)

Q: Can KW302J2 or PW302J2 be used as direct replacements for KX302J2?

A: Yes. Both parts are parametric equivalents with identical resistance (3kΩ), B value (3892K), operating temperature (120°C), power rating (30mW), lead wire length (38.00mm), and package configuration (bead, epoxy). The primary difference is series designation and active product status.

Q: What is the significance of the B value difference between KX302J2 and 701030?

A: The B0/50 values are 3892K and 3891K respectively, representing a 0.03% difference. This minor variation falls within typical thermistor manufacturing tolerances and does not affect functional compatibility for most temperature sensing applications within the specified operating range.

Q: Does the longer lead wire of 701030 affect electrical performance?

A: Lead wire length does not affect electrical performance of the thermistor element itself. However, the 76.20mm length (versus 38.00mm) requires verification for mechanical fit in existing assemblies, PCB layouts, and mounting configurations.

Q: Are all substitute parts RoHS compliant?

A: Yes. KW302J2, PW302J2, and 701030 are all ROHS3 compliant, matching the compliance status of the KX302J2.

Q: What is the difference between the resistance tolerance specifications?

A: KX302J2 specifies ±1°C tolerance, while KW302J2 and PW302J2 specify ±0.5°C, and 701030 specifies ±0.1°C. Tighter tolerance values indicate higher manufacturing precision and may be beneficial for applications requiring more accurate resistance values at 25°C.