KT222J2 NTC Thermistor - Equivalent & Substitute Parts

Part Overview

The KT222J2 is an NTC thermistor manufactured by Littelfuse, classified as a temperature sensor in bead form with epoxy encapsulation. This component features a resistance of 2.252kΩ at 25°C and a B-value of 3892K, designed for thermal sensing applications requiring free-hanging mounting. The product is currently obsolete, making identification of compatible substitute parts essential for ongoing system support and component procurement.

Substiute Parts

KT222J2

LittelfuseIn Stock: 1064KT222J2 Datasheet

Current PartRFQ

2152723205

MolexIn Stock: 23862152723205 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KT222J2 is determined by the following critical electrical and mechanical parameters:

• Resistance Value: 2.252kΩ at 25°C (primary thermal characteristic)
• B-Value: 3892K (defines temperature response curve)
• Package Type: Bead form with epoxy encapsulation
• Operating Temperature Range: Maximum 135°C
• Power Dissipation: 30 mW maximum
• Lead Wire Configuration: Physical dimensions and mounting compatibility

The Molex part number 2152723205 qualifies as a substitute based on matching resistance value, B-value, package form, and operating temperature specifications. Both components are ROHS3 compliant and share identical HTSUS classification, confirming regulatory and material compatibility.

Parameter Comparison

Engineering Selection Recommendations

The Molex 2152723205 is the qualified substitute for the obsolete KT222J2. Both components meet ROHS3 compliance requirements and share identical HTSUS classification, confirming material and regulatory compatibility for procurement and deployment.

The Molex part offers extended operating temperature range (-40°C to 135°C versus 135°C maximum for the original), providing broader thermal coverage. Lead wire length differs by 5mm (33mm versus 38mm), requiring mechanical fit verification in the target application. Resistance tolerance specification differs (±1% versus ±0.2°C), which may impact thermal measurement precision depending on system calibration requirements.

Product status transition from obsolete to active ensures long-term availability and supply chain continuity for the Molex alternative.

Frequently Asked Questions (FAQ)

Q: Can the Molex 2152723205 directly replace the KT222J2 without circuit modification?

A: Electrical substitution is valid based on matching resistance value (2.252kΩ) and B-value (3892K). Mechanical fit requires verification due to 5mm lead wire length difference and mounting type variation (through hole versus free hanging).

Q: What is the significance of the B-value match between these components?

A: The B-value (3892K) defines the temperature response curve of the NTC thermistor. Matching B-values ensure identical thermal sensing characteristics across the operating temperature range, critical for accurate temperature measurement.

Q: Does the resistance tolerance difference affect substitution suitability?

A: The KT222J2 specifies ±0.2°C tolerance while the Molex part specifies ±1% tolerance. This difference may impact thermal measurement accuracy in precision applications. System calibration requirements should be evaluated.

Q: Are there compliance or regulatory concerns with this substitution?

A: Both components are ROHS3 compliant and share identical HTSUS classification (8533.40.8070), confirming regulatory and material compatibility. The Molex part is REACH Affected while the original is REACH Unaffected; procurement and supply chain documentation should reflect this distinction.

Q: Why is the operating temperature range wider for the substitute part?

A: The Molex 2152723205 specifies -40°C to 135°C, extending the lower temperature limit compared to the KT222J2 specification of 135°C maximum. This provides additional thermal coverage for applications requiring sub-zero operation.