KW222J2 NTC Thermistor - Equivalent & Substitute Parts

Part Overview

The KW222J2 is an NTC thermistor manufactured by Littelfuse Inc., designed as a temperature sensing component in a bead configuration with epoxy encapsulation. This part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and component procurement.

NTC (Negative Temperature Coefficient) thermistors are temperature-sensitive resistors that decrease in resistance as temperature increases. The KW222J2 serves applications requiring precise temperature measurement and thermal management across industrial and consumer electronics.

Substiute Parts

KW222J2

Littelfuse Inc.In Stock: 901KW222J2 Datasheet

Current PartRFQ

2152723205

MolexIn Stock: 23862152723205 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the KW222J2 is determined by the following critical electrical and mechanical parameters:

Electrical Equivalence Criteria:

• Resistance value at 25°C: 2.252k Ohms (tolerance ±1% or better)
• B value (B0/50): 3892K (tolerance ±1% or better)
• Operating temperature range must encompass or exceed the original specification

Mechanical Compatibility Criteria:

• Package configuration: Bead, Epoxy
• Lead wire length: Nominal 1.30" to 1.50" (33mm to 38mm)
• Mounting type: Through Hole or Free Hanging compatible

Compliance Requirements:

• RoHS3 compliance maintained
• ECCN and HTSUS classifications aligned

The substitute part 2152723205 (Molex) meets these criteria with matching electrical specifications and compatible mechanical configuration.

Parameter Comparison

Engineering Selection Recommendations

The 2152723205 (Molex) serves as a direct electrical equivalent to the KW222J2, with identical resistance and B value specifications. Both components maintain ROHS3 compliance and share the same ECCN and HTSUS classifications.

The substitute part offers an extended operating temperature range (-40°C to 135°C versus -40°C to 120°C), providing additional thermal margin for applications. The active product status of the Molex component ensures ongoing availability and supply chain continuity compared to the obsolete Littelfuse part.

Lead wire length differs by 5mm (38mm versus 33mm), requiring mechanical layout verification in applications with tight spatial constraints. Mounting type transition from free hanging to through-hole configuration may necessitate PCB footprint adjustment.

Frequently Asked Questions (FAQ)

Q: Can the 2152723205 directly replace the KW222J2 in all applications?

A: Electrical substitution is valid based on matching resistance and B value specifications. Mechanical integration requires verification of lead wire length tolerance and mounting configuration compatibility with your specific application layout.

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

A: The B value (B0/50 = 3892K) defines the thermistor's temperature-resistance characteristic curve. Matching B values ensure identical thermal response across the operating temperature range. Both parts share this specification.

Q: Does the extended temperature range of the substitute part affect compatibility?

A: The Molex part's extended range (-40°C to 135°C) is a superset of the original specification (-40°C to 120°C). This provides additional operational margin and does not compromise compatibility for applications within the original temperature window.

Q: Are there lead wire length considerations for PCB design?

A: The 5mm difference in lead wire length (38mm original versus 33mm substitute) may impact through-hole spacing and component placement. Verify hole spacing and lead routing in your PCB layout before implementation.

Q: What compliance certifications apply to both parts?

A: Both the KW222J2 and 2152723205 maintain ROHS3 compliance. The Molex part is REACH Affected, while the Littelfuse part is REACH Unaffected. Verify REACH compliance requirements for your end-use application and geographic market.