PW303J2 Equivalent & Substitute Parts

Part Overview

The PW303J2 is an NTC thermistor manufactured by Littelfuse Inc., featuring a 30kΩ resistance at 25°C in a bead epoxy package. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing applications and new designs. The PW303J2 serves as a temperature sensing element in thermal management and monitoring circuits where precise resistance-temperature characteristics are required.

Substiute Parts

PW303J2

Littelfuse Inc.In Stock: 1052PW303J2 Datasheet

Current PartRFQ

2152723805

MolexIn Stock: 28462152723805 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PW303J2 is determined by matching the following critical electrical and mechanical parameters:

• Resistance value at 25°C: 30kΩ
• B value (B0/50): 3892K
• Package configuration: Bead epoxy construction
• Operating temperature capability: minimum 120°C
• RoHS3 compliance status
• Lead wire dimensions and mounting compatibility

The Molex part number 2152723805 qualifies as a direct substitute based on these parameters. Both components share identical resistance and B value specifications, equivalent bead epoxy packaging, and compatible operating temperature ranges. Physical dimensions and mounting characteristics remain within acceptable tolerances for circuit board integration.

Parameter Comparison

Engineering Selection Recommendations

The Molex 2152723805 is the qualified substitute for the obsolete PW303J2. Selection is based on the following engineering criteria:

• Both components maintain identical electrical characteristics: 30kΩ resistance and 3892K B value
• ROHS3 compliance is maintained across both parts, ensuring regulatory alignment
• The Molex part features an extended operating temperature range (-40°C to 135°C) compared to the PW303J2 (up to 120°C), providing additional thermal margin
• Active product status of the Molex component ensures long-term availability and supply chain continuity
• Lead wire length differs by 5mm (38mm vs. 33mm), requiring circuit board layout verification for mechanical fit
• Mounting type transition from free hanging to through hole may require PCB design adjustment

Frequently Asked Questions (FAQ)

Q: Can the Molex 2152723805 directly replace the PW303J2 without circuit modifications?

A: Electrical substitution is direct based on matching resistance and B value specifications. However, the 5mm difference in lead wire length and the transition from free hanging to through hole mounting require mechanical verification against your specific circuit board layout and assembly process.

Q: What is the significance of the B value (3892K) in thermistor selection?

A: The B value defines the temperature-resistance relationship of the NTC thermistor. Matching B values between the original and substitute part ensures identical temperature sensing characteristics across the operating range. Both the PW303J2 and 2152723805 share the same 3892K B value.

Q: Does the resistance tolerance difference (±0.5°C vs. ±1%) affect substitution?

A: The PW303J2 specifies ±0.5°C tolerance while the Molex part specifies ±1%. This represents a wider tolerance band in the substitute. Applications requiring tighter tolerance control should evaluate whether the ±1% specification meets system accuracy requirements.

Q: Why is the operating temperature range of the Molex part wider?

A: The Molex 2152723805 operates from -40°C to 135°C, exceeding the PW303J2 specification of up to 120°C. This extended range provides additional design margin and may enable the component to function in more demanding thermal environments.

Q: Are there any compliance or certification differences between these parts?

A: Both components are ROHS3 compliant. The Molex part carries REACH Affected status while the PW303J2 is REACH Unaffected. Verify REACH compliance requirements for your specific application and end market.