LR502F0J NTC Thermistor Equivalent & Substitute Parts

Part Overview

The LR502F0J is an NTC thermistor manufactured by Littelfuse Inc., designed for temperature sensing applications requiring a 5kΩ resistance at 25°C with a B25/85 value of 3550K. The component is packaged in a 1206 (3216 Metric) surface mount format with an operating temperature range of -40°C to 125°C and maximum power dissipation of 400 mW.

The LR502F0J is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for systems utilizing this thermistor.

Substiute Parts

LR502F0J

Littelfuse Inc.In Stock: 1119LR502F0J Datasheet

Current PartRFQ

NHQ502B355T5

Amphenol ThermometricsIn Stock: 879NHQ502B355T5 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LR502F0J are identified based on strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

• Resistance value at 25°C: 5kΩ (exact match required)
• Resistance tolerance: ±5% (matching tolerance band)
• B25/85 thermal coefficient: 3550K (exact match required)
• Operating temperature range: -40°C to 125°C (minimum coverage required)
• Package / Case: 1206 (3216 Metric) (mechanical compatibility)
• Mounting type: Surface Mount (assembly compatibility)
• Moisture Sensitivity Level: 1 (Unlimited) (environmental compatibility)

The NHQ502B355T5 from Amphenol Thermometrics meets all primary substitution criteria and is classified as an active product, providing supply continuity for the obsolete LR502F0J.

Parameter Comparison

Engineering Selection Recommendations

The NHQ502B355T5 is a direct functional equivalent to the LR502F0J based on matching electrical characteristics (5kΩ resistance, ±5% tolerance, 3550K B25/85 value) and mechanical compatibility (1206 package, surface mount, MSL 1).

Product Status Consideration: The NHQ502B355T5 is classified as active, ensuring ongoing availability and supply chain support compared to the obsolete LR502F0J.

Compliance Consideration: The LR502F0J is ROHS3 compliant, while the NHQ502B355T5 is RoHS non-compliant. Design teams must evaluate regulatory requirements for their specific application and market region before substitution.

Both parts share identical ECCN (EAR99) and HTSUS (8533.40.8070) classifications, indicating equivalent export and tariff treatment.

Frequently Asked Questions (FAQ)

Q: Can the NHQ502B355T5 be used as a direct replacement for the LR502F0J?

A: Yes, the NHQ502B355T5 meets all primary electrical and mechanical substitution criteria: identical 5kΩ resistance at 25°C, ±5% tolerance, 3550K B25/85 value, -40°C to 125°C operating range, and 1206 (3216 Metric) surface mount package. However, RoHS compliance status differs and must be evaluated against application requirements.

Q: What is the significance of the B25/85 value in thermistor selection?

A: The B25/85 value (3550K) defines the thermal sensitivity of the NTC thermistor between 25°C and 85°C. This parameter must match exactly for equivalent temperature sensing performance. Both the LR502F0J and NHQ502B355T5 share this specification.

Q: Are there packaging differences between these parts?

A: Both parts use identical 1206 (3216 Metric) surface mount packaging. The LR502F0J is supplied in standard packaging, while the NHQ502B355T5 is supplied in Tape & Reel (TR) format. This difference affects handling and assembly processes but does not impact electrical or mechanical compatibility.

Q: What should be considered regarding RoHS compliance?

A: The LR502F0J is ROHS3 compliant, while the NHQ502B355T5 is RoHS non-compliant. Applications subject to RoHS regulations (primarily EU markets) must verify that substitution with a non-compliant part meets applicable legal and contractual requirements.

Q: Is the maximum power dissipation specification critical for substitution?

A: The LR502F0J specifies 400 mW maximum power dissipation. The NHQ502B355T5 does not provide this specification in available documentation. Design teams should confirm that the NHQ502B355T5 meets or exceeds the 400 mW requirement for their specific application before implementation.