RB204R0J NTC Thermistor 200kΩ 0603 Equivalent & Substitute Parts

Part Overview

The RB204R0J is an NTC thermistor manufactured by Littelfuse Inc., designed for temperature sensing applications requiring a 200kΩ resistance at 25°C with a B25/85 value of 4250K. This component is packaged in 0603 (1608 Metric) surface mount format and operates across the temperature range of -40°C to 125°C.

The RB204R0J is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or repair requirements for systems utilizing this thermistor.

Key Parameters

Parameter	Value	Significance for Substitution
Resistance @ 25°C	200kΩ	Primary electrical specification; must match exactly
Resistance Tolerance	±5%	Defines acceptable resistance variation; critical for circuit accuracy
B25/85 Value	4250K	Determines temperature coefficient; must match for thermal response equivalence
Operating Temperature Range	-40°C to 125°C	Defines functional temperature limits; substitute must meet or exceed this range
Package / Case	0603 (1608 Metric)	Physical footprint; must match for PCB compatibility
Mounting Type	Surface Mount	Assembly method; must be compatible with existing manufacturing process
Power - Max	150 mW	Maximum dissipation rating; substitute must support this power level
Moisture Sensitivity Level (MSL)	1 (Unlimited)	Storage and handling requirements; lower MSL indicates less stringent conditions

Substitute Part Grouping Explanation

Substitute parts for the RB204R0J are identified based on strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

Resistance value at 25°C: 200kΩ (exact match required)
Resistance tolerance: ±5% (matching tolerance band)
B25/85 thermal coefficient: 4250K (exact match required for thermal response)
Operating temperature range: -40°C to 125°C (minimum requirement)
Package / Case: 0603 (1608 Metric) (physical compatibility)
Mounting type: Surface Mount (assembly compatibility)

The NHQMM204B425T5 from Amphenol Thermometrics meets all substitution criteria. This part maintains identical electrical specifications (200kΩ ±5%, B25/85 = 4250K) and physical form factor, ensuring functional equivalence in circuit applications.

Parameter Comparison

Parameter	RB204R0J (Littelfuse)	NHQMM204B425T5 (Amphenol Thermometrics)	Match Status
Resistance @ 25°C	200kΩ	200kΩ	Exact Match
Resistance Tolerance	±5%	±5%	Exact Match
B25/85 Value	4250K	4250K	Exact Match
Operating Temperature Range	-40°C to 125°C	-40°C to 125°C	Exact Match
Package / Case	0603 (1608 Metric)	0603 (1608 Metric)	Exact Match
Mounting Type	Surface Mount	Surface Mount	Exact Match
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Exact Match
RoHS Status	ROHS3 Compliant	RoHS Compliant	Compatible
ECCN Classification	EAR99	EAR99	Exact Match
HTSUS Code	8533.40.8070	8533.40.8070	Exact Match

Engineering Selection Recommendations

The NHQMM204B425T5 is a direct functional equivalent to the RB204R0J. Selection between these parts should be based on the following factors:

Product Status: The RB204R0J is obsolete, while the NHQMM204B425T5 is active. For new designs or ongoing production, the NHQMM204B425T5 is the recommended choice to ensure long-term supply availability.

Compliance & Certifications: Both parts meet RoHS requirements and share identical ECCN and HTSUS classifications, ensuring regulatory and export compliance equivalence.

Packaging: The RB204R0J is supplied in standard packaging, while the NHQMM204B425T5 is available in Tape & Reel (TR) format. Tape & Reel packaging is standard for high-volume surface mount assembly and offers improved handling efficiency.

Inventory & Availability: Current stock levels indicate both parts are available. The NHQMM204B425T5 should be prioritized for new procurement due to its active product status.

Frequently Asked Questions (FAQ)

Q: Can the NHQMM204B425T5 be used as a direct replacement for the RB204R0J in existing designs?

A: Yes. The NHQMM204B425T5 matches all critical electrical parameters (200kΩ ±5% at 25°C, B25/85 = 4250K) and physical specifications (0603 package, surface mount). No circuit modifications are required.

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

A: The B25/85 value (4250K) defines the thermistor's temperature coefficient and determines its resistance change across the operating temperature range. Matching this value ensures identical thermal response characteristics between the original and substitute part.

Q: Are there any differences in handling or storage between these two parts?

A: Both parts have MSL 1 (Unlimited) rating, indicating identical moisture sensitivity and storage requirements. No special handling differences apply.

Q: Why is the package format (0603) critical for substitution?

A: The 0603 (1608 Metric) package defines the physical footprint and pin spacing. Using a substitute with a different package would require PCB redesign and assembly process changes, making it incompatible with existing designs.

Q: Does the Tape & Reel packaging of the NHQMM204B425T5 affect its electrical performance?

A: No. Tape & Reel is a packaging and delivery format only. It does not affect the electrical characteristics or performance of the thermistor itself. It is standard for surface mount component assembly.

Q: Are both parts compliant with current environmental regulations?

A: Yes. Both the RB204R0J and NHQMM204B425T5 are RoHS compliant and share identical ECCN (EAR99) and HTSUS (8533.40.8070) classifications, ensuring regulatory equivalence.

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