DC301F3K NTC Thermistor 300Ω Temperature Sensor Equivalent & Substitute Parts

Part Overview

The DC301F3K is an NTC thermistor manufactured by Littelfuse, designed for temperature sensing applications requiring a 300Ω resistance at 25°C with a B0/50 value of 3419K. This component features a bead configuration with epoxy packaging and operates across a temperature range of -55°C to 150°C. The part is classified as obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

DC301F3K

LittelfuseIn Stock: 1112DC301F3K Datasheet

Current PartRFQ

RL2008-187-73-D1

Amphenol ThermometricsIn Stock: 3881RL2008-187-73-D1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for NTC thermistor sensors is determined by the following critical parameters:

Primary Matching Criteria:

• Resistance value at 25°C: 300Ω (exact match required)
• Resistance tolerance: ±10% (must be equivalent or tighter)
• B-value characteristics: Thermal response curve must be compatible with application requirements
• Operating temperature range: Must encompass or match the original specification (-55°C to 150°C minimum)
• RoHS and compliance status: Must maintain regulatory compliance (ROHS3 Compliant, EAR99, HTSUS 8533.40.8070)

Secondary Considerations:

• Package configuration (bead vs. disc) affects thermal response and mounting compatibility
• Lead wire length and mounting type influence circuit integration
• Moisture sensitivity level (MSL 1) indicates no moisture-related restrictions

The RL2008-187-73-D1 qualifies as a substitute based on matching the 300Ω resistance specification, ±10% tolerance, compatible operating temperature range (-50°C to 150°C), and equivalent compliance certifications. The B25/85 value of 3468K provides thermal response characteristics suitable for temperature sensing applications within the specified operating window.

Parameter Comparison

Engineering Selection Recommendations

The RL2008-187-73-D1 is the designated manufacturer-recommended substitute for the obsolete DC301F3K. Both components maintain ROHS3 compliance and carry identical moisture sensitivity ratings, ensuring regulatory and environmental consistency.

Selection Basis:

The substitute maintains the critical 300Ω resistance specification and ±10% tolerance required for thermal sensing accuracy. The operating temperature range of -50°C to 150°C covers the upper and lower bounds of the original specification, with the lower limit reduced by 5°C. This difference is acceptable for most applications unless the design specifically requires operation below -50°C.

The primary physical difference is the package configuration: the RL2008-187-73-D1 uses a disc form factor (5.6mm diameter × 4.3mm width) with through-hole mounting, compared to the bead configuration with free-hanging leads in the original part. This change may require circuit board layout modifications and thermal interface adjustments, as disc packages typically offer different thermal coupling characteristics than bead designs.

The extended lead wire length (1.50" vs. 1.00") provides additional routing flexibility in circuit integration. Both components are classified as MSL 1, indicating no moisture-related handling restrictions during storage or assembly.

Frequently Asked Questions (FAQ)

Q: Can the RL2008-187-73-D1 be used as a direct drop-in replacement for the DC301F3K?

A: The RL2008-187-73-D1 matches the electrical specifications (300Ω, ±10% tolerance) and operating temperature range, making it functionally equivalent. However, the physical package differs: the original uses a bead configuration with free-hanging leads, while the substitute uses a disc package with through-hole mounting. Circuit board layout and thermal interface design may require modification to accommodate the different form factor.

Q: What is the significance of the B-value difference between the two parts?

A: The DC301F3K specifies B0/50 = 3419K, while the RL2008-187-73-D1 specifies B25/85 = 3468K. Both values characterize the thermal response curve of the NTC thermistor. The slight difference (49K) reflects different measurement reference points and is within acceptable variation for temperature sensing applications. The substitute's B-value ensures compatible thermal response within the specified operating range.

Q: Does the lower minimum operating temperature of the RL2008-187-73-D1 (-50°C vs. -55°C) affect compatibility?

A: The substitute's minimum operating temperature is -50°C, compared to -55°C for the original. If your application requires operation below -50°C, the substitute is not suitable. For applications operating at -50°C or above, this difference is not a limiting factor.

Q: Are there any compliance or regulatory differences between the two parts?

A: Both components are ROHS3 compliant, carry EAR99 ECCN classification, and share the same HTSUS code (8533.40.8070). Moisture sensitivity levels are identical (MSL 1, Unlimited). No compliance or regulatory differences exist between the parts.

Q: How does the package change from bead to disc affect thermal response?

A: Disc packages typically provide different thermal mass and surface area characteristics compared to bead configurations. The disc form factor (5.6mm diameter × 4.3mm width) may result in different thermal time constants and coupling efficiency depending on the mounting interface. Thermal performance validation is recommended if the application has strict thermal response requirements.

Q: Is the longer lead wire length (1.50" vs. 1.00") a concern?

A: The extended lead wire provides additional routing flexibility and may reduce mechanical stress on solder joints in some circuit configurations. This is generally beneficial and does not introduce compatibility issues. The longer leads may require adjustment of circuit board layout and component placement.