RL-1220-4-R050-FNH Equivalent & Substitute Parts

Part Overview

The RL-1220-4-R050-FNH is a 50 mOhms ±1% metal foil chip resistor in 0805 (2012 Metric) package rated for 0.5W power dissipation. Designed for current sense applications, this component is manufactured by Delta Electronics/Cyntec and is classified as obsolete. Due to its obsolete status, identifying equivalent substitute parts with matching electrical and mechanical specifications is essential for design continuity and procurement planning.

Substiute Parts

RL-1220-4-R050-FNH

Delta Electronics/CyntecIn Stock: 1171RL-1220-4-R050-FNH Datasheet

Current PartRFQ

UR732ATTD50L0F

KOA Speer Electronics, Inc.In Stock: 11890UR732ATTD50L0F Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RL-1220-4-R050-FNH is determined by the following critical parameters:

• Resistance Value: 50 mOhms (exact match required)
• Tolerance: ±1% (exact match required)
• Package: 0805 (2012 Metric) (exact match required)
• Temperature Coefficient: ±100ppm/°C (exact match required)
• RoHS Compliance: ROHS3 Compliant (required for regulatory alignment)

The substitute part UR732ATTD50L0F from KOA Speer Electronics, Inc. meets all critical electrical parameters. However, the power rating differs: the substitute is rated for 0.333W (1/3W) compared to the original 0.5W (1/2W). This represents a reduction in power handling capability and must be evaluated against circuit requirements.

Parameter Comparison

Engineering Selection Recommendations

The UR732ATTD50L0F qualifies as a functional substitute based on matching resistance, tolerance, temperature coefficient, and package specifications. Both components are ROHS3 compliant and maintain regulatory alignment.

Key considerations for selection:

• Power Dissipation: The substitute's 0.333W rating is lower than the original 0.5W. Circuit analysis must confirm that maximum power dissipation does not exceed 0.333W under worst-case operating conditions.
• Composition Difference: The original uses metal foil construction while the substitute uses thick film. This affects thermal performance and frequency response characteristics.
• Operating Temperature: The substitute's maximum operating temperature is 125°C versus the original's 170°C. Applications requiring operation above 125°C are not suitable for this substitute.
• Product Status: The substitute is active production, ensuring long-term availability and supply chain stability compared to the obsolete original.

Frequently Asked Questions (FAQ)

Q: Can UR732ATTD50L0F directly replace RL-1220-4-R050-FNH in all applications?

A: Direct replacement is possible only if circuit power dissipation does not exceed 0.333W and operating temperature remains below 125°C. The lower power rating and reduced maximum temperature are limiting factors.

Q: What is the significance of the composition difference (metal foil vs. thick film)?

A: Metal foil resistors typically offer superior frequency response and lower noise characteristics compared to thick film. Applications sensitive to high-frequency performance or noise may require evaluation of the thick film substitute's suitability.

Q: Are both components physically compatible in the same PCB footprint?

A: Both components use the 0805 (2012 Metric) package. However, the substitute has a lower seated height (0.026" vs. 0.041"), which may affect clearance in space-constrained designs but generally poses no compatibility issues.

Q: Why is the operating temperature range different?

A: The substitute's maximum operating temperature of 125°C reflects KOA Speer's design specifications for the UR73 series thick film resistor. Applications requiring operation above 125°C cannot use this substitute.

Q: Are there any compliance or certification differences?

A: Both components are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99. No compliance barriers exist for substitution from a regulatory standpoint.