Bourns 3309P-1-503 Trimmer Potentiometer - Equivalent & Substitute Parts

Part Overview

The Bourns 3309P-1-503 is a 50 kOhm, 0.5W through-hole trimmer potentiometer with PC pin termination and top adjustment. This component is classified as obsolete, making equivalent substitute parts necessary for ongoing production and maintenance applications. The 3309P series represents a legacy design in the Trimpot® product line, and active alternatives are available to maintain circuit functionality in applications requiring precision resistance adjustment.

Substiute Parts

3309P-1-503

Bourns Inc.In Stock: 7903309P-1-503 Datasheet

Current PartRFQ

91BR50KLF

TT Electronics/BIIn Stock: 104191BR50KLF Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Bourns 3309P-1-503 is determined by the following critical parameters:

• Resistance Value: 50 kOhms (exact match required)
• Power Rating: 0.5W minimum (1/2W)
• Mounting Type: Through Hole with PC Pin termination
• Adjustment Type: Top Adjustment
• Resistive Material: Cermet construction
• Number of Turns: 1-turn operation

The TT Electronics/BI 91BR50KLF meets these core functional requirements. While dimensional and tolerance specifications differ, the substitute maintains electrical compatibility for applications where the original part is no longer available. Physical size variation (0.385" x 0.375" vs. 0.453" x 0.354") must be evaluated against PCB layout constraints.

Parameter Comparison

Engineering Selection Recommendations

The TT Electronics/BI 91BR50KLF is a direct functional substitute for the obsolete Bourns 3309P-1-503. Selection is justified on the following basis:

• Product Status: The substitute is in active production, ensuring long-term availability and supply chain continuity.
• Electrical Equivalence: Resistance, power rating, adjustment type, and termination style are identical.
• Compliance: Both parts are RoHS compliant and REACH unaffected, meeting regulatory requirements.
• Performance Enhancement: The substitute offers tighter tolerance (±20% vs. ±25%) and superior temperature stability (±100ppm/°C vs. ±250ppm/°C).
• Physical Consideration: The substitute is physically smaller. PCB layout verification is required to confirm mounting compatibility.

Frequently Asked Questions (FAQ)

Q: Can the TT Electronics/BI 91BR50KLF be used as a direct replacement without circuit modification?

A: Yes, from an electrical standpoint. The substitute maintains identical resistance, power rating, and adjustment characteristics. However, physical dimensions differ; verify that the smaller footprint (9.78mm x 9.53mm vs. 11.50mm x 9.00mm) accommodates existing PCB hole patterns and mounting clearances.

Q: What is the significance of the tolerance difference between the two parts?

A: The substitute has ±20% tolerance compared to the original ±25%. This represents a tighter specification and is compatible with applications designed for the original part. No circuit redesign is necessary.

Q: How does the temperature coefficient difference affect circuit performance?

A: The substitute exhibits superior temperature stability (±100ppm/°C vs. ±250ppm/°C). This means the resistance value will drift less over temperature variations, which is beneficial for precision applications. Applications designed for the original part will experience improved performance.

Q: Is the substitute available in the same packaging as the original?

A: The original Bourns part is listed as obsolete with legacy packaging. The TT Electronics/BI substitute is available in bulk packaging and is in active production, ensuring consistent availability.

Q: Are there any compliance or certification concerns with substitution?

A: No. Both parts are RoHS compliant and REACH unaffected. Regulatory compliance is maintained with the substitute.