Knowles Voltronics P3F Trimmer Capacitor: Equivalent & Substitute Parts

Part Overview

The Knowles Voltronics P3F is a 0.6–2.5 pF trimmer capacitor rated for 500 V operation with top-side adjustment and sapphire dielectric construction. Designed for surface mount applications, this component features non-magnetic construction and operates across the temperature range of −65°C to 125°C. The P3F is classified as obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations where equivalent performance is required.

Key Parameters

Parameter	Value
Manufacturer Part Number	P3F
Manufacturer	Knowles Voltronics
Capacitance Range	0.6–2.5 pF
Voltage Rating	500 V
Dielectric Material	Sapphire
Adjustment Type	Top
Mounting Type	Surface Mount
Size / Dimension	0.140" Dia (4.66 mm)
Height – Seated (Max)	0.240" (6.10 mm)
Operating Temperature Range	−65°C to 125°C
Q @ Frequency	4000 @ 250 MHz
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the P3F is determined by strict alignment of the following electrical and mechanical parameters:

Capacitance Range Overlap: The substitute must cover or encompass the required 0.6–2.5 pF range. A substitute with a lower minimum (e.g., 0.4 pF) remains compatible provided the upper limit meets or exceeds 2.5 pF.
Voltage Rating: Must equal or exceed 500 V to ensure safe operation under rated conditions.
Dielectric Material: Sapphire dielectric is required to maintain electrical performance characteristics.
Adjustment Type: Top adjustment is mandatory for mechanical compatibility with existing tuning mechanisms.
Mounting Type: Surface mount construction is required for PCB integration.
Physical Dimensions: The footprint (0.140" diameter) and height must be compatible with existing board layouts. Minor height variations (within manufacturing tolerance) are acceptable if the component fits within the allocated space.
Operating Temperature Range: Must support −65°C to 125°C operation.
Q Factor: 4000 @ 250 MHz establishes the baseline for RF performance; substitutes meeting this specification ensure equivalent signal integrity.

The Knowles Johanson Manufacturing 27283 (Giga-Trim® series) satisfies all substitution criteria and is classified as an active product, providing long-term availability and supply chain continuity.

Parameter Comparison

Parameter	P3F (Knowles Voltronics)	27283 (Knowles Johanson)	Compatibility
Capacitance Range	0.6–2.5 pF	0.4–2.5 pF	Compatible (27283 range encompasses P3F range)
Voltage Rating	500 V	500 V	Equivalent
Dielectric Material	Sapphire	Sapphire	Equivalent
Adjustment Type	Top	Top	Equivalent
Mounting Type	Surface Mount	Surface Mount	Equivalent
Size / Dimension	0.140" Dia (4.66 mm)	0.140" Dia (4.66 mm)	Equivalent
Height – Seated (Max)	0.240" (6.10 mm)	0.225" (5.72 mm)	Compatible (27283 is lower profile)
Operating Temperature Range	−65°C to 125°C	−65°C to 125°C	Equivalent
Q @ Frequency	4000 @ 250 MHz	4000 @ 250 MHz	Equivalent
Product Status	Obsolete	Active	27283 provides ongoing availability

Engineering Selection Recommendations

The Knowles Johanson Manufacturing 27283 is the qualified substitute for the obsolete P3F. Selection is based on the following engineering criteria:

Electrical Equivalence: Both components maintain identical voltage rating, dielectric material, Q factor, and operating temperature range. The 27283 capacitance range (0.4–2.5 pF) fully encompasses the P3F specification (0.6–2.5 pF), ensuring functional compatibility across all tuning requirements.
Mechanical Compatibility: Identical footprint diameter (0.140" / 4.66 mm) and adjustment mechanism (top) ensure direct PCB integration without layout modification. The 27283 exhibits a lower seated height (0.225" vs. 0.240"), which provides additional clearance margin in space-constrained applications.
Product Status and Supply Chain: The 27283 is classified as active with RoHS3 compliance certification, ensuring long-term availability and regulatory alignment for new designs and production support.
Functional Continuity: Direct substitution of the 27283 for the P3F maintains system performance without circuit redesign or tuning algorithm modification.

Frequently Asked Questions (FAQ)

Q: Can the 27283 be used as a direct replacement for the P3F in existing designs?

A: Yes. The 27283 is electrically and mechanically equivalent to the P3F. Identical adjustment type, voltage rating, dielectric material, and Q factor ensure functional continuity. The lower profile height of the 27283 (0.225" vs. 0.240") provides additional board clearance without affecting performance.

Q: What is the significance of the capacitance range difference (0.4–2.5 pF vs. 0.6–2.5 pF)?

A: The 27283 offers an extended lower capacitance limit (0.4 pF vs. 0.6 pF). This provides additional tuning range flexibility. For applications requiring only the 0.6–2.5 pF range, the 27283 remains fully compatible and can be tuned to any value within the original P3F specification.

Q: Are there any compliance or certification differences between the P3F and 27283?

A: The 27283 carries RoHS3 compliance certification, whereas the P3F compliance status is not specified in the provided data. For new designs and regulated applications, the 27283 is the recommended choice due to its active product status and documented compliance.

Q: Does the lower height of the 27283 affect PCB layout or assembly?

A: No. The 0.225" seated height of the 27283 is lower than the P3F specification (0.240"), providing additional clearance. This is advantageous in space-constrained designs and does not introduce compatibility issues.

Q: Is the 27283 available in the same packaging as the P3F?

A: The 27283 is supplied in bulk packaging. Verify packaging requirements with your procurement specification to ensure alignment with assembly and inventory management processes.

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