Vishay Cera-Mite 440LD39-R Equivalent & Substitute Parts

Part Overview

The Vishay Cera-Mite 440LD39-R is a 3900 pF ceramic capacitor rated for 760VAC with Y5U temperature coefficient, designed for safety-critical applications requiring X1 and Y1 ratings. This component is currently active in production with full inventory availability. Substitute parts may be required due to lead time constraints, regional availability, or specific packaging requirements while maintaining electrical and mechanical compatibility within defined parameters.

Substiute Parts

440LD39-R

Vishay Cera-MiteIn Stock: 913440LD39-R Datasheet

Current PartRFQ

C961U392MVWDBA7317

KEMETIn Stock: 774C961U392MVWDBA7317 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 440LD39-R is determined by the following critical parameters:

• Capacitance Value: Must be 3900 pF ±20%
• Temperature Coefficient: Must be Y5U (E)
• Safety Ratings: Must include X1 and Y1 certifications
• Mounting Configuration: Must be Through Hole with Radial, Disc package
• Voltage Rating: Substitute must meet or exceed 760VAC requirement
• Compliance: Must maintain ROHS3 and REACH Unaffected status

The KEMET C961U392MVWDBA7317 qualifies as a substitute based on matching capacitance, tolerance, temperature coefficient, safety ratings, and mounting type. However, the voltage rating of 400VAC is lower than the main part's 760VAC specification and must be evaluated for application requirements.

Parameter Comparison

Engineering Selection Recommendations

Both components maintain ROHS3 compliance and REACH Unaffected status, meeting regulatory requirements for safety-critical applications. The primary distinction is the voltage rating differential: the main part is rated for 760VAC while the substitute is rated for 400VAC. Selection between these parts must be based on the actual voltage requirement of the application circuit. The KEMET substitute provides an extended lower operating temperature limit (-40°C versus -30°C), which may be advantageous in certain thermal environments. Packaging format differs between bulk and cut tape configurations, affecting procurement and assembly workflows.

Frequently Asked Questions (FAQ)

Q: Can the KEMET C961U392MVWDBA7317 be used in place of the Vishay 440LD39-R in all applications?

A: Substitution is valid only when the application voltage requirement does not exceed 400VAC. The 440LD39-R's 760VAC rating provides higher voltage margin. If the circuit operates at voltages between 400VAC and 760VAC, the substitute is not suitable.

Q: Are the physical dimensions compatible between these parts?

A: Both components use Radial, Disc package configuration with Through Hole mounting. The Vishay part has a 0.531" diameter (14.60mm) with 0.374" lead spacing (9.50mm), while the KEMET part has a 0.512" diameter (13.00mm) with 0.394" lead spacing (10.00mm). These dimensional differences are minor and typically accommodate standard PCB footprints designed for radial ceramic capacitors.

Q: What is the significance of the Y5U temperature coefficient?

A: Y5U indicates the capacitor exhibits a capacitance change of -82% to +22% across the operating temperature range of -30°C to +85°C (or -40°C to +125°C for extended range). This specification is critical for safety applications and must be maintained in any substitute.

Q: Do both parts carry the same safety certifications?

A: Yes, both the Vishay 440LD39-R and KEMET C961U392MVWDBA7317 carry X1 and Y1 safety ratings, indicating suitability for line-to-neutral and line-to-ground applications respectively.

Q: What is the difference between Bulk and Cut Tape packaging?

A: Bulk packaging is supplied as loose components, while Cut Tape (CT) packaging provides components on adhesive tape in specified quantities. Cut Tape is typically preferred for automated assembly processes, while Bulk may be more economical for manual assembly or lower-volume applications.