Mica and PTFE Capacitors

Part Number	Description / PDF	Quantity
CP-SM-150-500V TubeDepot	SILVER MICA 150PF / 500V	116
CP-SM-390-500V TubeDepot	SILVER MICA 390PF / 500V	352
CP-SM-220-500V TubeDepot	SILVER MICA 220PF / 500V	0
CP-SM-1000-500V TubeDepot	SILVER MICA 1000PF / 500V	90
CP-SM-68-500V TubeDepot	SILVER MICA 68PF / 500V	147
CP-SM-47-500V TubeDepot	SILVER MICA 47PF / 500V	102
CP-SM-22-500V TubeDepot	SILVER MICA 22PF / 500V	332
CP-SM-120-500V TubeDepot	SILVER MICA 120PF / 500V	67
CP-SM-250-500V TubeDepot	SILVER MICA 250PF / 500V	78
CP-SM-100-500V TubeDepot	SILVER MICA 100PF / 500V	0
CP-SM-33-500V TubeDepot	SILVER MICA 33PF / 500V	112
CP-SM-680-500V TubeDepot	SILVER MICA 680PF / 500V	154
CP-SM-10-500V TubeDepot	SILVER MICA 10PF / 500V	850
CP-SM-500-500V TubeDepot	SILVER MICA 500PF / 500V	420

Mica and PTFE Capacitors

1. Overview

Mica and PTFE (Polytetrafluoroethylene) capacitors are specialized electronic components utilizing mica or PTFE as dielectric materials. Known for exceptional stability, low loss, and high-temperature resistance, they are critical in precision and high-frequency applications. Mica capacitors leverage natural mineral sheets for superior electrical properties, while PTFE capacitors offer excellent chemical resistance and thermal stability up to 200 C.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Mica Capacitors	High Q factor, low leakage current, stable over temperature/humidity	RF tuning circuits, military-grade oscillators
PTFE Film Capacitors	Self-healing properties, high dielectric strength, low moisture absorption	High-frequency power supplies, medical imaging equipment
High-Voltage PTFE Capacitors	Rated >1kV, arc-resistant design	Laser power systems, aerospace ignition modules

3. Structure and Composition

Mica Capacitors: Constructed by sandwiching mica sheets between vacuum-deposited aluminum electrodes. Encapsulated in ceramic or plastic shells with epoxy sealing. PTFE Capacitors: Made by winding PTFE film with metallized electrodes or using stacked foil structures. Terminations use silver epoxy or welded leads for low resistance.

4. Key Technical Specifications

Parameter	Typical Values	Importance
Capacitance Range	1pF-10 F (Mica), 100pF-4.7 F (PTFE)	Determines frequency response and filtering capability
Voltage Rating	50V-10kV	Defines operational safety margin
Temperature Coefficient	5-100ppm/ C	Stability in varying thermal conditions
Dissipation Factor	0.0001-0.002	Energy loss efficiency
Operating Temperature	-55 C to +200 C	Environmental durability

5. Application Areas

Key industries: Telecommunications (RF amplifiers), Aerospace (avionics filters), Medical (MRI gradient coils), Industrial (precision test equipment). Example: 1000V-rated PTFE capacitors in MRI machine deflection coil drivers.

6. Leading Manufacturers and Products

Manufacturer	Product Series	Key Specifications
Murata Manufacturing	NME3 Series	0.1-10nF, 500V, 30ppm/ C
KEMET	C8AK Series	100pF-4.7nF, 1kV, -55 C to +150 C
Vishay Beyschlag	MKP385 Series	1nF-1 F, self-healing, 200 C rating

7. Selection Guidelines

Consider: 1) Required capacitance tolerance (< 1% for critical filters), 2) Voltage derating (use 80% of rating), 3) Temperature extremes (select >20% margin), 4) Mechanical stress (radial vs axial leads), 5) Cost vs lifetime (mica preferred for >10 year deployments).

8. Industry Trends

Emerging trends: Miniaturization for 5G mmWave circuits, hybrid mica-PTFE composites for improved thermal management, and increased adoption in EV charging systems (1500V PTFE capacitors). Market growth projected at 7.2% CAGR (2023-2030) per Grand View Research.