Like all capacitors, the key function of Electrolytic Capacitors, also known as E-Caps or Lytics, is to act as a physical store for voltage charge. Conventional electrolytic capacitors are constructed of two metal foil electrodes, one of which has an oxidized surface, that are separated by electrolyte soaked paper and rolled into a tubular form.
E-Caps first appeared on the market in 1978 as Farad-sized devices and have been used since then for any electronic device to support AC/DC and DC/DC conversion providing voltage hold-up. There was some doubt about the continued use of capacitors due to the development of IC and VLSI devices. These doubts have proven to be unfounded and E-Cap production has risen steadily. In the beginning, electrolytic capacitors were used primarily in electrical and electronic products but today they are used in fields ranging from industrial applications to automotive, aircraft and space, medicine, computers, games, power supply circuits and other power electronics.
Common market segments using Electrolytic Capacitors:
- Power Supplies: linear and switched mode, voltage regulators and converters (DC-DC/AC-DC)
- Telecommunications/Networking Equipment: frequency elements involved, decoupling requirements
- Audio/Video Equipment: for noise filtering
- Consumer Appliance: power and control systems
- Automotive: electronic control, display systems and ADAS
- Medical: monitoring equipment, electro surgery
- Industrial Usage: control systems, motor start/stop applications, data acquisition
- Lighting Requirements: LED driver applications
Consumed in many of the key end products that drive the global high-technology economy they are used for bypass, decoupling, filtering and burst power on consumer, professional and mission critical circuits. Electrolytic capacitors are used widely in applications which demand a large capacity whilst requiring small case size and low price. This combination of large capacity and small size has led to dominance, and E-caps now represent the majority of the market within the field of capacitors. Customers can take advantage of key characteristics:
- Large Capacity
- High Temperature
- Low ESR
- High Endurance
- High Ripple Current Handling
- Low Cost
Electrolytic Capacitors are predominantly separated into SMD and Radial/THT types. Currently, Radial E-caps dominate with almost 55% of the market share, whilst SMD E-caps have been the fastest growing segment for the last 15 years due to smaller footprint, ease of soldering, increasing CV and smaller case size. The decision to use either SMD or Radial E-caps is usually driven by the varying requirements of ripple current, operating and reflow temperatures, ESR characteristics and cost.
Radial/THT Electrolytic Capacitors
Specifically designed for demanding applications that require very long life and high ripple current, some of the range are also automotive qualified (AEC-Q200 qualified) and are particularly used in powertrain systems. Operating temperatures up to 150°C are available without voltage derating, and lifespan ranges from 2000 hours to 10000 hours dependent on application needs and operating temperature.
Example applications include:
- Automotive: infotainment and air bags
- Industrial power distribution / LED lighting solutions
- Telecom infrastructure
- DC/DC converters
- Motor start/stop systems
SMD Electrolytic Capacitors
Popular in automotive applications, especially for mission critical application such as ADAS, SMD E-Caps are ideal for designs requiring long life, high ripple current, high reliability and low ESR. They are available in anti-vibration variants, designed to withstand up to 30G, and have an operating temperature range of between -55°C and 150°C. As with radial E-caps, lifespan ranges between 2000 hours and 10000 hours, dependent on application needs and operating temperature.
Typical applications include:
- GPUs and Video Accelerators
- Digital Flatscreen and Panels
- DC/DC Converters
- Motor Control
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