SAL electrolytic capacitor
SAL electrolytic capacitor ( SAL = English s olid al uminium ) is a manufacturer's name for aluminum electrolytic capacitors with the solid electrolyte manganese dioxide , also known as " manganese dioxide ". They consist of etched and shaped folded aluminum anodes into which the electrolyte is introduced and solidified with the help of a pyrolytic process. SAL electrolytic capacitors were offered in pearl-shaped and axial designs until the end of 2015.
General
The solid electrolyte, which cannot dry out in comparison to a liquid electrolyte, offers a very high long-term stability of the characteristic values without significant changes and a very low dependence of the impedance and the ESR on the temperature. The capacitors are switch-proof and can be operated without a series resistor, which makes the SAL electrolytic capacitors stand out from the tantalum electrolytic capacitors . In addition, the dielectric aluminum dioxide in combination with the electrolyte manganese dioxide has a relatively high reverse polarity voltage resistance.
SAL electrolytic capacitors were developed by Philips in the 1960s and had success in the 1980s as a replacement for tantalum electrolytic capacitors with solid manganese dioxide electrolytes. With the advent of SMD technology , these SAL capacitors lost their importance, as they were unsuccessful in the SMD design. Production of this type was discontinued at the end of 2015 by the only remaining manufacturer, Vishay .
standardization
The conditions for the tests and measurements of the electrical parameters of aluminum electrolytic capacitors with liquid electrolytes are specified in the basic specification:
as well as in the frame specifications:
- IEC 60384-4, aluminum electrolytic capacitors with solid (manganese dioxide) or liquid electrolytes
- IEC 60384-18, surface mount aluminum electrolytic capacitors with solid (manganese dioxide) or liquid electrolyte
In Germany these standards are published as part of the DIN EN 60384 series of standards .
Applications
- Buffer and filter capacitor in low-drop converters in automotive electronics
- Secondary filter capacitor in miniaturized SMPS-AC-DC converters
Advantages and disadvantages
Advantages compared to aluminum electrolytic capacitors with liquid electrolytes:
- significantly higher ripple current capacity
- better low temperature behavior. The impedance and the ESR are only about twice higher at −40 ° C than at room temperature
- axial design temperature resistant up to 200 ° C
- stable characteristic values, no service life limited by evaporation.
- relatively high resistance to reverse polarity.
Disadvantages compared to aluminum electrolytic capacitors with liquid electrolytes:
- They are more expensive than "wet Al-Elkos".
- only one manufacturer