Brochure

P.O. Box 5928, Greenville, South Carolina 29606 U.S.A.
Tel: [phone] Fax: [phone]
POWER DISSIPATION
Power is calculated as follows:
   

  where I is the current passing through the capacitor, and ESR is the
Equivalent Series Resistance.
Power Dissipation is a term used to describe the power dissipated within the capacitor. Since ESR is
directly proportional to power, low ESR is critical to ensure the highest efficiency and stability.
CURRENT FLOW
The maximum allowable peak current flow through a capacitor is calculated as follows:
 



where V
r
is the component’s rated voltage, I is the peak current flow in amperes, and Xc is the
capacitor’s reactance.
DELTA T (ΔT)
ΔT is a term that is graphed to show the temperature rise as current increases. Capacitor manufacturers
strive for low ΔT numbers by optimizing Q and ESR, as an undesirable increase in temperature can lead to
component failure.
VOLTAGE RATING
Voltage Rating (Vr) is determined by the inherent dielectric strength (and associated breakdown voltage –
DWV) of the dielectric material. In all dielectric classes, MLCC manufacturers strive to achieve the highest
capacitance, the highest rated voltage, in the most reliable, smallest package (and at a market competitive
price). This is true for RF capacitors as well.
DWV
Dielectric Withstanding Voltage, DWV, can be expressed as capability in volts/mil of dielectric thickness.
Due to the material set and manufacturing techniques, RF capacitors have inherently higher volts/mil
capability than standard Class 1 and Class 2 capacitors.
Voltage breakdown can occur either inside the capacitor, or outside (across the two terminals). Voltage
breakdown typically is a higher risk in higher V
r
devices, typically above 3kV. This external voltage
breakdown is sometimes called “flashover”.