Micro-ceramic chip capacitor for printed circuit board (PCB) surface mounting, there are two types, single layer capacitor (SLC) and multi-layer chip capacitor (MLCC). They are commonly used in radio-frequency circuit, microwave circuit due to their small size. So the question is, how to choose between these two types of chip capacitor for customers? What's the difference between them?
Capacitance range of single layer capacitor is from 0.05pF to 10000pF, DC rated operating voltages can reach 100V, operating frequency of single layer capacitor can up to 100GHz. The capacitance range of multi-layer chip capacitor is wider than that of single layer capacitor, and its DC rated operating voltage can be as high as 7200V, which is mainly used in high-frequency electrical signals below 3GHz.
Compared with multi-layer capacitor, single layer capacitor has lower series equivalent resistance, higher quality factor and higher reliability, which can better meet the demanding requirements of microwave and millimeter-wave frequency electronic circuits. It can be widely applied on microwave integrated circuit (MIC) and microwave monolithic integrated circuit (MMIC), such as, amplifier, oscillator and mixer, etc. It can realize the functions of DC blocking, RF bypass, active bypass, smoothing, impedance matching and coplanar waveguide.
There are three common medium types for single layer capacitor and multi-layer chip capacitor:
Class I medium (para-electrics): high voltage resistance, the most stable performance, but low dielectric constant;
Class II medium (ferroelectric): high voltage resistance, higher dielectric constant, but poor capacity temperature stability;
Class III medium (crystal boundary layer): dielectric constant is high, but voltage resistance is low.
There is almost no obvious difference between single layer capacitor and multi-layer chip capacitor based on the same dielectric material, except the size, capacitance and rated operating voltage of capacitors. As for which one to choose, the designer needs to match and select from the layout and size of the circuit board, as well as the actual requirements of capacitance size, capacity, use frequency, voltage, etc., focus on evaluating different capacitors (SLC and MLCC) models, and then find the best product selection based on the simulation evaluation of its overall performance parameters.