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© KEMET Electronics Corporation • KEMET Tower • One East Broward Boulevard

C1070_C0G_HV_FT-CAP_SMD • 2/28/2023

Fort Lauderdale, FL 33301 USA • 954-766-2800 • www.kemet.com

Surface Mount Multilayer Ceramic Chip Capacitors (SMD MLCCs)

High Voltage with Flexible Termination System (HV FT-CAP), C0G Dielectric, 500 – 10,000 VDC (Commercial Grade)

Application Guide

Solder Fluxes and Cleaning

The use of water-soluble fluxes provides advantages of excellent solderability due to high activation. However, these fluxes

contain organic acids that can induce arcing under high DC or AC voltages. Notable problem areas are underneath the MLCC

where flux can be trapped between the ceramic material and PCB. It is therefore critical that PCBs are properly cleaned to

remove all flux residue to maintain reliability.

Coating for High Voltage MLCCs

For MLCC ratings ≥1500V, it is recommended to apply a conformal coating to MLCC to prevent surface arcing. To reduce

possibility of inducing cracks in the MLCC, select a coating with thermal expansions close to that of the MLCC.

Dielectric

CTE (ppm/°C)

Class II BaTiO

3

10.7

Class I CaZrO

3

9.8

Slits in PCB

It is recommended to apply a slit in the PCB under the MLCC to improve washing of flux residue that may get trapped

underneath. In some cases, it is not possible to slit entirely through the PCB due to underlying metal planes. It is also

acceptable to apply a recessed slit under the MLCC which will also promote cleaning.

• Recommended for case sizes ≥1206

• The width (w) of the slit should be 1mm

• Length of the slit should be as short as possible to prevent damaging the MLCC due to mechanical stress of the PCB.

• Slits also reduce the risk of solder balls under MLCC which decreased the creepage distance.

Solder Resist

If a slit cannot be applied as above, it is recommended to not use solder resist directly under the MLCC. The use of solder

resist material reduces the distance between MLCC ceramic material and PCB thus making it difficult to clean.

Solder Balls

Improper reflow techniques and/or improper washing can induce solder balls under or adjacent to the MLCC. Solder balls

reduce the creepage distance between the MLCC terminations and increase the risk of arcing or damage to the ceramic

material. To reduce the risk of solder balls:

• Follow KEMET’s solder recommendations as outlined in the datasheet.

• If performing a cleaning procedure, properly clean the PCB per KEMET’s cleaning recommendations.

• Add slit to the PCB as shown above.