TDK is a well-known supplier of passive components such as their CGA series of MLCC capacitors. We’ve had some question recently concerning issues with this capacitor testing out of tolerance after a long time spent in storage. Is this normal?
For this specific series, TDK recommends a storage time no longer than six months from receipt by the customer. Past this point, and drift can carry the capacitors out of tolerance. Testing methodology also dramatically impacts test results. The full test information for this series can be found here: TDK MLCC Specification Document
Pages 6 and 15 specifically deal with storage conditions and shelf life. The pages in between deal with specific test conditions, which should be adhered to. Testing outside of the supplied test conditions is not considered correct, and may result in incorrect measurements by your QA and testing teams. An ‘out of tolerance’ result from incorrect testing conditions is not necessarily out of tolerance. These devices can experience significant drift under varying frequency, voltages, and temperatures, over and above standard manufacturing tolerance, and should be used and tested in accordance with this knowledge.