●RELIABILITY OF TANTALUM CAPACITORS
▶General
The failure rate of the tantalum capacitor varies with the digression ratio, ambient temperature, circuit resistance, circuit application, etc.
Therefore, when proper selections are made so as to afford additional margins, higher reliability can be derived from the tantalum capacitors. Some examples of actual failure rates are presented below for your reference.
▶Failure Rate Calculation Formula
The tantalum capacitors are designed to work at their basic failure
rates shown in Table 3 that prevail when the rated voltage is applied for 1000 hours at 85℃.
Table 3 Basic failure rate
TYPE | C lassification | Basic failure rate |
|
|
|
S C E ,SV E | Low E S R ty pe | |
S C M ,S V M | U | Ty pe(060 3) |
|
|
|
S C L | Low | Ty pe |
S C S ,SV S | S m all Ty pe | |
|
| |
S C N ,S V N | S tanda rd ty pe | |
|
| |
P C * | C ondu c tiv e P oly m er Ty pe | |
1% /10 00h
SCL Series
▷Failure rate calculation formula
λuse = λ85 x KV x KR
λuse : Estimated capacitor failure rate under the operating conditions.
λ85 : Basic failure rate (Table 3)
KV : Failure rate correction coefficient by the ambient temperature and derating factor.
KR : Failure rate correction coefficient by the circuit resistance,
which is the
This resistance is connected in series when the power supply side is viewed from the capacitor side. K(derating factor)=operating voltage/rated voltage
