KEMET SMD (Surface Mounted Device) tantalum capacitors are easy to be
identified by the KEMET ID symbol, the capital "K" letter above- and
underlined. Just in case, it's shown in the top part of this page. KEMET is one
of the world's largest manufacturers of tantalum capacitors together with AVX
and Vishay, so their capacitors may be found probably in any kind of hardware
ranging from consumer electronics to military/aerospace equipment. Although
tantalum capacitors are expensive considerably, they're useful for various DIY
projects, salvage and repair jobs, etc. Of course, if you buy a whole reel of
such capacitors, you can find the series code printed on the label and pick up
the respective data sheet online within a few minutes. But what to do, for
instance, if you've salvaged some tantalum capacitors from some kind of old or
dead equipment? You need to identify them before re-using, and your only
information source is a few markings which may be found on the top side of any
SMD tantalum capacitor. So, here we start.
The picofarad code refers to capacitance indeed. In particular, 226 stands
for 22*10^6 picofarads, i.e. 22 microfarads. Rated voltage is in volts, and
manufacturing date is in year-week format. Although SMD tantalum capacitors of
different series and case sizes may feature different date formats. By the way,
don't forget that 542 as illustrated above may refer to the 42nd week of either
1995 or 2005. Once finished with the initial identification, we have to find
out the series a particular capacitor belongs to. It's a very important step
because tantalum capacitors with the same capacitance and voltage rating but
assigned to different series may have very different characteristics. KEMET
assigns different polarity indicators to different series, so we have to find
a visual match.
Polarity indicator |
Series |
Grade |
 |
T491 |
Industrial |
 |
T492 |
Military |
 |
T493 |
Military (COTS) |
 |
T493 or T497 (both Space Grade) |
T493: Military and Aerospace (COTS)
T497: Military and Aerospace (High Grade COTS) |
 |
T494 |
Industrial (Low ESR) |
 |
T495 |
Industrial (Low ESR, Surge Robust) |
 |
T496 |
Industrial (Fail-Safe Fused) |
 |
T496 (Space Grade) |
Aerospace (Fail-Safe Fused) |
 |
T498 |
Industrial (High Temperature: 150°C) |
 |
T499 |
Industrial (High Temperature: 175°C) |
 |
T510 |
Industrial (Low ESR, High Capacitance) |
 |
T510 (Space Grade) |
Aerospace (Low ESR, High Capacitance) |
 |
T520 or T521 |
T520: Industrial (Low ESR)
T521: Industrial (Low ESR, High Voltage)
[Conductive Polymer Cathode] |
 |
T525 |
Industrial (Low ESR, High Temperature: 125°C)
[Conductive Polymer Cathode] |
 |
T528 |
Industrial (Low ESR, Low ESL)
[Conductive Polymer Cathode] |
 |
T530 |
Industrial (Very Low ESR, High Capacitance)
[Conductive Polymer Cathode] |
COTS stands for Commercial Off The Shelf which means high reliability
industrial products. These are usually more expensive than regular industrial
products, but much less expensive than top quality military products (MIL-ER,
MILitary - Established Reliability). The MIL-ER products must pass through a
defined set of testing conditions. Their failure rates must be published and
not to exceed those defined by a military standard. In particular, solid
tantalum capacitors for U.S. military use must conform to MIL-PRF-39003 and
MIL-PRF-49137.
Note that KEMET has acquired a tantalum capacitor business from EPCOS in
December of 2005. Therefore, EPCOS capacitors which have been manufactured
after the acquisition carry the KEMET ID symbol, but their marking system
remains different. Well, now follow to the next page and pick up the data sheet
you need.