2) For Level 1 applications MIL-PRF-55365 capacitors should be subjected to either option "B" or "C" surge current testing (at -55°C and +85°C) in accordance with MIL-PRF-55365 and associated slash sheet. For Level 2 applications MIL-PRF-55365 capacitors should be subjected to option "A" surge current testing (at +25°C) as specified by MIL-PRF-55365 and associated slash sheet. For Level 3 applications MIL-PRF-55365 capacitors used in single point failure or mission critical locations should be subjected to option "A" surge current testing (at +25°C). NOTE: MIL-PRF-55365 and slash sheets provide the procuring activity the option to order capacitors with any of 3 different surge current tests performed on 100% of the capacitors as part of the manufacturer's outgoing conformance inspection. See the MIL spec or the part number ordering explanation table for details.
3) These tantalum capacitors are polar devices that are sensitive to reverse bias voltage. Prolonged exposure to high levels of reverse voltage can produce very high leakage currents and short circuits. Short circuited tantalum capacitors can ignite and/or produce excessive heat resulting in extreme damage to circuit boards. Reverse bias application of these parts should be avoided. MIL-PRF-55365 offers no guidance on the reverse bias performance of these capacitors. Capacitor manufacturer guidelines are generally very conservative urging against any prolonged exposure to reverse bias. Some limited experimental data exists that suggests some capacitors may be able to indefinitely withstand room temperature reverse voltages on the order of 15 to 25% of rated voltage. However, all of the factors affecting the reverse bias behavior (including size and rating of the capacitor, effects of circuit current limiting and ambient temperature) have not been studied. Refer to NEPAG Lesson Learned Bulletin NEPAG-LLB-2001-002 and NEPAG Study Report "Reverse Bias Behavior of Surface Mount Solid Tantalum Capacitors" for further details.
4) Users are urged to carefully confirm the proper orientation of all tantalum capacitors after installation. The convention for polarity markings is often a source of potential confusion. "Chip" tantalum capacitor styles are prone to being installed improperly because they may be very small and the polarity identifier can be difficult to see. Polarity idenitifcation for CWR06 capacitors may be particularly difficult to see. Polarity for these devices is determined by a small protrusion of the anode riser wire from the anode ("+") termination end cap.
Historically, reverse polarity failures have been observed that resulted from:
Refer to NEPAG Lesson Learned Bulletin NEPAG-LLB-2001-002 for further details