2) Parts covered by this specification contain internal soldered connections which may reflow during installation. The A, A1, B, B1 case sizes are particularly susceptible and special precautions such as heat sinking are recommended when soldering onto boards.
3) For Level 1 applications all CSR13 and CSR09 capacitors should be subjected to the surge current test as specified by MIL-PRF-39003/10 (surge current testing at -55°C, +25°C and +85°C). For Level 2 applications all CSR13 and CSR09 capacitors should be subjected to the surge current test as specified by MIL-PRF-39003/9 (surge current testing at +25°C). For Level 3 applications all CSR13 and CSR09 capacitors used in single point failure or mission critical locations should be subjected to the surge current testing as specified by MIL-PRF-39003/9 (surge current testing at +25°C).
4) M39003 style capacitors rated at 100 V and higher are NOT recommended for use and are therefore NOT listed within the NPSL. Historically, the NPSL has NOT listed capacitors with these ratings. In order to produce the higher voltage ratings the manufacturers use alternate process steps compared to the lower voltage styles. These alternate process steps have not been found to consistently produce reliable parts.
5) 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-39003 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.
6) 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. Historically, reverse polarity failures have been observed that resulted from:
Part marking for MIL-PRF-39003/10 tubular case capacitors requires a stripe on the case adjacent to the cathode ("-") termination. This convention can be a source for confusion because the surface mount molded tantalum "chip" capacitors (CWR09 types per MIL-PRF-55365/4) frequently use a stripe on the case to identify the anode ("+") termination. Generally, the other styles of tubular case tantalum capacitors use a "+" to identify the anode terminal.
Refer to NEPAG Lesson Learned Bulletin NEPAG-LLB-2001-002 for further details