APPLICATION NOTES FOR MIL-PRF-55182

1) IMPORTANT! MIL-PRF-55182 has inactivated for new design characteristics C and E (hermetic styles) when used in conjunction with terminal type C (solderable/weldable) only. Characteristics C and E can still be procured with terminal type R (solderable) and type N (weldable). Similarly, MIL-PRF-55182 has inactivated characteristics H, J, and K (non-hermetic styles) when used in conjunction with terminal type R. Characteristics H, J, and K can still be procured with terminal type C and type N.

**  Hermetic resistors (Characteristics C and E) for the MIL-PRF-55182 styles listed in the NPSL are currently only available from Angstrohm.  Previously, Vamistor was a qualified source, but they have dropped their QPL status and are no longer supplying the resistor styles covered in this section of the NPSL.

2) Space Level Product: MIL-PRF-55182 includes a Space Level Quality option designated by the letter "T" in the failure rate level character of the part number. "T" level product receives additional screening and inspection at the manufacturer prior to delivery. This inspection includes additional testing beyond the basic requirements, specifically

In addition, suppliers are required to maintain "S" failure rate level, qualify product through 100 thermal cycles and certify that their product meets the outgassing requirements of NASA Publication 1124. Consult with the supplier to determine their current "T" level qualification status.

3) For RNC90Y resistors any resistance value may be ordered within the ranges listed in the selection list tables.  However, it is preferred that resistance values be selected from the standard decade values shown in the listings herein.

4)  RNC90Y resistors should ONLY be used in applications where their particular characteristics of

are ABSOLUTELY necessary.  There are known reliability concerns with these resistors resulting from the difficulty making robust connections to the thin nichrome foil used in their construction.
 
5)  A qualified source exists for RNC90Y resistors up to 121 kohms.  However, RNC90Y values above 100 kohms are not suggested for space flight use.  The thin foils required for values above 100 kohms and the complexity of the grid line pattern in the resistive foil make resistors with these high values difficult to produce with a reliability satisfactory for space flight applications.  MIL-PRF-55182/9 does not include values below 4.99 ohms.  There are no known additional risks associated with the construction of parts below 4.99 ohms, however, long term reliability test data is not maintained for these values.
 
6)  All styles of MIL-PRF-55182 resistors are sensitive to Electrostatic Discharges (ESD) except for RNC90Y.