APPLICATION NOTES S-311-P-813
1) GSFC's S-311-P-813 specification
was developed to enable procurement of Space Level precision resistors.
Special qualification and screening provisions have been included in this
specification for space application considerations. Included in this
processing are a special power conditioning test and the option to require
conformance to Current Noise, Voltage Coefficient and Thermal EMF test
limits.
2) This part is similar in form, fit
and function to the RNC90Y resistors from MIL-PRF-55182/9 and the MIL-R-122/1
resistors. It is anticipated that the only qualified source for MIL-R-122/1
will drop their qualification in favor of providing parts to DSCC drawing
versions of this device. The DSCC drawings will not be Established
Reliability specifications requiring routine failure rate maintenance testing.
3) Parts procured in accordance with GSFC
S-311-P-813 are acceptable for Level 1 or
Level 2 applications.
4) Parts of 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.
5) These S-311-P-813 resistors
should ONLY be used in applications where their particular characteristics
of
-
Tight temperature coefficient
-
Minimal resistance drift over
time
-
Precision
-
High power rating for package
density
are ABSOLUTELY necessary.
There are possible reliability concerns with these resistors resulting
from the difficulty making robust connections to the thin nichrome foil
used in their construction.
6) S-311-P-813 does
NOT include resistors above 100 kohms. 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.