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|  MIL-R-63993A(AR)
3.4.3 Trimmable resistors R2, R4, R7. The trimmable resistors
shall not be trimmed by the resistor network manufacturer; however,
their initial resistance prior to user laser trimming shall be less
than the minimum specified for their trimmable resistance range.
(See detailed drawing for the trimmable resistance range). The
initial resistance value shall be the nominal resistance used in
the dc resistance tests. The trimmable resistor shall be designed
so that any resistance within its trimmable resistance range shall
be obtainable with a single straight cut made with a YAG Laser set
with a spot size of 2 mils, Q-switched at 3000 pulses
per second, and with power of 1 watt. Windows shall expose all
trimmable material and the substrate around this material as
specified in the detailed drawing.
3.4.4 Voltage sensitivity. The resistance value of the indi-
vidual resistance elements in the network shall not change by more
than 0.5% from its initial value with 1 volt DC applied compared
to the value obtained with 10 volts DC applied. The rated voltage
of the circuit elements shall be 10 volts DC.
3.4.5 Insulation resistance. The insulation resistance
between resistive elements and conductive paths shall be greater
than 3000 megohms.
3.5.1 Marking. Each resistor network shall be marked in
accordance with Method 1 of MIL-STD-1285 as follows:
Part number revision code:
Part number plus revision
letter.
b.
Supplier's code symbol.
c. Inspection lot date code: The first two digits shall be
the last two digits of the number of the year. The third and
fourth digits shall indicate the calendar week of the year.
d.
Pin No. 1 identifier, see Dwg. 9298496.
3.5.2 Resistance to solvents. The markings on resistor net-
,
works shall be legible after being subjected to the resistance to
solvents test of MIL-STD-202, Method 2015.
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