Mechanical information
M4T28-BR12SH, M4T32-BR12SH
4
Mechanical information
Electrical connection to the SOIC is made through four pins that connect to the four press
fitted sockets at each end of the SOIC. Critical contact points between the pins and sockets
are gold-plated to resist oxidation. Internally, each socket contains six independent contact
fingers to form redundant connections between the two components. These sockets were
designed with high point contact force to provide the lowest possible contact resistance. The
SNAPHAT
®
top also incorporates four molded-in retaining clips which hold onto the ends of
the SOIC insuring mechanical and electrical connection even under severe mechanical
shock and vibration. The combined SOIC and SNAPHAT assembly can sustain shock levels
in excess of 100 g without separating. This package also passes variable frequency testing
in accordance with MIL-STD-883, method 2007.2, condition A.
illustrates the affect of repeated insertion and extraction of the SNAPHAT top to the
SOIC. The force required to extract the SNAPHAT, and then to re-insert it, reduces each
time. After four or five extractions, the reduction starts to become unnoticeable and the force
required remains at a fairly constant figure. Typically, though, the SNAPHAT will only need to
be extracted and re-inserted once in its lifetime.
Figure 2.
15
SNAPHAT
®
insertion/extraction forces
12.5
Average Insertion
Average Extraction
10
Force (pounds)
7.5
5
2.5
0
1
2
3
4
5
6
7
8
9
10
AI02526
Number of Extractions
8/16
STMICROELECTRONICS [ STMICROELECTRONICS ]
