NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.


ESD: A Tale of Two Lids

The two lids shown here are from the same socket manufacturer (Enplas) and appear the same.  However, testing and examination shows that they are substantially different in ESD performance.  Data courtesy of Actel Corporation.

“ESD Friendly” Lid

 

“ESD Not So Friendly” Lid

V < ± 15V

V > 1100V

 

FIELD READINGS ON TEST SOCKET LIDS

Lids as Received

  ESD Unfriendly ESD Friendly
1 3600V+ <15V
2 7100V+ <15V
3 3400V+ <15V
4 2400V+ <15V
5 5400V+ <15V
6 5300V+ <15V
7 1900V+ <15V

 

NASA (Materials Department) Lid Evaluation.

  ESD Unfriendly ESD Friendly
Point to Point Resistance (ohms) 1 x 1013 4.4 x 106
Conclusion (ANSI/ESD S541-2003) Insulative Static Dissipative

Note: At the time of this writing, there is no known way to determine the composition of the lid by visual inspection.  I have submitted some suggestions to make the two lids visually identifiable and have distinct part numbers.


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Last Revised: February 03, 2010
Digital Engineering Institute
Web Grunt: Richard Katz
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