Model 4431T Shielded Bag Test System - Operating Manual
11
D00003 Rev. K.
The current pulse detected between the upper and lower electrodes of the capacitive probe is used to
calculate the energy inside the bag. Figure 4-3 shows the raw data in milliAmps from the current sensor.
This is the customary way to view and compare bag performance. From this data, the total energy in
nanoJoules is computed.
Figure 4-3: Typical Model 4431-T shielded bag waveform
For S11.31, six specimens (samples) of a given product are required. Six measurements per specimen
is specified. Testing is to be performed at both 12% and 50% ±3% RH at a temperature of 73
±3 ºF
(23 + 2 ºC) after a conditioning period of 48 hours minimum. Bag size for this test is specified to be 8
x 10 inches (20 x 25 cm).
ANSI/ESD S11.31 specifies that the test conditions, peak current, minimum, maximum and average
energy levels of all 36 measurements be reported for bag qualification.
4.2
ANSI/ESD S11.4 Static Control Bags
This standard defines the performance of static shielding bags used in manufacturing and commercial
applications. It defines an acceptable bag as having
<20nJ
when tested in accordance with S11.31.
4.3
MIL PRF 81705E
This military standard defines the performance of Type 1 water-vapor proof and Type 3 static shielding
bags. The acceptable energy limit when tested in accordance with S11.31 is
<10nJ
.
T, nsec
100 200 300 400 500
