611073-000 Tyco Electronics, 611073-000 Datasheet - Page 40

• Manufacturer Part Number: 611073-000
• Description: Connector Accessories Adapter Aluminum Alloy Olive Drab Cadmium Over Electroless Nickel
• Manufacturer: Tyco Electronics
• Type: Adapterr

2-22
Table 5 - Screening
Effectiveness (SE)/Surface
Transfer Impedance (Zt)
Relationships
Catalog 1654025
Revised 12-04
www.tycoelectronics.com
Dimensions are in millimeters
and inches unless otherwise
specified. Values in brackets
are U.S. equivalents.
Electrical Interconnection System Design
Integrated Military Harness Systems for Defense and Allied Industries
Safety Margins
As with all designs EMI sys-
tem design should not be
performed to the “limit of
performance safety margin
should always be incorpo-
rated when determining the
minimum shielding level
appropriate for consistent
operation of the system.
The inter-relationship of
shielding effectiveness
measured in decibels and
the surface transfer imped-
ance in ohms presents the
designer with a conversion
difficulty. External harness
circuits vary, as do the cou-
pling characteristics and it
is therefore only possible to
give an approximate con-
version. The normal conver-
sion from decibels to ohms
and vice versa is to a rea-
sonable approximation:
Screening Effectiveness
(dB) = 36 – 20 log
The constant term is devel-
oped from the expressions
for the characteristic imped-
ance of the line formed by
the harness shield and the
ground plane and the inter-
nal characteristic imped-
ance of the inside of the
harness. The translation
from shielding effectiveness
to surface transfer imped-
ance is shown below in
Table 5 for S.E. from 20 to
105dB.
S.E. (dB)
20
25
30
35
40
45
50
55
60
10
Dimensions are shown for
reference purposes only.
Specifications subject
to change.
(Z
T
(Ohms))
Z
T
6.309
3.548
1.995
1.122
0.631
0.355
0.200
0.112
0.063
(ohms)
Connectors
A study of those connector
specifications having an
EMI test shows that they are
generally specified in the
frequency band 100MHz to
1GHz. For an assessment at
lower frequencies the low
frequency performance
as dictated by the d.c.
resistance of the connector
is required. These two
parameters enable the EMI
characteristic to be made
of the complete connector
performance. Typical values
for standard connectors are
65dB (MIL-C-26482 Series II)
and 90dB (MIL-C-38999
Series III) connectors.
USA: 1-800-522-6752
Canada: 1-905-470-4425
Mexico: 01-800-733-8926
C. America: 52-55-5-729-0425
S.E. (dB)
100
105
65
70
75
80
85
90
95
South America: 55-11-3611-1514
Japan: 81-44-900-5102
Singapore: 65-4866-151
UK: 44-1793-528171
(Continued)
Z
0.0355
0.0200
0.0112
0.0063
0.0036
0.0020
0.0011
0.0006
0.0004
T
(ohms)