Note: All part numbers
are RoHS Compliant.
AMP Circular Connectors for
Commercial Signal and Power Applications
Presentation — An Example*
Current Rating
of connectors and their accept-
able contacts. Once you have
selected the wire size, current-
carrying capacity need,
number of positions required,
and the type of contacts
The presentation of current-
carrying capacity in AMP
product specifications includes
two parts:
Figure 1
15
Single Contact
18 AWG
I First, a base curve showing
current levels versus T-rise for
a single circuit and the largest
wire size (See figure 1). This
represents the maximum
current capacity of the
contact. The curve is usually
flat up to 75°C ambient and
then drops off. Up to 75°C, the
30°C T-rise limits the amount
of current, and above 75°C
the current must be reduced
to keep the combination of
ambient temperature and
T-rise from exceeding the
maximum operating tempera-
ture of 105°C.
needed in your choice of
connector, refer to this matrix
for a quick look at exactly what
is acceptable in a given
10
5
connector type.
*Note: Data is not typical of a
specific CPC connector configu-
ration. For specific current
rating information based on %
connector loading, contact
Tyco Electronics.
0
0
10
20
30
40
50
60
70
80
90
100
Ambient Temperature (°C)
Graph shows the relationship between base current, ambient
temperature, and contact T-rise.
To demonstrate the method of
specifying current, consider the
following application conditions;
an ambient temperature of 65°C,
a 50% loading of contacts in
the housing, and 20 AWG
I Next are rating factors, a
table of multipliers to account
for connector loading and for
smaller wire sizes (See figure 2).
The designer first determines
the base current for the
ambient conditions of the
application; then multiplies
this base current by the rating
factors to find the current
level for the application’s
loading factor and wire size.
AWG
2
[0.6mm ] wire.
18
1
20
.83
.80
.68
.53
.45
22
.69
.66
.57
.45
.38
24
.59
.57
.48
.38
.32
26
.50
.49
.42
.33
.28
I From Figure 1, the base
current rating is 14 ampere
2
with 18 AWG [0.8mm ] wire.
Single
30%
I Figure 2, the rating factor for
50% loading and 20 AWG
2
[0.6mm ] wire is 0.68.
.97
.83
.65
.55
I The specific rating for this
application is the product of
the base rating and the rating
factor:
Practical Values
50%
The current-rating method
gives designers practical
values applicable to their appli-
cations. While the specified
current levels for a contact may
be lower than for other testing
methods, they are more practi-
cal and simplify the system
design process.
“Spec-manship” is replaced
by a realistic assessment of the
current-carrying capacity of a
contact under varying condi-
tions of temperature, connector
loading, and wire size.
14 x 0.68 = 9.5 ampere
I Each of the contacts can
carry 9.5 ampere.
70%
I
However, if the ambient temper-
ature is 80°C the allowable
T-rise becomes 25°C. The base
current must be lowered to
12.8 ampere so that the 105°C
maximum operating tempera-
ture is not exceeded. The
100%
Figure 2
current rating then becomes:
12.8 x 0.68 = 8.7 ampere.
Rating factors allow the base current to be adjusted for various
connector loading and wire sizes.
Specific current-carrying data
based on EOL and % loading is
available from Tyco Electronics.
Please contact your local
Tyco Electronics Sales Engineer
or call Tyco Electronics.
Contact Selector Chart
Connector
20 DF
Posted
Sub-Mini POWERBAND
Type I
Type II
Type III+
Type XII
Type
Type III+
Coax
Contacts
CPC Series 1
ꢀ
ꢀ
ꢀ
ꢀ
CPC Series 2
CPC Series 3
CPC Series 4
CPC Series 5
CPC Series 6
CPC 5015
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Connector/Contact Acceptability
ꢀ
ꢀ
As previously stated, choosing
the correct connector/contact
combination is fundamental
to the successful function of
all connectors. The Selector
Chart shown at right, is
ꢀ
ꢀ
ꢀ
ꢀ
CMC Series 1
CMC Series 2
CMC Series 3
CMC Series 4
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
designed to simplify your choice
9
Catalog 82021
Revised 7-07
Dimensions are in inches and
millimeters unless otherwise
specified. Values in brackets
are metric equivalents.
Dimensions are shown for
reference purposes only.
Specifications subject
to change.
USA: 1-800-522-6752
South America: 55-11-2103-6000
Hong Kong: 852-2735-1628
Japan: 81-44-844-8013
Canada: 1-905-470-4425
Mexico: 52-55-1106-0800
C. America: 57-1-254-4444
www.tycoelectronics.com
UK: 44-208-420-8341
MACOM [ Tyco Electronics ]
