AMP Circular Connectors for
Commercial Signal and Power Applications
Note:
All part numbers
are RoHS Compliant.
Presentation — An Example*
Current Rating
The presentation of current-
carrying capacity in AMP
product specifications includes
two parts:
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.
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.
10
5
*Note:
Data is
not
typical of a
specific CPC connector configu-
ration. For specific current
rating information based on %
connector loading, contact
Tyco Electronics.
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
[0.6mm
2
] wire.
I
0
0
10
20
30
40
50
60
70
80
Ambient Temperature (°C)
90
100
Graph shows the relationship between base current, ambient
temperature, and contact T-rise.
I
AWG
18
20
22
24
26
From Figure 1, the base
current rating is 14 ampere
with 18 AWG [0.8mm
2
] wire.
Figure 2, the rating factor for
50% loading and 20 AWG
[0.6mm
2
] wire is 0.68.
The specific rating for this
application is the product of
the base rating and the rating
factor:
14 x 0.68 = 9.5 ampere
Each of the contacts can
carry 9.5 ampere.
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
current rating then becomes:
12.8 x 0.68 = 8.7 ampere.
% Loading
Single
1
.83
.69
.59
.50
I
30%
.97
.80
.66
.57
.49
I
Practical Values
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.
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.
50%
.83
.68
.57
.48
.42
I
70%
.65
.53
.45
.38
.33
I
100%
.55
.45
.38
.32
.28
Figure 2
Rating factors allow the base current to be adjusted for various
connector loading and wire sizes.
Contact Selector Chart
Connector
Type
CPC Series 1
CPC Series 2
CPC Series 3
CPC Series 4
CPC Series 5
CPC Series 6
CPC 5015
CMC Series 1
CMC Series 2
CMC Series 3
CMC Series 4
20 DF
Type I
Type II
Type III+
Posted
Type III+
Type XII
Sub-Mini
Coax
POWERBAND
Contacts
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
designed to simplify your choice
Current Rating (Amperes)
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
needed in your choice of
connector, refer to this matrix
for a quick look at exactly what
is acceptable in a given
connector type.
Figure 1
15
Single Contact
18 AWG
9
Catalog 82021
Revised 7-07
www.tycoelectronics.com
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
Canada: 1-905-470-4425
Mexico: 52-55-1106-0800
C. America: 57-1-254-4444
South America: 55-11-2103-6000
Hong Kong: 852-2735-1628
Japan: 81-44-844-8013
UK: 44-208-420-8341
MACOM [ Tyco Electronics ]
