NOTE: All part numbers
are RoHS Compliant
AMP M Series
Pin and Socket Connectors
Contract Carrying Capabilities
The total current capacity of
each contact in a given con-
nector is dependent upon the
heat rise resulting from the
combination of electrical
loads of the contacts in the
connector arrangement and
the maximum ambient tem-
perature in which the
connector will be operating.
Caution must be taken to
ensure that this combination
of conditions does not cause
the internal temperature of
the connector to exceed the
maximum operating temper-
ature of the housing material.
Several variables which must
be considered when deter-
mining this maximum current
capability for your applica-
tion are:
CONTACT CURRENT GUIDE Maximum Current (Amperes)
75
60
45
30
15
Type XII Upgrade
Size 8 Upgrade
60
56
50
.125 POWERBAND
Contact
45
Size 8
35
Type XII
+
Type I, Type II/III
Upgrade
23
+
Type III , Type II,
+
Type III Posted
13
11.85
Size 20 Upgrade
20 DF
7.5
0
Current Load Distribution - Ambient Temperature -
Connector Size - In general,
with more circuits in a con-
nector, less current per
Wire Size - Larger wire will
carry more current since it
has less internal resistance
to current flow and gener-
ates less heat. The wire also
conducts heat away from
the connector.
Spreading those lines with
greater current loads
through-out the connector,
particularly around the
outer perimeter, will
With higher ambient
temperatures, less current
can be carried.
contact can be carried.
enhance heat dissipation.
Current Rating Verification
Can a contact rated at 10
amps carry 10 amps?
Maybe yes, but probably not.
The reason lies in the test
conditions used to rate the
contact. If these conditions
do not adequately reflect the
application conditions, the
actual allowable current lev-
els may be lower than
specified levels. For example,
many manufacturers, includ-
ing Tyco, test a single contact
in air. This gives an accurate
measure of the basic current-
carrying capacity of the
contact. Use the contact
alone in air and it can cer-
tainly carry 10 amperes. Use
it in a multi-position connec-
tor surrounded by other
current-carrying contacts or
in high ambient temperatures,
and the contact should carry
less current.
Practical current-carrying
capacity is not an absolute,
but an application-dependent
condition.
Temperature
containing 50% current-carry-
ing contacts will permit higher
currents (per contact) than a
connector will at 75% loading.
The loading percentage
assumes an even distribution
of contacts within the housing.
If all 10 contacts are grouped
together in one section of a
20-position
One other factor influencing
current levels is the maximum
operating temperature, for
example, 105°C. If the appli-
cation has a high ambient
temperature (over 75°C) the
contact’s T-rise is limited by
the maximum operating tem-
perature. For example, an
application temperature of
90°C limits the contact T-rise
to 15°C. Since current pro-
New Method Simplifies
Ratings
To help the designer set the
appropriate current level,
Tyco has developed a
method of specifying cur-
rent-carrying capacity. This
method takes into account
the various application fac-
tors that influence current
rating.
connector, the loading density
may approach 100%.
The Importance of EODL
2
duces heat (the I R law), the
current must be lowered to
limit the T-rise.
As stated, T-rise in a contact
depends on both resistance
and current. As it ages, a con-
tact’s resistance will increase.
The contact designer will
specify a maximum resistance
for the contact, this level is the
end-of-design-life resistance.
Before the contact is tested
for current, Tyco subjects it to
a sequence of tests that exer-
cises the major failure
mechanisms and thereby sim-
ulates EODL conditions.
Conditioning includes mating
cycling, industrial mixed-flow-
ing gases, humidity and
The method can be summa-
rized as follows:
A contact’s T-rise depends
not only on its I R Joule heat-
2
ing, but also on its ability to
dissipate the heat. Consider a
contact in a multi-contact
housing. Joule heating in
multiple contacts will raise
the local ambient tempera-
ture. Since the contact will
not be able to dissipate its
own heat as well by convec-
tion, the maximum T-rise will
be realized at a lower current
level. Conse-quently, the
allowable current level must
be lower to maintain an
The contact is aged to
EODL conditions by durabil-
ity cycling, thermal cycling,
and environmental expo-
sure.
The contact’s resistance
stability is verified.
The current necessary to
produce the specified tem-
perature rise is measured.
This T-rise is usually 30°C.
Similarly, as the contact ages
and stress relaxation, environ-
mental cycling, and other
degradation factors take their
toll, the contact’s current-
carrying capacity decreases.
A prudent design must set
current levels for such end-of-
design-life (EODL) conditions.
A rating factor is deter-
mined to allow derating of
multiple contacts in the
same housing and for differ-
ent conductor sizes.
tempera-ture cycling, and
vibration to sequentially
introduce wear, corrosion,
stress relaxation, and
acceptable T-rise.
For a given connector, the
current level will be set by the
loading density. A connector
mechanical disturbance.
7
Catalog 82003
Revised 06-08
Dimensions are in millimeters
and inches unless otherwise
Dimensions are shown for
USA: 1-800-522-6752
South America: 55-11-3611-1514
Hong Kong: 852-2735-1628
Japan: 81-44-844-8013
UK: 44-141-810-8967
reference purposes only.
Specifications subject
to change.
Canada: 1-905-470-4425
Mexico: 01-800-733-8926
C. America: 52-55-5-729-0425
specified. Values in brackets are
equivalent U.S. Customary Units.
www.tycoelectronics.com
MACOM [ Tyco Electronics ]
