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168
Surface
Heatsink Area Weight Length “L”
Part Number (in
2
/mm
2
) (oz/g) (mm)
C247-025 11 / 7,312 0.5 / 15 25
C247-050 23 / 14,858 1.1 / 31 50
C247-075 34 / 21,655 1.6 / 45 75
C264-030 13 / 8,774 0.7 / 19 30
C264-058 25 / 16,963 1.35 / 37 58
C264-085 37 / 24,861 1.97 / 54 85
C220-025 11 / 7,312 0.5 / 15 25
C220-050 23 / 14,858 1.1 / 31 50
C220-075 34 / 21,655 1.6 / 45 75
C126-025 10.2 / 6,559 0.45 / 12.7 25
C126-040 16.3 / 10,495 0.72 / 20.3 40
C126-050 20.4 / 13,119 0.90 / 25.4 50
C126-075 30.6 / 21,655 1.35 / 38.1 75
Ohmite introduces the C series (Pat. Pending). This
series offers high performance, low cost and a
compact heat sink with an integrated camming clip
system for TO-126, TO-220, TO-247 and TO-264
devices. This powerful heat sink provides tool and
fixture free assembly operation, largest surface areas
and smallest space occupation. It is the ideal type of
heat sink for high power density and small size (1U
or 2U) electronic packaging with forced convection
cooling.
FEATURES
•MinimumassemblycostandlaborSpringClips
make the mounting holes, fasteners, tools and
fixtures obsolete in assembly operations & reduce
costs.
•MaximumThermalTransferMaximumsurfacearea
per unit volume, efficient cooling fins & consistent
mounting force reduces thermal resistance.
•MaximumRepeatabilityConstantspringforceover
repeated assembly/disassembly.
•MaximumReliabilityResilientspringactionlocks
electronic component in place. Fewer parts in
assembly and no fasteners and washers required.
Prevent short circuit by eliminating metal particles
generated from hardware or thread tapping.
•DesignFlexibilityMaximumflexibilityfordynamic
device locations and power upgrading. “Configure-
to-Fit” gives designers total freedom to configure
heat sink needed to fit into a multitude design envi-
ronments.
C Series
TO-126, TO-247, TO-220
and TO-264 Package Heatsinks
CHARACTERISTICS
Heat Sink
Aluminum Alloy 6063-T5 or Equivalent
with either degreased or black anod-
ized finish.
Spring Clip
Music Wire, Per ASTM A228 with
bright nickel plating
Solder Foot
Cold-rolled Steel, Per ASTM A-366
with pure tin over copper strike. RoHS
compliant.
Interface
Thermal
Resistance
for improvement, use thermal joint
compound, 0.005 Grafoil (TGon 800
by Laird), or phase change material
(Hi-Flow by Bergquist)
Insulator
(Optional) Sil-Pad 900-S, K6 800-S
and K10 by Bergquist
SERIES SPECIFICATIONS
HEAT DISSIPATION
Case Temp. Rise above Ambient (°C)
Heat Dissipated, total for ALL devices (watts)
120
80
0
510
100
150
140
Thermal Resistance from Mounting
Case to Ambient (°C/watts)
2
1
0
3
8
7
9
600200 400 1000
60
40
20
5
6
4
Air Velocity (ft./min.)
800
C247-025-1AE (1 device)
C247-050-2AE (2 devices)
C247-075-3AE (3 devices)
HeatdissipationisthetotalforALLDEVICESattachedtoheatsink.
Average Heat Sink Temp. Rise
above Ambient (°C)
Total Heat Dissipated (watts)
36
32
22
6 7 8 9 10
34
2 3 4 5
38
Avg. Thermal Resistance from Mounting
Surface to Ambient (°C/watts)
12
10
600200 400 1000
30
28
24
26
6
8
4
Air Velocity (ft./min.)
800
TO-126/CE-S102 (25mm long)
one device w/Sil-pad 900s
(continued)
