CM3202-00 California Micro Devices Corporation, CM3202-00 Datasheet - Page 9

• Manufacturer Part Number: CM3202-00
• Description: Ddr Vddq And Termination Voltage Regulator
• Manufacturer: California Micro Devices Corporation

Application Info (cont’d)
condition can be estimated by the following thermal
equation:
When a CM3202 is mounted on a double-sided printed
circuit board with four square inches of copper allo-
cated for “heat spreading,” the θ
55°C/W. Based on the over temperature limit of 170°C
with an ambient of 85°C, the available power of the
package will be:
© 2006 California Micro Devices Corp. All rights reserved.
08/16/06
P
D
T
JUNC
=
170° C 85° C
------------------------------------ -
55° C
=
=
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
T
T
AMB
AMB
–
⁄
W
+
+
P
P
D
D
=
×
×
1.5W
Note: This drawing is not to scale
(
(
θ
Ground Plane
θ
Bottom Layer
CA
JC
)
)
+
P
D
×
JA
(
θ
CA
is approximately
)
Vias (0.3mm Diameter)
Top View
Figure 2. Thermal Layout
Connects to Heat Spreader
●
Tel: [phone]
Top Layer Copper
PCB Layout Considerations
TheCM3202 has a heat spreader attached to the bot-
tom of the TDFN-8 package in order for the heat to be
transferred more easily from the package to the PCB.
The heat spreader is a copper pad of dimensions just
smaller than the package itself. By positioning the
matching pad on the PCB top layer to connect to the
spreader during the manufacturing, the heat will be
transferred between the two pads. See the
the CM3202 shows the recommended PCB layout.
Please be noted that there are four vias on either side
to allow the heat to dissipate into the ground and power
planes on the inner layers of the PCB. Vias can be
placed underneath the chip, but this can be resulted in
blocking of the solder. The ground and power planes
need to be at least 2 square inches of copper by the
vias. It also helps dissipation if the chip is positioned
away from the edge of the PCB, and not near other
heat-dissipating devices. A good thermal link from the
PCB pad to the rest of the PCB will assure the best
heat transfer from the CM3202 to ambient,
approximately 55°C/W.
●
Pin Solder Mask
Fax: [phone]
Thermal PAD
Solder Mask
PRELIMINARY
●
www.cmd.com
CM3202
Figure
θ
JA
, of
2,
9