CM3107-00SB CALMIRCO [California Micro Devices Corp], CM3107-00SB Datasheet - Page 11

• Manufacturer Part Number: CM3107-00SB
• Description: 2 Amp Source/ Sink Bus Termination Regulator for DDR Memory and Front Side Bus Applications
• Manufacturer: CALMIRCO [California Micro Devices Corp]

02/02/04
Application Information (cont’d)
PCB Layout Considerations
The CM3107-00SB has a heat spreader attached to
the underneath of the PSOP-8 package in order for
heat to be transferred much easier from the package to
the PCB. The heat spreader is a copper pad of dimen-
sions just smaller than the package itself. By position-
ing the matching pad on the PCB top layer to connect
to the spreader during manufacturing, the heat will be
transferred between the two pads. The drawing below
shows the recommended PCB layout. Note that there
are six vias on either side to allow the heat to dissipate
into the ground and power planes on the inner layers of
© 2004 California Micro Devices Corp. All rights reserved.
VCC (CPU Core)
GMCHVCCP
Figure 20. Front Side Bus Timing diagram
GMCH_EN
430 N. McCarthy Blvd., Milpitas, CA 95035-5112
Table 2: Recommended Heat Sink PCB Layout
L Tel: [phone]
the PCB. Vias can be placed underneath the chip, but
this can cause blockage of the solder. The ground and
power planes should be at least 2 sq in. of copper by
the vias. It also helps dissipation to spread 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 ensure
a thermal link from the CM3107 package to ambient,
θ
JA
Open or "0"
Open or "0"
V
, of around 40°C/W.
DDQSEL
Table 1: V
"1"
L
Fax: [phone]
Note 1:Assumes V
together in DDR application.
TT
Don’t Care
FSBSEL
Output Selection Truth Table.
"0"
"1"
DDQ
L
V
DDQSEL
(Note1)
1.225V
1.45V
V
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and V
TT
/2
DDQSEL
CM3107
For DDR
For FSB
For FSB
NOTE
are tied
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