CM3196 Datasheet, PDF (11/13 Pages) California Micro Devices Corp – 2A Sink/Source DDR-I, -II Bus Termination Regulator

CM3196
Application Information
PCB Layout Considerations
The CM3196-12SB has a heat spreader attached to
the underneath of the PSOP-8 package in order for
heat to be transferred 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 manufacturing, the heat will be trans-
ferred 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
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
adjacent to the vias. It also helps if the chip is posi-
tioned 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 properly
couple the CM3196 package to maintain an ambient
junction temperature (θ_JA) of around 40°C/W.
Figure 15. Recommended Heat Sink PCB Layout
SD
V_DDQ
AV_IN
PV_IN
CAV_IN
47µF
SD
V_DDQ
AV_IN
PV_IN
CPV_IN
47µF
V_REF
V_SENSE
V_TT
GND
V_REF
C_VREF
0.1µF
V_TT
C_Vout
220µF
Figure 16. Typical Application Circuit
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