LMK01000ISQ NSC [National Semiconductor], LMK01000ISQ Datasheet - Page 16

• Manufacturer Part Number: LMK01000ISQ
• Description: 1.6 GHz High Performance Clock Buffer, Divider, and Distributor
• Manufacturer: NSC [National Semiconductor]

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3.3 THERMAL MANAGEMENT
Power consumption of the LMK01000/LMK01010/LMK01020
can be high enough to require attention to thermal manage-
ment. For reliability and performance reasons the die tem-
perature should be limited to a maximum of 125 °C. That is,
as an estimate, T
consumption times θ
The package of the device has an exposed pad that provides
the primary heat removal path as well as excellent electrical
grounding to the printed circuit board. To maximize the re-
moval of heat from the package a thermal land pattern in-
cluding multiple vias to a ground plane must be incorporated
on the PCB within the footprint of the package. The exposed
pad must be soldered down to ensure adequate heat con-
duction out of the package. A recommended land and via
pattern is shown in Figure 2. More information on soldering
LLP packages can be obtained at www.national.com.
A
(ambient temperature) plus device power
JA
should not exceed 125 °C.
FIGURE 2.
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To minimize junction temperature it is recommended that a
simple heat sink be built into the PCB (if the ground plane
layer is not exposed). This is done by including a copper area
of about 2 square inches on the opposite side of the PCB from
the device. This copper area may be plated or solder coated
to prevent corrosion but should not have conformal coating (if
possible), which could provide thermal insulation. The vias
shown in Figure 2 should connect these top and bottom cop-
per layers and to the ground layer. These vias act as “heat
pipes” to carry the thermal energy away from the device side
of the board to where it can be more effectively dissipated.