
7
MC100EP222
MOTOROLA ADVANCED CLOCK DRIVERS DEVICE DATA
655
APPLICATIONS INFORMATION
Using the thermally enhanced package of the
MC100EP222
The MC100EP222 uses a thermally enhanced exposed pad
(EP) 52 lead LQFP package. The package is molded so that
the leadframe is exposed at the surface of the package bottom
side. The exposed metal pad will provide the low thermal im-
pedance that supports the power consumption of the
MC100EP222 high-speed bipolar integrated circuit and eases
the power management task for the system design. A thermal
land pattern on the printed circuit board and thermal vias are
recommended in order to take advantage of the enhanced
thermal capabilities of the MC100EP222. Direct soldering of
the exposed pad to the thermal land will provide an efficient
thermal path. In multilayer board designs, thermal vias ther-
mally connect the exposed pad to internal copper planes.
Number of vias, spacing, via diameters and land pattern de-
sign depend on the application and the amount of heat to be
removed from the package. A nine thermal via array, arranged
in a 3 x 3 array and using a 1.2 mm pitch in the center of the
thermal land is the absolute minimum requirement for
MC100EP222 applications on multi-layer boards. The recom-
mended thermal land design comprises a 5 x 5 thermal via
array as shown in Figure 6 “Recommended thermal land pat-
tern”, providing an efficient heat removal path.
7
Figure 6. Recommended thermal land pattern
Thermal via array (5x5),
1.2 mm pitch,
0.3 mm diameter
Exposed pad
land pattern
all units mm
7
The via diameter is should be approx. 0.3 mm with 1 oz.
copper via barrel plating. Solder wicking inside the via resulting
in voids during the solder process must be avoided. If the cop-
per plating does not plug the vias, stencil print solder paste
onto the printed circuit pad. This will supply enough solder
paste to fill those vias and not starve the solder joints. The
attachment process for exposed pad package is equivalent to
standard surface mount packages. Figure 7 “Recommended
solder mask openings” shows a recommend solder mask
opening with respect to the recommended 5 x 5 thermal via
array. Because a large solder mask opening may result in a
poor release, the opening should be subdivided as shown in
Figure 7 For the nominal package standoff 0.1 mm, a stencil
thickness of 5 to 8 mils should be considered.
Exposed pad
land pattern
7
Figure 7. Recommended solder mask openings
Thermal via array (5x5),
1.2 mm pitch,
0.3 mm diameter
1.0
0.2
all units mm
7
1.0
0.2
For thermal system analysis and junction temperature cal-
culation the thermal resistance parameters of the package is
provided. For thermal system analysis and junction tempera-
ture calculation the thermal resistance parameters of the pack-
age is provided:
Table 8: Thermal Resistancea
Convection-
LFPM
RTHJAb
°C/W
RTHJAc
°C/W
RTHJCd
°C/W
RTHJBe
°C/W
Natural
57.1
24.9
100
50.0
21.3
200
46.9
20.0
15.8
9.7
400
43.4
18.7
800
38.6
16.9
a. Thermal data pattern with a 3 x 3 thermal via array on
2S2P boards (based on empirical results)
b. Junction to ambient, single layer test board, per JESD51-6
c. Junction to ambient, four conductor layer test board
(2S2P), per JES51-6
d. Junction to case, per MIL-SPEC 883E, method 1012.1
e. Junction to board, four conductor layer test board (2S2P)
per JESD 51-8
It is recommended that users employ thermal modeling
analysis to assist in applying the general recommendations to
their particular application. The exposed pad of the
MC100EP222 package does not have an electrical low imped-
ance path to the substrate of the integrated circuit and its termi-
nals. The thermal land should be connected to GND through
connection of internal board layers.