AMIS−30521, NCV70521
http://onsemi.com
5
PACKAGE THERMAL CHARACTERISTICS
The AMIS−30521/NCV70521 is available in an
NQFP−32 package. For cooling optimizations, the NQFP
has an exposed thermal pad which has to be soldered to the
PCB ground plane. The ground plane needs thermal vias to
conduct the heat to the bottom layer. Figure 3 gives an
example for good power distribution solutions.
For precise thermal cooling calculations the major
thermal resistances of the device are given. The thermal
media to which the power of the devices has to be given are:
• Static environmental air (via the case)
• PCB board copper area (via the exposed pad)
The thermal resistances are presented in Table 5: DC
Parameters.
The major thermal resistances of the device are the Rth
from the junction to the ambient (R
thja
) and the overall Rth
from the junction to exposed pad (R
thjp
). In Table 3 one can
find the values for the R
thja
simulated according to
JESD−51.
The R
thja
for 2S2P is simulated conform JEDEC JESD−51
as follows:
• A 4−layer printed circuit board with inner power planes
and outer (top and bottom) signal layers is used
• Board thickness is 1.46 mm (FR4 PCB material)
• The 2 signal layers: 70 mm thick copper with an area of
5500 mm
2
copper and 20% conductivity
• The 2 power internal planes: 36 mm thick copper with
an area of 5500 mm
2
copper and 90% conductivity
The R
thja
for 1S0P is simulated conform JEDEC JESD−51
as follows:
• A 1−layer printed circuit board with only 1 layer
• Board thickness is 1.46 mm (FR4 PCB material)
• The layer has a thickness of 70 mm copper with an area
of 5500 mm
2
copper and 20% conductivity
Figure 3. Example of NQFP−32 PCB Ground Plane Layout in Top View (Preferred Layout at Top and Bottom)
NQFP−32
ELECTRICAL SPECIFICATION
Recommended Operation Conditions
Operating ranges define the limits for functional
operation and parametric characteristics of the device. Note
that the functionality of the chip outside these operating
ranges is not guaranteed. Operating outside the
recommended operating ranges for extended periods of time
may affect device reliability.
Table 4. OPERATING RANGES
Symbol Parameter Min Max Unit
V
BB
Analog DC supply +6 +30 V
V
DD
Logic supply voltage 4.75 5.25 V
T
J
Junction temperature −40 +172 (Note 5) °C
5. No more than 100 cumulative hours in life time above T
tw
