SOT-363 PCB Footprint
A recommended PCB pad layout
for the miniature SOT-363 (SC-70)
package used by the MGA-82563 is
shown in Figure 21 (dimensions
are in inches). This layout pro-
vides ample allowance for pack-
age placement by automated
assembly equipment without
adding parasitics that could
impair the high frequency RF
performance of the MGA-82563.
The layout is shown with a
nominal SOT-363 package foot-
print superimposed on the PCB
pads.
0.026
material, process, and equipment
factors, including: method of
heating (e.g., IR or vapor phase
reflow, wave soldering, etc.)
circuit board material, conductor
thickness and pattern, type of
solder alloy, and the thermal
conductivity and thermal mass of
components. Components with a
low mass, such as the SOT-363
package, will reach solder reflow
temperatures faster than those
with a greater mass.
The MGA-82563 is has been
qualified to the time-temperature
profile shown in Figure 22. This
profile is representative of an IR
reflow type of surface mount
assembly process.
After ramping up from room
temperature, the circuit board
with components attached to it
(held in place with solder paste)
passes through one or more
preheat zones. The preheat zones
increase the temperature of the
board and components to prevent
thermal shock and begin evaporat-
ing solvents from the solder paste.
The reflow zone briefly elevates
the temperature sufficiently to
produce a reflow of the solder.
The rates of change of tempera-
ture for the ramp-up and cool-
down zones are chosen to be low
enough to not cause deformation
of the board or damage to compo-
nents due to thermal shock. The
maximum temperature in the
reflow zone (T
MAX
) should not
exceed 235
°C.
These parameters are typical for a
surface mount assembly process
for the MGA-82563. As a general
guideline, the circuit board and
components should be exposed
only to the minimum tempera-
tures and times necessary to
achieve a uniform reflow of
solder.
Electrostatic Sensitivity
0.075
0.035
0.016
Figure21. PCBPadLayout
(dimensionsininches).
SMT Assembly
Reliable assembly of surface
mount components is a complex
process that involves many
250
T
MAX
200
TEMPERATURE (°C)
150
Reflow
Zone
100
Preheat
Zone
50
0
0
60
120
180
240
300
TIME (seconds)
Cool Down
Zone
GaAs MMICs are
electrostatic discharge
(ESD) sensitive
devices. Although the
MGA-82563 is robust in design,
permanent damage may occur to
these devices if they are subjected
to high energy electrostatic
discharges. Electrostatic charges
as high as several thousand volts
(which readily accumulate on the
human body and on test equip-
ment) can discharge without
detection and may result in
degradation in performance or
failure. The MGA-82563 is a ESD
Class 1 device. Therefore, proper
ESD precautions are recom-
mended when handling, inspect-
ing, and assembling these devices
to avoid damage.
Figure 22. Surface Mount Assembly Profile.
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AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
