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www.fairchildsemi.com
RMPA0965 Rev. F
RMPA0965 Cellular CDMA, CDMA2000-1X and WCDMA PowerEdge™ Power Amplifier Module
Application Information
CAUTION: THIS IS AN ESD SENSITIVE DEVICE
Precautions to Avoid Permanent Device Damage:
•Cleanliness: Observe proper handling procedures to ensure
clean devices and PCBs. Devices should remain in their
original packaging until component placement to ensure no
contamination or damage to RF, DC & ground contact areas.
•Device Cleaning: Standard board cleaning techniques should
not present device problems provided that the boards are
properly dried to remove solvents or water residues.
•Static Sensitivity: Follow ESD precautions to protect against
ESD damage:
–A properly grounded static-dissipative surface on which to
place devices.
–Static-dissipative floor or mat.
–A properly grounded conductive wrist strap for each person
to wear while handling devices.
•General Handling: Handle the package on the top with a
vacuum collet or along the edges with a sharp pair of bent
tweezers. Avoiding damaging the RF, DC, & ground contacts
on the package bottom. Do not apply excessive pressure to
the top of the lid.
•Device Storage: Devices are supplied in heat-sealed,
moisture-barrier bags. In this condition, devices are protected
and require no special storage conditions. Once the sealed
bag has been opened, devices should be stored in a dry
nitrogen environment.
Device RF:
Fairchild RF recommends the following procedures prior to
assembly.
•Dry-bake devices at 125°C for 24 hours minimum. Note: The
shipping trays cannot withstand 125°C baking temperature.
•Assemble the dry-baked devices within 7 days of removal
from the oven.
•During the 7-day period, the devices must be stored in an
environment of less than 60% relative humidity and a
maximum temperature of 30°C
• If the 7-day period or the environmental conditions have been
exceeded, then the dry-bake procedure must be repeated.
Solder Materials & Temperature Profile:
Reflow soldering is
the preferred method of SMT attachment. Hand soldering is not
recommended.
•Reflow Profile
–Ramp-up: During this stage the solvents are evaporated
from the solder paste. Care should be taken to prevent
rapid oxidation (or paste slump) and solder bursts caused
by violent solvent out-gassing. A typical heating rate is 1-
2°C/sec.
–Pre-heat/soak: The soak temperature stage serves two
purposes; the flux is activated and the board and devices
achieve a uniform temperature. The recommended soak
condition is: 120-150 seconds at 150°C.
–Reflow Zone: If the temperature is too high, then devices
may be damaged by mechanical stress due to thermal
mismatch or there may be problems due to excessive
solder oxidation. Excessive time at temperature can
enhance the formation of inter-metallic compounds at the
lead/board interface and may lead to early mechanical
failure of the joint. Reflow must occur prior to the flux being
completely driven off. The duration of peak reflow
temperature should not exceed 10 seconds. Maximum
soldering temperatures should be in the range 215-220°C,
with a maximum limit of 225°C.
–Cooling Zone: Steep thermal gradients may give rise to
excessive thermal shock. However, rapid cooling promotes
a finer grain structure and a more crack-resistant solder
joint. The illustration below indicates the recommended
soldering profile.
Solder Joint Characteristics:
Proper operation of this device depends on a reliable void-free
attachment of the heatsink to the PWB. The solder joint should
be 95% void-free and be a consistent thickness.
Rework Considerations:
Rework of a device attached to a board is limited to reflow of the
solder with a heat gun. The device should not be subjected to
more than 225°C and reflow solder in the molten state for more
than 5 seconds. No more than 2 rework operations should be
performed.
Figure 1. Recommended Solder Reflow Profile
0
20
40
60
80
100
120
140
DEG (°C)
TIME (SEC)
10 SEC
183°C
1°C/SEC 1°C/SECSOAK AT 150°C
FOR 60 SEC
45 SEC (MAX)
ABOVE 183°C
160
180
200
220
240
060120 180 240 300
