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www.fairchildsemi.com

RMPA0967 Rev. E

Application Information

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 Usage: Fairchild recommends the following proce-

dures 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.

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/SEC

SOAK AT 150

°C

FOR 60 SEC

45 SEC (MAX)

ABOVE 183

°C

160

180

200

220

240

0

60

120

180

240

300