AN7302 - Synergy Microwave Corporation

GUIDELINE FOR AUTOMATED REFLOW SOLDERING PROCESS
FOR DCO, DXO AND DBO SERIES OF VOLTAGE CONTROLLED
OSCILLATORS
Forward
The guidelines provided in this application note comply with JEDC J-STD-020 and describe the basic
surface-mounting assembly requirements for solder reflow of voltage controlled oscillators and
synthesizers manufactured by Synergy Microwave Corporation. Optimum yields are achieved by careful
optimization of the heating profile to allow for package size limitations.
Peak Reflow Temperature
Determining the maximum allowable peak reflow temperature is a process that involves consideration of
the package volume and thickness for both SnPb and Pb-free soldering processes as described in Table I
below:
Table I.
Package peak reflow temperature (Tp)
Volume
Reflow
Process
Thickness
SnPb
>2.5 mm
225oC +0/-5oC
Pb-Free
>2.5 mm
260oC +0/-5oC
<350 mm3
tP
Tp
Critical Zone
TL to TP
Temperature
Ramp-up
TL
tL
Tsmax
Ramp-down
Tsmin
tS
Preheat
25oC
t 25oC to Peak
Time
Figure 1.
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Temperature reflow profile
AN7302 Rev. A 01/13/15
Table II. Reflow profile parameters
Reflow Profile Feature
Average ramp-up rate
(Tsmax to Tp)
Preheat
-Minimum Temperature (TSmin)
-Maximum Temperature (TSmax)
-Time (TSmin to TSmax)
Time maintained above:
-Minimum Temperature (TL)
-Time (tL)
Peak Temperature (Tp)
Time within 5oC of actual peak
temperature (tp)
Ramp-down rate
Time at 25oC to Peak
Temperature
SnPb Eutectic Assembly
Pb-Free Assembly
3oC/second max.
3oC/second max.
100oC
150oC
60 – 120 seconds
150oC
200oC
60 – 180 seconds
183oC
60 – 150 seconds
Per Table I
217oC
60 – 150 seconds
Per Table I
10-30 seconds
20-40 seconds
6oC/second max.
6oC/second max.
6 minutes max.
8 minutes max.
Consideration for maximum reflow temperature limits– One reflow pass
All parts are soldered internally with solder having a reflow temperature melting point of 235 ºC. If the
maximum reflow profile does not exceed 228 ºC, no special cooling precautions are required. In cases
where the application requires the solder profile to exceed 228 ºC (Never to exceed 260 ºC!), care has to
be taken so that the module will not be exposed to any vibration, as the molten solder can shift component
placement. The molten solder must be allowed to solidify with no vibration until the device cools down to
below 220 ºC. This allows for any residual heat trapped in the device to cool below the solder melting
temperature, which is usually hotter inside the device.
For technical assistance contact:
Synergy Microwave Corporation
201 McLean Boulevard
Paterson, NJ 07504
Tel. 973-881-8800
Fax 973-881-8361
Email: [email protected]
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AN7302 Rev. A 01/13/15
- Recommended Solder Reflow profile for Pb-Free Process -
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AN7302 Rev. A 01/13/15