User's Manual

PW2050 Embedded Device Server Integration Guide 27
General guidelines are as follows:
The solder composition typically sets the peak temperatures of the profile. Recommend lead
free solder pastes SAC305: Type 4, water soluble or no clean are acceptable.
Reflow equipment needed at least nine heater zones. Recommend forced air type reflow oven
with nitrogen.
It is recommended that the peak temperature at the solder joint be within 235°C ~ 245°C and
the maximum component temperature should not exceed 245°C.
It is recommended that time above 217°C for the solder joints is between 40-90 seconds, and
with a minimum of 40 seconds.
Excessive ramp/cooling rates >3°C per second should be avoided.
To develop the reflow profile, it is recommended that the user place thermocouples at various
locations on the assembly to confirm that all locations meet the profile requirements. The
critical locations are the solder joints of SiP Module.
When developing the reflow profile, it is recommended that the actual fully loaded assembly be
used to make sure that the total thermal mass is accounted for.
Figure 錯誤! 使用 [常用] 索引標籤將 Heading 1 套用到您想要在此處顯示的文字。-3 Recommended
Reflow Profile
(1) Solder paste alloy: SAC305(Sn96.5/Ag3.0/Cu0.5)(Lead free solder paste is recommended.)
(2) A-B. Temperature (pre-heat): 150~200°C; soak time: 60~120 seconds
(3) C. Peak temperature: 245°C
(4) D. Time above 217°C: 40~90 seconds
(5) Suggestion: Optimal cooling rate is 1°C per second from peak to 217°C
(6) Nine heater zones at least for reflow equipment.
(7) Nitrogen usage is recommended and the oxygen concentration is controlled less than 1500
parts per million.
Note: Need to inspect solder joint by X-ray post reflow.