请问LPC1752的回流焊曲线是怎么样的?如果芯片损坏的话能否用烙铁进行更换?烙铁的温度和时间要控制在多少?

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请问LPC1752的回流焊曲线是怎么样的?如果芯片损坏的话能否用烙铁进行更换?烙铁的温度和时间要控制在多少?

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chenp
Contributor I

如题:请问LPC1752的回流焊曲线是怎么样的?如果芯片损坏的话能否用烙铁或热风枪进行更换?烙铁/热风枪的温度和时间要控制在多少?

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soledad
NXP Employee
NXP Employee

Hi,

In order to remove a semiconductor package from the board, it must be heated; if possible, this must be done as locally as possible to avoid heating the surrounding board and components. Packages with leads at a relatively large pitch may first be removed from the board by cutting the leads, after which only the leads must be de-soldered. This can be done with a soldering iron.

Semiconductor packages without leads must be heated entirely for removal. Heat can be supplied using a hot air gun, a soldering iron, or focused infrared energy, depending on the package type and availability. If necessary, the bottom of the board can also be heated. The temperature to which the package solder joints should be heated depends on the solder that was originally used, and it is best to keep the temperature as low as possible, just above the melting point of the solder alloy used.

As soon as the solder has melted, the semiconductor package is lifted from the board using a vacuum wand or tweezers; note that package removal should not be initiated until the solder has melted entirely.

Re-use of removed semiconductor packages is not recommended.

I suggest to check the following application note, I hope this helps!

https://www.nxp.com/docs/en/application-note/AN10365.pdf 
Have a great day,
Sol

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chenp
Contributor I

感谢您的会回复。因为焊接的时候使用的是无铅锡丝,所以如果使用烙铁的话焊接温度要求是360℃~380℃,2到3秒的时间,这样焊锡才会融化。若是热风枪拆卸的温度是380℃要求。不知道380℃的温度是否会对LPC1752芯片造成损害?

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soledad
NXP Employee
NXP Employee

Sorry for my delay, please check the AN10365 page 20.

" For reflow soldering with SnPb solder, the peak temperature should be higher than 215°C; when soldering with SAC, the peak temperature should be higher than 235°C, but should not exceed a temperature of 260°C. Note that this usually implies a smaller process window for Pb-free soldering, thus requiring tighter process control."


Have a great day,
Sol

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