The mechanical stress over Top-side-cooling MOSFET

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jiaoleiming
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First reply posted First question asked Welcome!

Hi, I notice that IFX released a series of mosfets with top-side-cooling package, such as TOLT, DDPAK and QDPAK. Since the top surface should be attached on the heatsink or cool plate, I wanna know how much stress(PSI unit) the package could endure and where to find the figures? Any application note is available on the website? thanks 

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Jingwei
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您好,

针对第一个问题,40kg已经使得封装底部挨着PCB了,所以没有在此基础上继续加力。不代表封装只能承受40Kg。

针对第二个问题,之前上传的文件是针对DDPAK和QDPAK,对于TOLT请参考新的附件的page12。

额外的补充:

请注意,装配时的实际应用力应远远小于封装的最大承受力。优化的下降力应考虑到以下因素:

  1. PCB bending
  2. TIM compressed distance (thickness)
  3. Solder joint reliability
  4. Package standoff distance vs down force (related to TIM thickness)
  5. Others

1. PCB bending

Jingwei_0-1654760080656.png

2. TIM compressed distance vs Rth

Jingwei_1-1654760107439.png

3. Solder joint reliability

Jingwei_2-1654760136877.png

4. Package standoff distance vs down force

Jingwei_3-1654760162405.png

 

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Jingwei
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250 sign-ins 10 likes given 100 solutions authored

您好,

感谢使用Infineon Community。

这里有两个对您很有用的AN可以参考一下。如果您关于这个话题还有其他问题,请继续联系我。

https://www.infineon.com/dgdl/Infineon-ApplicationNote_Package_DoubleDPAK_DDPAK-AN-v01_00-EN.pdf?fil...

https://www.infineon.com/dgdl/Infineon-Package_top_side_cooled_package_for_high_voltage_application-...

Best Regards,

Steven

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Hi Steven, 在第一个文档的page28-29描述了DDPAK的极限耐压测试。这里有两点疑问:

(1) page28提到极限压力是2500N,而Figure37的纵轴上限只到40kg(即392N),两者似乎对不上

(2) Figure37底部描述了DDPAK能通过测试,是因为海鸥脚像弹簧一样可以吸收机械应力。然而,我认为该解释仅适用于positive stand-off(如DDPAK, QDPAK),对于negative stand-off(如TOLT),是body在直接承受机械应力,Figure37的实验结果应该不适用于TOLT。而且,对于QDPAK,在0.12mm的stand-off完全吸收形变后,剩下的应力仍然是body在承受。QDPAK面积比DDPAK大很多,Figure37的数据还能沿用在QDPAK吗? 如果不能,那QDPAK和TOLT的数据有没有?

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lock attach
Attachments are accessible only for community members.
Jingwei
Moderator
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Moderator
250 sign-ins 10 likes given 100 solutions authored

您好,

针对第一个问题,40kg已经使得封装底部挨着PCB了,所以没有在此基础上继续加力。不代表封装只能承受40Kg。

针对第二个问题,之前上传的文件是针对DDPAK和QDPAK,对于TOLT请参考新的附件的page12。

额外的补充:

请注意,装配时的实际应用力应远远小于封装的最大承受力。优化的下降力应考虑到以下因素:

  1. PCB bending
  2. TIM compressed distance (thickness)
  3. Solder joint reliability
  4. Package standoff distance vs down force (related to TIM thickness)
  5. Others

1. PCB bending

Jingwei_0-1654760080656.png

2. TIM compressed distance vs Rth

Jingwei_1-1654760107439.png

3. Solder joint reliability

Jingwei_2-1654760136877.png

4. Package standoff distance vs down force

Jingwei_3-1654760162405.png

 

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