How much pressure C3M0075120J can bear

MiaoQ

Hello WOLFSPEED,

I want to put heatsink on top of C3M0075120J, so could you tell me how much pressure TO263-7 package can bear?

Thanks!

AAnders

Hello MiaoQ,

Could you please provide some additional information about the configuration you are designing? Typically heat is extracted out of the TO263 package from the drain tab either through a heatsink soldered onto the PCB around the device, or through an array of vias under the drain pad to a heatsink on the bottom of the board as shown in the figure below.

The attachment of the PCB to the heatsink will depend on the thermal interface material (TIM) used. If the interface uses a compressible material such as a SilPad, clamping force will need to be applied. This clamping force can be applied to the TO263 package itself if desired, but you need to consider the complete system including the PCB and any possible bowing of the PCB that may result. Typically the device package can withstand a much higher force than the solder joints or PCB itself.

If you can provide more details about your design, we can help to further assess the situation.

Thanks,

Adam

MiaoQ

Dear Adam，

Much appreciated for your great support!

The thermal interface material is critical for system design. Can you recommend thermal interface material (TIM)?

AAnders

Hi MiaoQ,

Please see this forum discussion for more specifics on some thermal interface materials:

https://forum.wolfspeed.com/discussion/277/thermal-management-in-smd-components

In addition to the TIM material between the PCB and the heatsink, it is important to have a good via structure to transfer the heat through the PCB. These should be epoxy filled so as to not wick solder away from the joint. Here is a typical via pattern that we suggest.

Thanks,

Adam

MiaoQ

I got it. Thank you very much!

Tangwei

Hi Adam,

I have similar question, how much mechanical pressure or force can the TO-247 body bear.

can you provide maximum value , or if we can infer the value from the recommended mounting torque value? thanks

AAnders

Hello,

The minimum recommended force is 15N to provide good thermal contact. The maximum pressure is 150N/mm^2, so you need to ensure that the contact surface (either the washer for the screw, or the spring clip) is large enough to stay below this limit. I would encourage you to do thermal tests with a range of clamping force to determine a suitable value. Most thermal interface materials reach a plateau in thermal impedance where increasing pressure does not provide any improvement in thermal performance.

Thanks,

Adam

Tangwei

thanks a lot!

Tangwei

Hi Sir，

if maximum pressure of TO-247 is suitable for TO-263 , which also is 150N/mm^2 ？

or this value is not only due to the material but also regarding the body structure, thanks

BGochis

Hello,

The TO-263 package body also has a maximum pressure of 150N/mm^2 but care must be taken to follow SMT soldering best practices to ensure quality solder joints to prevent the force from causing damage at the PCB level

Thanks

Tangwei

thanks a lot！

Tangwei

Hi BGochis,

our customer calculate the maximum force on body with 150N/mm^2 , which is more than 1000kg, they think it is impossible and would damage the structure of body . maximum pressure is generally can meet less than 150N/mm^2 in application, but they want to know the critical force value that would not destroy the body , thanks

BGochis

Tangwei,

The recommended minimum clamping force that is suggested is 15N. The maximum force that should be applied to the package is around 150N. Keeping the force applied to the package below this number will ensure there is no damage to the package body but enough to ensure good thermal contact with a heatsink.

Thanks

Tangwei

Hi BGochis，

thanks for your kindly explanation, besides if the body can endure 15KG at temperature of 150°C ,whether EMC has deformation risk?

BGochis

Hey Tangwei, that is not something that we have tested yet so I cannot say for certain. There are some test plans ongoing that includes similar test conditions and I can provide you those results when I have them

Thanks

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.

Tangwei

Hi TBhatia,

sorry , I reopen this discussion because I need BGochis's maximum pressure of body at high temperature, thanks

BGochis

Hey Tangwei,

We have some testing going on currently that involves this sort of experiment and I hope to have the results in the near future and can share them with you at that time

Thanks

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.

Tangwei

Hi BGOCHIS,

Hope the experiment goes well , do we have any test result for the maximum pressure, can it exceed 300N at 150C temperature? thanks a lot

BGochis

Hey Tangwei,

Based off of our experiments, the maximum pressure applied to the package body is 150N/mm^2 which can be done within the temperature range of the package (which is specified on the part datasheet) which includes 150C. So as long as other system best practices are followed, there should not be any issues with your conditions

Tangwei

Many thanks, so we now can give a 150N/mm^2 pressure guide , but no force value, right?

BGochis

Hello,

A force of 300N is well within the limits of the package

Tangwei

thanks a lot !