Tinning Leads

[britain_taulbee]

I'm working with P/N MPXM2202A which is a gold-leaded component, and IPC states that I should be pre-tinning this component before board installation in order to avoid gold embrittlement.  According to your soldering recommendations document (AN3150), the suggested max temp for this part is 482 F (250 C), but my solder pot is only certified for 490 F. 

Is the max temp spec referring to a max temp of the component body, or does it refer to the leads as well?  Or to ask the question more basically, am I ok to dip the leads in my solder pot to tin them?  If not, how would you recommend doing so?

Thank you.

[TomasVaverka]

Hi Britain,

I have asked both the packaging engineer and product engineer to comment on this...

The melting point of plastic package (such as SSOP, SOP and Mpak) is 285 C so theoretically it is possible to dip the leads. Point of caution, the legacy pressure sensors are not qualified for Pb free reflow process (peak temp around 260 C) due to high thermal expansion of the gel. Thus, the suggested max temp for this part is 250 C. At 254.4 C (or 490 F), you will run the risk of going over the temp the gel can handle so in this case, NXP can’t guarantee the performance.  The max temp spec refers to the sensor as a whole including the leads.

We can only suggest to try and then test to your final performance requirements.

Plating specification is:

Ni : Min 0.508 um

Pd : Min 0.0254 um

Au : Min 0.0254 um

Best regards,

Tomas

[britain_taulbee]

I would also like to know the plating thickness of the gold leads.  The plating indicator for this part is "e4" which defines it as gold, but I cannot find the thickness.