MPR121 thermal reflow profile

[jesseenjaian]

I've assembled a couple of packages soaking at 180 C for one minute and reflowing at 249 C for about twenty or thirty seconds using 63/37 solder (not paste) that I tinned on the pads with a soldering iron. I calibrated the temperature with a thermocoupled thermometer, so I'm confident the applied heat is about that; I'm using a head that's about the size of the MPR121 and soaking the entire chip instead of going side-by-side. Does this sound safe for the MPR121, or am I risking damaging it?

Thanks!

Jesse Enjaian

[reyes · Accepted solution]

Hi Jesse Enjaian,

The Peak Package Body Temperature (PPT) for the MPR121 is 260 °C, but the maximum time at this peak temperature is 40 seconds. So yes is a risk that you are damaging the device.

You can find this information in the MPR121 Part Details.

Have a great day,
Jose Reyes

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[jesseenjaian]

Hi Jose,

Thanks for your help. I was looking in the data sheet and reference manual, but didn't see it there.

For future reference, that was an incredibly unnecessary temperature. Using eutectic solder, I soaked at 150 C for one minute then reflowed at 189 C for twenty seconds stepping there at 2-3 C/sec. I was able to initialize and use the chip over I2C doing this.

Thanks again.

Best,

Jesse