https://devzone.nordicsemi.com/f/nordic-q-a/20155/ultrasonic-bonding-technology-51822i have a nrf51822 mcu device, when it ok, i use Ultrasonic bonding technology to Assembled box,and today,many device crashed,is it related to ultrasonic?en-USTelligent Community 13Fri, 03 Mar 2017 15:38:49 GMThttps://devzone.nordicsemi.com/thread/78488?ContentTypeID=1Fri, 03 Mar 2017 15:38:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:4fe82a47-b643-4a40-a768-73bc4ead9006Sigurd<p>Hi,</p> <p>The nRF5x SoC is designed for reflow soldering, and I would recommend using reflow soldering over ultrasonic welding.</p> <p>We have some customers that have used ultrasonic welding, and as long as the chip is not exposed to unnecessary mechanical stress during bonding, it should be ok. But, you should also ask the PCB manufacturer about this. Note that some manufacturers does not recommend ultrasonic welding because it can damage the crystal.</p><div style="clear:both;"></div>