Modified LQFP pattern

Created Tuesday 18 October 2022

Download link:
.\Modified LQFP land pattern for solder bridging prevention.pdf

Drawbacks:

1. Each second pin solder joint is hidden; no visual inspection inspection is possible
2. Some pins may left unsoldered, especially if IC and/or soldering paste are stored for a long period of time (see image below)

Two pins are not soldered properly: solder not soaked under the pin and formed a solder ball instead.
LQFP-100, package opened for >1 week, 50% humidity
Solder paste MECHANIC XGZ40 Sn63Pb37 syringe stored at 25-35°C for 6 month

Possible solutions:

1. Treat LQFP pads with flux pen before applying paste, so solder is soaked under the pin
2. Soak LQFP chip in liquid flux before placement