1. Before soldering, apply flux on the padand treat it with a soldering iron to avoid poor tin plating or oxidation ofthe pad, resulting in poor soldering, and the chip generally does not need tobe processed.

2. Carefully place the PQFP chip on the PCBwith tweezers, taking care not to damage the pins. Align it with the pads,making sure the chip is placed in the correct orientation. Adjust thetemperature of the soldering iron to more than 300 degrees Celsius, dip a smallamount of solder on the tip of the soldering iron, press down on the chip thathas been aligned with the tool, and add a small amount of flux to the pins atthe two opposite corners. Hold the chip down and solder the pins on twoopposite corners so that the chip is fixed and cannot be moved. Recheck thealignment of the chip after soldering the diagonal corners. Adjust if necessaryor remove and realign on the PCB.

3. When starting to solder all pins, addsolder to the tip of the soldering iron and apply flux to all pins to keep the pinswet. Touch the end of each pin of the chip with the tip of the soldering ironuntil you see solder flowing into the pin. When soldering, keep the tip of thesoldering iron parallel to the pins to be soldered to prevent overlapping dueto excess solder.

4. After soldering all the pins, wet allthe pins with flux to clean the solder. Absorb excess solder where needed toeliminate any shorts and laps. Finally, use tweezers to check whether there isany virtual soldering. After the inspection is completed, remove the flux fromthe circuit board, dip a stiff brush in alcohol and wipe it carefully along thedirection of the pins until the flux disappears.