DIY fan debugging welding precautions

okhxyyo

DIY fan debugging welding precautions [Copy link]

Author: @Blue Angel

Top view

Bottom View

For those who don't have a heat gun, the power management is difficult to weld the negative pole, and the fan will not work if the welding is bad. Here is a recommended welding method

Use a soldering iron to apply a layer of tin to the negative pad, and also apply a layer of tin to the corresponding pad on the PCB. Turn the IC over with tweezers and place it on the PCB, then place the soldering iron on the four pins on one side. The soldering iron temperature is adjusted to 400℃. The solder on the negative pad will melt in about 5S. At this time, use tweezers to press the plastic package of the IC to make it close to the circuit board, ensuring that all eight pins can be accurately attached to the corresponding pads (the pins must not float). Release the soldering iron. Adjust the temperature to 350℃ and solder the remaining pins. The high temperature time should not be too long, otherwise there is a risk of damaging the IC.

After the whole soldering is completed, wait for the board to cool down to room temperature and plug in the fan and battery (pay attention to polarity). The IC may be overpowered and under thermal protection.

Debugging: Before installing the battery and fan, check that there are no conductors under the board to avoid short circuits and other faults.

chunyang

For the chip with a large pad on the bottom in the original post, the simple manual soldering method is actually very simple. You only need to make a package yourself when designing the PCB, use two double-sided square pads without holes on the bottom, and then stack 1 or 4 through holes on the square pads. Note that it cannot be a through hole, so as not to be covered by solder mask or confuse the PCB factory. Also, note that the diameter of the through hole must be large enough to basically cover most of the square pad at the bottom of the chip.

When soldering, first solder the chip as usual, then turn over the PCB and fill the bottom through-hole pad with tin, and fill the through-hole with solder. This design of the PCB is mainly for manual soldering. To be compatible with manual and reflow soldering, it is necessary to appropriately reduce the through-hole diameter and use multiple through-holes to prevent the solder paste from leaking or failing to fill the through-hole, which can easily lead to soldering quality problems. If only manual soldering is considered, only one large through-hole needs to be set, and the soldering operation is the simplest and most reliable.

I use this method when designing PCBs for such chips, and this design is also more beneficial for heat dissipation.

okhxyyo

chunyang posted on 2022-7-5 15:09 For the chip with a large pad on the bottom in the original post, the simple manual soldering method is actually very simple. You only need to make a package when designing the PCB. The bottom...

Good idea

tagetage

It is OK to not cover the large aperture pad with oil.

se7ens

Yes, it is also possible to open a large hole on the pad

秦天qintian0303

chunyang posted on 2022-7-5 15:09 For the chip with a large pad on the bottom in the original post, the simple manual soldering method is actually very simple. You only need to make a package when designing the PCB. The bottom...

This method is quite good, but the bottom pad must be large enough

chunyang

Qintianqintian0303 posted on 2022-7-7 12:03 This method is quite good, but the bottom pad must be large enough

The above method is originally for chips with large bottom pads...