First, the transistor soldering is generally performed after the other components are soldered. The soldering time of each tube should not exceed 10 s. In order to avoid scalding the tube during PCB soldering, should clamp the leads with tweezers to dissipate heat.How to mount the integrated circuit board? What are the matters of concern, the following is shared by FASTPCBA:
(1) Characteristics of integrated circuits
1) MOS circuit: In the manufacturing process of MOS type field effect transistor, the insulating layer is very thin, the insulating gate and the substrate are easy to induce electric charges, and the induced electric charge generates a high voltage on the insulating layer, causing the tube to break down.
2) Bipolar integrated circuit: the internal integration is high, the pipe isolation layer is very thin, and the overheating is easily damaged.
(2) PCB installation welding method
1) Solder the integrated circuit directly to the printed circuit board.
2) Solder the special IC socket to the printed circuit board and insert the integrated circuit into the socket.
(3) Welding precautions
1) For an integrated circuit in which the lead is gold-plated silver, simply wipe the lead with alcohol.
2) For CMOS circuits that short-circuit each lead in advance, the short-circuit line cannot be cut off before soldering, and should be cut it off after soldering.
3) The staff should wear the anti-static wristband on the anti-static workbench, and the workbench should be clean and tidy.
4) When holding an integrated circuit, the outer package of the integrated circuit should be held and the leads should not be touched.
5) When soldering, 20W internal heat soldering iron should be used, and the soldering iron must be grounded reliably.s
6) When welding, the welding time of each lead should not exceed 4s, and the continuous welding time should not exceed 10s.
7) To use a low melting point flux, the melting point of the flux should not exceed 150 °C.
8) For MOS tubes, the S pole should be installed first, and then the G pole the last D pole should be welded.
9) When installing the heat sink, first wipe the mounting surface with alcohol, then apply a layer of silica gel, put it flat and install it with tight screw.
10) When the integrated circuit is directly soldered to the circuit board, the bursting sequence is: ground end → output end → power end → input end
The above is the Shared by PCB assembly factory. For more information, please visit www.medicalpcba.com