PCB News - Pay special attention to the short circuit inside the IC

1. If it is manual soldering, develop a good habit. First, check the PCB board visually before soldering, and use a multimeter to check whether the key circuits (especially the power supply and ground) are short-circuited; secondly, each time a chip is soldered Use a multimeter to check whether the power supply and ground are short-circuited; in addition, do not throw the soldering iron randomly when soldering. If you throw the solder onto the solder feet of the chip (especially surface mount components), it will not be easy to find.

2. Open the PCB diagram on the computer, light up the short-circuited network, see where it is close, it is easy to be connected together. Pay special attention to the short circuit inside the IC.

3. A short circuit is found. Take a board to cut the line (especially suitable for single/double-layer boards), and power on each part of the functional block separately after cutting the line, and remove part of it.

4. Use a short-circuit location analyzer, such as: Singapore PROTEQ CB2000 short-circuit tracker, Hong Kong Lingzhi Technology QT50 short-circuit tracker, British POLAR ToneOhm950 multi-layer board short-circuit detector, etc.

5. If there is a BGA chip, since all the solder joints are covered by the chip and cannot be seen, and it is a multilayer board(above 4 layers), it is good to separate the power supply of each chip during the design, using magnetic beads or 0 ohm resistors Connect, so that when there is a short circuit between the power supply and the ground, the magnetic bead detection is disconnected, and it is easy to locate a certain chip. Because the welding of BGA is very difficult, if it is not automatically welded by the machine, a little carelessness will short-circuit the adjacent power supply and the ground two solder balls.

6. Be careful when soldering small-size surface-mount capacitors, especially power supply filter capacitors (103 or 104), which can easily cause a short circuit between the power supply and the ground. Of course, sometimes with bad luck, the capacitor itself is short-circuited, so it is a good idea to test the capacitor before welding.

The above is the introduction of PCB short circuit inspection methods. Ipcb is also provided to PCB manufacturers and PCB manufacturing technology.