Precautions for IC Substitution in PCB Circuit Design
1. Correctly connect the number sequence of the integrated PCB circuit pins.
2. In order to adapt to the characteristics of the replaced IC, the components of the peripheral PCB circuit connected to it should be changed accordingly.
3. The power supply voltage must be in line with the replaced work C. If the power supply voltage in the original PCB circuit is high, you should find a way to reduce the voltage. The voltage is low, it needs to see whether the replacement IC can work normally.
4. After the replacement, it is necessary to measure the quiescent working current of the IC. If the current is far beyond the normal value, it means that the PCB circuit is likely to generate self-excitation. At this time, decoupling and adjustment must be carried out. If the gain is different from the original one, you can adjust the resistance of the feedback resistor.
5. After the replacement, the input and output impedance of the IC need to match the original PCB circuit, and its drive capability should also be checked
6. When making changes, you need to make full use of the pin holes and leads on the original PCB circuit board. The external leads are required to be neat and prevent front and rear crossing, which helps to check and avoid PCB circuit self-excitation, especially to avoid high-frequency self-excitation.
7. Before turning on the power, it is recommended to connect a DC ammeter in series in the power supply Vcc loop, and the resistance value of the step-down resistor is from large to small, and then observe whether the change of the total current of the integrated PCB circuit is normal.
2. In order to adapt to the characteristics of the replaced IC, the components of the peripheral PCB circuit connected to it should be changed accordingly.
3. The power supply voltage must be in line with the replaced work C. If the power supply voltage in the original PCB circuit is high, you should find a way to reduce the voltage. The voltage is low, it needs to see whether the replacement IC can work normally.
4. After the replacement, it is necessary to measure the quiescent working current of the IC. If the current is far beyond the normal value, it means that the PCB circuit is likely to generate self-excitation. At this time, decoupling and adjustment must be carried out. If the gain is different from the original one, you can adjust the resistance of the feedback resistor.
5. After the replacement, the input and output impedance of the IC need to match the original PCB circuit, and its drive capability should also be checked
6. When making changes, you need to make full use of the pin holes and leads on the original PCB circuit board. The external leads are required to be neat and prevent front and rear crossing, which helps to check and avoid PCB circuit self-excitation, especially to avoid high-frequency self-excitation.
7. Before turning on the power, it is recommended to connect a DC ammeter in series in the power supply Vcc loop, and the resistance value of the step-down resistor is from large to small, and then observe whether the change of the total current of the integrated PCB circuit is normal.