Where ground design requires attention (1)
In ground wire design, the following items should be noted:
Correct selection of single point earthing and multipoint earthing
In low frequency circuits, the operating frequency of the signal is less than 1MHz, and its wiring and inductance between the devices are less affected, and the circulation caused by the grounding circuit has a greater impact on interference, so it should adopt one point grounding. When the signal operating frequency is greater than 10MHz, the ground impedance becomes very large. At this point, the ground impedance should be reduced as far as possible, and the ground multipoint grounding should be adopted. When the working frequency is between 1 and 10MHz, if one point grounding is adopted, the ground wire length shall not exceed 1/20 of the wavelength, or multipoint grounding method shall be adopted.
The circuit board (pcb board Printed company china ) is high speed logic circuit, and linear circuits, so they should try to separate them, and do not ground phase, ground wire and connected to the power supply end respectively. The grounding area of the linear circuit should be increased as much as possible.