First, the general rules and requirements
1 Press unified asked to select the drawing format , frame format , the schematic graphic symbols , text symbols.
2 electrical work should be based on the principle of the product, the various components from right to left , top to bottom in a row or columns .
3 When drawing arrangement , the power in the lower left part of the general arrangement , the input to the right , the left output .
4 movable figure element ( such as relays ) the operating state , in breaking the principle working position without electricity .
5 all the chip's power and ground pins fully utilized .
Second, consider the signal integrity and electromagnetic compatibility
1 input and output signals corresponding filter to add / absorption device ; when necessary to absorb transient voltage applied silicon diode or varistor SVC
(2) In the high-frequency signal output series resistor.
3 decoupling capacitors high frequency region to choose low ESR electrolytic or tantalum capacitors
4 Under the conditions required to meet the ripple choose a smaller capacitance value of the capacitor when the decoupling capacitance value is determined to improve its resonant frequency
5 will be added for each chip 's power decoupling capacitors, the same chip power modules were added to the decoupling capacitors ; such as high-frequency power supply shall be at the end by adding beads / inductors .
Third, the corresponding PCB after the completion of the schematic and PCB
PCB distribution parameters for sensitive components ( such as filtering capacitors, clock damping resistors, high frequency filtering beads / inductors, etc. ) to check the nominal value optimization , subject to change and update the schematic BOM, rearrangement by the PCB Layout label information updated schematics and BOM, BOM generated document, the schedule does not allow non- model components of the device appears. The same type of device does not allow the use of different representation methods, such as using only 4.7K 4.7K resistor , said , does not allow the use of 4K7 and other representation.
