Shenzhen professional pcb design company here gives you a little bit of PCB wiring principles, usually the following rules we have to do
1.1 The PCB is pre-divided into digital, analog, and DAA (data access arrangement) signal routing areas.
1.2 Digital and analog components and corresponding traces should be separated as much as possible and placed in their respective wiring areas.
1.3 High-speed digital signal traces should be as short as possible.
1.4 Sensitive analog signal traces should be as short as possible.
1.5 Reasonably distribute power and ground.
1.6 DGND, AGND, and ground.
1.7 Power and critical signal traces use wide lines.
1.8 The digital circuit is placed near the parallel bus/serial DTE interface, and the DAA circuit is placed near the telephone line interface.
2. Component placement
2.1 Shenzhen professional pcb design company in the system circuit schematic:
a) dividing digital, analog, DAA circuits and their associated circuits;
b) dividing digital, analog, and mixed digital/analog components in each circuit;
c) Pay attention to the positioning of the power and signal pins of each IC chip.
2.2 Preliminary division of the digital, analog, DAA circuit on the PCB board (general ratio 2/1/1), digital and analog components and their corresponding traces as far as possible and limited in their respective wiring areas.
Note: When the DAA circuit accounts for a large proportion, there will be more control/status signal traces crossing its wiring area, which can be adjusted according to local rules, such as component spacing, high voltage suppression, current limit, etc. Www.pcbdown.cn
2.3 After the initial division, the components are placed from the Connector and Jack:
a) the location of the plugin around the Connector and Jack;
b) leaving room for power and ground traces around the components;
c) Leave the location of the corresponding plugin around the Socket.
2.4 First place hybrid components (such as Modem devices, A/D, D/A converter chips, etc.):
a) Determine the direction in which the components are placed, and try to make the digital signal and analog signal pins face the respective wiring areas;
b) Place the components at the junction of the digital and analog signal routing areas.
2.5 Place all analog devices:
a) placing analog circuit components, including DAA circuits;
b) the analog devices are close to each other and placed on the PCB with one side of the TXA1, TXA2, RIN, VC, VREF signal traces;
c) Avoid placing high-noise components around the TXA1, TXA2, RIN, VC, and VREF signal traces;
d) For serial DTE modules, DTE EIA/TIA-232-E
The receiver/driver of the series interface signals is placed as close as possible to the connector and away from the high-frequency clock signal traces to reduce/avoid added noise suppression devices such as chokes and capacitors on each line.
2.6 Shenzhen professional pcb design company placed digital components and decoupling capacitors:
a) Digital components are placed centrally to reduce the length of the traces;
b) Place a 0.1uF decoupling capacitor between the IC's power/ground, and connect the traces as short as possible to reduce EMI;
c) For parallel bus modules, components are close
The edge of the connector is placed to conform to the application bus interface standard, such as the ISA bus trace length is limited to 2.5in;
d) for the serial DTE module, the interface circuit is close to the Connector;
e) The crystal oscillator circuit is as close as possible to its drive device.
2.7 Ground wire in each area, usually connected by one or more points with 0 Ohm resistor or bead.
Well, the above is some basic principles of the small professional editor of Shenzhen professional pcb design company, I hope to be useful to everyone.