PCB design uniform, PCB Assembly through the digital circuits and simulated circuit partition and the right signal wiring, usually can solve some problems more difficult route, but also will not have to split because of some potential trouble caused. In this case, components of the layout and design district on the merits of a key decision. If the layout is reasonable, PCBA manufacturer digital ground currents will be limited to the number of parts of the circuit board, does not interfere with the simulated signal.
For such wiring must be careful to check and check wiring to ensure one hundred percent compliance with the rules. Otherwise, improper alignment of a signal line will be completely destroyed in an otherwise very good board.
In the A / D converter simulation and pcb assembly China digital ground pins are connected together, most of the A / D converter manufacturers recommend :AGND and DGND pins through the shortest lead connected to the ground with a low-impedance (Note:because most of A / D converter chip and digital simulations have not connected together, to be achieved pcba manufacturer by an external simulation and digital ground pin connection), any external impedance DGND connection will be through the parasitic capacitance more internal digital noise coupled to the IC circuit simulation.
According to this proposal, you need to A / D converter AGND and DGND pins are connected to the simulation of the ground, but this method will produce the digital signal, such as decoupling capacitors to ground should be received or digital simulation to the problem.