Reduction technique for power supply noise of analog-digital mixed circuit boards — Adjustment of attached resistor method

In analog-digital mixed circuit boards, noises from the digital side to the analog side through G ND power supply layer is one of the problems. As one of the methods to reduce noise, slot type GND power supply layer is used. It is to divide G ND power supply layer with slot. However, this method has problems. One of the problems is impedance mismatch on the signal line between the analog and digital. And, another problem is increasing the crosstalk between parallel signal line. Therefore, we adjusted to attaching resistor around the circuit board. This Attached Resistor Method is proposal technique as a method reducing radiation noise from power supply layers. As a result evaluation by the simulation, we were able to make sure the effectiveness in reduction noise.