Two Frequently Asked Questions about pcb Design
o-leading.com
o-leading.com
2017-10-25 14:30:29
Can I use the IBIS model of the device to simulate the logic of the device? If not, then how to carry out circuit board and system level simulation?
The IBIS model is a behavioral model and can not be used for functional simulation. Functional simulation, the need to use SPICE model, or other structural level model.
51, in the digital and analog coexistence of the system, there are two kinds of processing methods, one is digital and analog to separate, such as in the formation, digital ground is a separate, analog independent of a single point with copper or FB magnetic Bead connection, and the power is not separated; the other is analog power and digital power supply separately with the FB connection, and is a unified ground. I would like to ask Mr. Lee, these two methods are the same effect?
It should be said that the principle is the same. Because the power supply and ground are equivalent to the high frequency signal.
Distinguish the analog and digital parts of the purpose is to anti-interference, mainly digital circuit on the analog circuit interference. However, segmentation may cause the signal return path to be incomplete, affecting the signal quality of the digital signal, affecting the EMC quality of the system. Therefore, regardless of which plane to split, to see this, the signal return path is increased, the return signal on the normal working signal interference how much. Now there are some mixed design, regardless of power and ground, in the layout, according to the digital part of the analog part of the layout and wiring, to avoid cross-district signal.
The IBIS model is a behavioral model and can not be used for functional simulation. Functional simulation, the need to use SPICE model, or other structural level model.
It should be said that the principle is the same. Because the power supply and ground are equivalent to the high frequency signal.
Distinguish the analog and digital parts of the purpose is to anti-interference, mainly digital circuit on the analog circuit interference. However, segmentation may cause the signal return path to be incomplete, affecting the signal quality of the digital signal, affecting the EMC quality of the system. Therefore, regardless of which plane to split, to see this, the signal return path is increased, the return signal on the normal working signal interference how much. Now there are some mixed design, regardless of power and ground, in the layout, according to the digital part of the analog part of the layout and wiring, to avoid cross-district signal.