PCIE布线规范.pdf

MCS9901 PCB Layout PCB Layout GuideLines Guidelines 1.Introduction As system operation speeds are increasing, PCB layout is becoming increasingly complex. A successful high-speed layout / PCB need to integrate the IC’s and other peripherals / components effectively into a single design. MCS9901 has PCIe, Serial, Parallel, ISA USB interfaces and utilize fast I/O pins with edge rates that are less than a hundred picoseconds. As Fast edge rates can contribute to noise generation, signal reflection, cross-talk and ground bounce; System designers must be careful in handling these issues during PCB layout design. This document provides generic layout guidelines for MCS9901 based products. PCIe to 4 Serial evaluation board design used as an example to detail the guidelines below. 2. PCB Overview 2.1.1. PCB Details Figure 1a is the Top side of the MCS9901 4Serial Board. Most of the components are placed on the Top side of the PCB. Supply decoupling capacitors used on the bottom side to arrive at small form factor. Customers wishing to have components only of top side for process cost reasons can do so, with appropriate layout. Figure 1a - Top Side View of MCS9901-4S-EVB Rev1.1 Preliminary - 1 - 26th Nov 2007 MCS9901 PCB Layout PCB Layout GuideLines Guidelines Figure 1b Top Side View - Component Placement MCS9901-4S-EVB 2.2 Components Placement A. MCS9901 ASIC B. 12 MHz CRYSTAL C. SERIAL PORTS Rev1.1 Preliminary - 2 - 26th Nov 2007 MCS9901 PCB Layout PCB Layout GuideLines