| About This Document  | 
About This Document | 1  | 
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This document provides layout information and guidelines for designing platform or 
This document is intended to be used as a guideline only. Intel recommends that you employ best- known design practices with 
1.1Terminology and Definitions
Table 1.  | Terminology and Definition (Sheet 1 of 2) | 
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  | Definition | |
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  | 31154  | Intel® 31154 133 MHz PCI Bridge  | 
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  | Stripline in a PCB is composed of the  | 
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  | conductor inserted in a dielectric with GND  | 
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  | planes to the top and bottom, as shown in the  | 
  | Stripline  | 
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  | NOTE: An easy way to distinguish stripline  | |
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  | from microstrip is that you need to  | 
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  | strip away layers of the board to view  | 
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  | the trace on stripline.  | 
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  | Microstrip in a PCB is composed of the  | 
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  | Microstrip  | 
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  | conductor on the top layer above the  | 
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  | dielectric with a ground plane below, as  | |
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  | shown in the   | 
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  | Prepreg is material used for the lamination process of manufacturing PCBs. It consists of a  | |||||||
  | Prepreg  | layer of epoxy material that is placed between two cores. This layer melts into epoxy when  | |||||||
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  | heated and forms around adjacent traces. | 
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  | Core | Core material is used for the lamination process of manufacturing PCBs. This material is two-  | |||||||
  | sided laminate with copper on each side. The core is an internal layer that is etched.  | ||||||||
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  | Layer 1: copper  | Printed circuit board: An example PCB  | |
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  | manufacturing process consists of the  | ||
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  | Prepreg  | following steps:  | |
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  | Layer 2: GND  | • A PCB consists of alternating layers of  | |
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  | Core  | core and prepreg stacked.  | |
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  | • The finished PCB is heated and cured.  | ||
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  | Layer 3: VCC  | ||
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  | • The via holes are drilled.  | |||
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  | Prepreg  | ||
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  | Layer 4: copper  | • Plating covers holes and outer surfaces.  | |
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  | • Etching removes unwanted copper.  | 
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  | Example of a   | • The PCB is tinned, coated with solder  | ||||||
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  | mask, and   | ||||||
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Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide  | 7  |