Class21_InterconnectI

Class21_InterconnectI - I nte rconne I class 21 ct Pre...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
  Interconnect I – class 21 Prerequisite reading - Chapter 4
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Interconnect: Adv 2 Outline Transmission line losses DC losses in the conductor Frequency dependent conductor losses Frequency dependent dielectric losses Effect of surface roughness Differential line losses Incorporating frequency domain parameters into time domain waveforms Measuring Losses Variations in the dielectric constant
Background image of page 2
3 Interconnect: Adv 3 Focus This chapter focuses on subtle high speed transmission characteristics that have been ignored in most designs in the past These effects become critical in modern designs Older BKM assumptions break down Become more critical as speeds increase As speeds increase, new effects that did not matter become significant This increases the number of variables that must be comprehended Many of these new effects are very difficult to understand This chapter will outline several of the most prominent non-ideal transmission lines issues critical to modern design
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Interconnect: Adv 4 Key Topics: DC resistive losses in the conductor Frequency dependent resistive losses in the conductor Frequency dependent dielectric resistive losses Effect of surface roughness Differential line resistive losses Transmission Line Losses
Background image of page 4
5 Interconnect: Adv 5 Transmission Line Losses (cont’d) These losses can be separated into two categories Metal losses Normal metals are not infinitely conductive Dielectric losses Classic model are derived from the alignment of Electric dipoles in the dielectric with the applied field Dipoles will tend oscillate with the applied time varying field – this takes energy Why do we care about losses? Losses degrade the signal amplitude, causing severe problems for long buses Losses degrade the signal edge rates, causing significant timing push- outs Losses will ultimately become a primary speed limiter of our current technology
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Interconnect: Adv 6 Incorporation Losses Into The Circuit Model A series resistor, R, is included to account for conductor losses in both the power and ground plane A shunt resistor, G, is included to account for Dielectric Losses L R C G
Background image of page 6
7 Interconnect: Adv 7 DC Resistive Losses w t Reference Plane Current flows through entire cross section of signal conductor and ground plane wt L A L R tion cross DC ρ = = - sec At low frequencies, the current flowing in a conductor will spread out as much as possible DC losses are dominated by the cross sectional area & the resistively (inverse of conductivity) of the signal conductor The current in a typical ground plane will spread out so much that the DC plane resistance is negligible The DC losses of FR4 are very negligible
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 Interconnect: Adv 8 AC Resistive Losses As the frequency of a signal increases, the current will tend to migrate towards the periphery or “skin” of the conductor - This is known as the “skin effect”.
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/23/2009 for the course ECLT 762 taught by Professor Yinchaochen during the Spring '03 term at South Carolina.

Page1 / 32

Class21_InterconnectI - I nte rconne I class 21 ct Pre...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online