Frequency-Domain Analysis of Transmission Line Circuits (Part 3)

Transcription

1 Frequency-Doain Analyi of Traniion ine ircuit (Part 3 Dr. Joé Erneto Raya ánchez Outline Differential traniion line oon ode ignaling Differential ode ignaling Mode converion Even and odd ode -coupled lole traniion line theory Terination technique Differential or Mixed-Mode -paraeter

2 Differential Traniion ine For high data rate, differential ignaling i ore ued due to: Radiation i reduced (cancellation of field Receiver reject ignal that are coon to both line (high MRR at the receiver ignal voltage aplitude can be aller V 0v v V v 0v (M. Reo, Electroagnetic Field in a Microtrip ine 4

3 oon Mode ignaling A data rate go up, frequencie increae, line becoe antenna (both end and receive and corrupt the counication (BER, crotalk, etc E and H field addition outide oon tiulu (M. Reo, Differential Mode ignaling Uing differential excitation (differential traniion line, ot of the outide electroagnetic field cancel E and H field cancellation outide Differential tiulu (M. Reo, 005 6

4 Mode onverion I produced by ayetrie in the differential pair an caue a differential ignal to be converted to a coon ode ignal (radiation, crotalk, etc. (M. Reo, Even Mode and Odd Mode Practical differential pair operate at even and odd ode iultaneouly Even ode excited in phae with equal aplitude Odd ode driven 80º out of phae with equal aplitude E H E H Even Mode Odd Mode (H. Heck 00 8

5 Differential ignaling for High-peed ink Differential ignaling can operate at uch higher data rate High peed link operating in exce of ~ Gb/ ue differential ignaling (e.g. Infiniband, PI-Expre. In fact, differential ignal are already ued for high peed clock in dektop + - Differential Tranitter Differential Pair Differential Receiver (H. Heck 00 9 ole Traniion ine V(z β ω o I(z V ( z V I( z I + o + o e z z z e + V e jβ z + jβz o + I e jβ z + jβz o V(z+ z I(z+ z ω v p β ( z ( jω I( z ( z ( jω V ( z d V 0 I Y jωi jωv 0 V I jω jω Y 0

6 -oupled ole yetrical T z V (z z I (z z z V (z+ z I (z+ z z V (z I (z z z V (z+ z I (z+ z jω I I jω jω I I jω ω ( V + jω V j + + jω V jω + ( V -oupled ole yetrical T (cont jω I I jω jω I I jω ω ( V + jω V j + + jω V jω + ( V Y V V I V ( + jω jω I I ( + d V 0 I Y 0 V I

7 Matrice of -oupled T ( + ( + o v p?? 3 Even Mode in -oupled yetrical T ω ω j I I j j I I j ω ( V + jω V j + ω ω jω V jω( + V ince V V and I I j ( I ω + jω V The effective and are Hence + eff eff o even + v p even ( + 4

8 Even Mode in -oupled yetrical T (cont V V ; I I o even + v p even ( + (H. Mellitz 003 o-even i the characteritic ipedance of one of the conductor when the coupled line i operated in even ode 5 Odd Mode in -oupled yetrical T jω I I jω jω I I jω j + ω ( V + jω V jω V jω + ( V ince V V and I I j ( I ω j ( V ω + The effective and are Hence + eff eff o odd + v p odd ( ( + 6

9 Odd Mode in -oupled yetrical T (cont V V ; I I o odd + v p odd ( ( + (H. Mellitz 003 o-odd i the characteritic ipedance of one of the conductor when the coupled line i operated in odd ode 7 Ditributed apacitance in oupled ine (D. M. Pozar, Microwave Engineering, Wiley, 005 8

10 Ditributed apacitance in oupled ine (cont even ode odd ode (D. M. Pozar, Microwave Engineering, Wiley, o and v p for Even and Odd Mode If o i the characteritic ipedance of each iolated conductor, and v p i the propagation velocity or wave peed in each iolated conductor o vp ince + o even vp even ( + then o odd + v p odd ( ( o odd < o < o even v p even < vp + 0

11 Terination Technique A ingle-reitor terination for each conductor i not enough for coupled line Proper terination are needed to avoid reflection in both even and odd ode The ot coon terination network are the T and Pi configuration T-Terination R d R d Rc R R c ( d o odd o even o odd

12 Pi-Terination R d R c R c R d R c o even o even o even o odd o odd 3 Adding Buffer for Differential ignaling T or π network Differential to Differential Differential to ingle-ended T or π network T or π network ingle-ended to ingle-ended 4

13 -Paraeter for Two-oupled ine Port Port Port 3 Port 4 Four-port ingle-ended device Return o Inertion o Near End rotalk (NEXT Far End rotalk (FEXT (M. Reo, ingle-ended to Balanced -Paraeter Port Port 3 ingle-ended Port Port 4 Balanced port Balanced Balanced port tiulu Differential- Mode tiulu oon-mode tiulu Port Port Port Port Repone Differential- Mode Repone oon- Mode Repone Port Port Port Port DD DD D D DD DD D D D D D D Naing onvention: ode re., ode ti., port re., port ti. (M. Reo, 005 6

14 Balanced, Differential or Mixed-Mode -Para. (M. Reo, 005 7