Tài liệu The Wire pptx

EE141 1 © Digital Integrated Circuits 2nd Wires Digital Integrated Digital Integrated Circuits Circuits A Design Perspective A Design Perspective The Wire The Wire Jan M. Rabaey Anantha Chandrakasan Borivoje Nikolic July 30, 2002 EE141 2 © Digital Integrated Circuits 2nd Wires The Wire The Wire transmitters receivers schematics physical EE141 3 © Digital Integrated Circuits 2nd Wires Interconnect Impact on Chip Interconnect Impact on Chip EE141 4 © Digital Integrated Circuits 2nd Wires Wire Models Wire Models All-inclusive model Capacitance-only EE141 5 © Digital Integrated Circuits 2nd Wires Impact of Interconnect Parasitics Impact of Interconnect Parasitics  Interconnect parasitics  reduce reliability  affect performance and power consumption  Classes of parasitics  Capacitive  Resistive  Inductive EE141 6 © Digital Integrated Circuits 2nd Wires 10 100 1,000 10,000 100,000 Length (u) No of nets (Log Scale) Pentium Pro (R) Pentium(R) II Pentium (MMX) Pentium (R) Pentium (R) II Nature of Interconnect Nature of Interconnect Local Interconnect Global Interconnect S Local = S Technology S Global = S Die Source: Intel EE141 7 © Digital Integrated Circuits 2nd Wires INTERCONNECT INTERCONNECT EE141 8 © Digital Integrated Circuits 2nd Wires Capacitance of Wire Interconnect Capacitance of Wire Interconnect V DD V DD V in V out M1 M2 M3 M4 C db2 C db1 C gd12 C w C g4 C g3 V out2 Fanout Interconnect V out V in C L Simplified Model EE141 9 © Digital Integrated Circuits 2nd Wires Capacitance: The Parallel Plate Model Capacitance: The Parallel Plate Model Dielectric Substrate L W H t di Electrical-field lines Current flow WL t c di di int ε = LL Cwire SSS S S 1 = ⋅ = EE141 10 © Digital Integrated Circuits 2nd Wires Permittivity Permittivity [...]... Digital Integrated Circuits2nd 23 Wires INTERCONNECT EE141 © Digital Integrated Circuits2nd 24 Wires Interconnect Modeling EE141 © Digital Integrated Circuits2nd 25 Wires The Lumped Model Vo ut cwi re Driver R d r iv e r Vout V in C lu m p e d EE141 © Digital Integrated Circuits2nd 26 Wires The Lumped RC-Model The Elmore Delay EE141 © Digital Integrated Circuits2nd 27 Wires The Ellmore Delay RC Chain EE141... Integrated Circuits2nd 11 Wires Fringing versus Parallel Plate (from [Bakoglu89]) EE141 © Digital Integrated Circuits2nd 12 Wires Interwire Capacitance fringing EE141 © Digital Integrated Circuits2nd parallel 13 Wires Impact of Interwire Capacitance (from [Bakoglu89]) EE141 © Digital Integrated Circuits2nd 14 Wires Wiring Capacitances (0.25 µ m CMOS) EE141 © Digital Integrated Circuits2nd 15 Wires INTERCONNECT... Circuits2nd 27 Wires The Ellmore Delay RC Chain EE141 © Digital Integrated Circuits2nd 28 Wires Wire Model Assume: Wire modeled by N equal-length segments For large values of N: EE141 © Digital Integrated Circuits2nd 29 Wires The Distributed RC-line EE141 © Digital Integrated Circuits2nd 30 Wires Step-response of RC wire as a function of time and space 2 5 x= L /10 2 x = L /4 vo lta g e (V) 1 5 x = L /2... 4 5 31 5 Wires RC-Models EE141 © Digital Integrated Circuits2nd 32 Wires Driving an RC-line Rs (r w,cw,L) V o ut V in EE141 © Digital Integrated Circuits2nd 33 Wires Design Rules of Thumb rc delays should only be considered when tpRC >> tpgate of the driving gate Lcrit >> √ tpgate/0.38rc  rc delays should only be considered when the rise (fall) time at the line input is smaller than RC, the rise (fall)... should only be considered when the rise (fall) time at the line input is smaller than RC, the rise (fall) time of the line trise < RC   when not met, the change in the signal is slower than the propagation delay of the wire EE141 © Digital Integrated Circuits2nd © MJIrwin, PSU, 2000 34 Wires ... Circuits2nd 16 Wires Wire Resistance R=ρ L HW Sheet Resistance Ro L H W EE141 © Digital Integrated Circuits2nd R1 R2 17 Wires Interconnect Resistance EE141 © Digital Integrated Circuits2nd 18 Wires Dealing with Resistance  Selective Technology Scaling  Use Better Interconnect Materials  reduce average wire- length  e.g copper, silicides  More Interconnect Layers  reduce average wire- length EE141... EE141 © Digital Integrated Circuits2nd 19 Wires Polycide Gate MOSFET Silicide PolySilicon SiO2 n+ n+ p Silicides: WSi 2, TiSi 2, PtSi 2 and TaSi Conductivity: 8-10 times better than Poly EE141 © Digital Integrated Circuits2nd 20 Wires Sheet Resistance EE141 © Digital Integrated Circuits2nd 21 Wires Modern Interconnect EE141 © Digital Integrated Circuits2nd 22 Wires Example: Intel 0.25 micron Process . Integrated Circuits 2nd Wires The Wire The Wire transmitters receivers schematics physical EE141 3 © Digital Integrated Circuits 2nd Wires Interconnect Impact. Integrated Circuits 2nd Wires Digital Integrated Digital Integrated Circuits Circuits A Design Perspective A Design Perspective The Wire The Wire Jan M. Rabaey