On-Chip Communication Architectures

172 CHAPTER 5 Models for Power and Thermal Estimation

For wires at the edges,

PC

tR R

ii

ii

i

ii

 









d

d

inter

 ()( )

01

(5.39)

For wires in the middle,

PC

tR R

ii

ii

i

ii i

 









d

d

inter

  ()( )

011

2

(5.40)

where P

i

is the instantaneous power dissipated in the ith wire, and 

i

is the ambi-

ent temperature (45°C or 318.15K). C

i

is the thermal capacitance per unit length

of the wire, given as:

CCtw

iii



s

()

(5.41)

where C

s

is the specifi c heat per unit volume of the metal, w

i

is the wire width,

and t

i

is the wire thickness, as shown in Fig. 5.19 . R

i

is the thermal resistance per

C

inter

C

inter

C

inter

C

inter

C

line

C

line

C

line

C

line ...