On-Chip Communication Architectures

174 CHAPTER 5 Models for Power and Thermal Estimation

where a constant temperature increase is attributed to each wire due to this effect,

and the lower layers are assumed to be carrying current at their maximum density

j

max

. 

i

is a coverage factor that represents the probability of a wire being thermally

coupled to another wire in the lower layer, and is given a value 0.5 [91], and 

j

is

the resistivity of the metal line (Cu), depicted as resistance R

i



in Fig. 5.18 .

The thermal bus models presented in this section can be used to guide

designers during bus architecture design. For instance, the thermal model from

Sundaresan and Mahapatra ...