MOS LOGIC

2004

The increasing frequency of operation and the larger number of transistors on the chip, along with slower decrease in supply voltage have led to more power dissipation and high chip power density which cause problems in chip thermal management and heat removal process. Therefore, low power circuit techniques have gained more attention in VLSI design. In this thesis, a high performance (2.9GHz) 32-bit adder is designed and is used as a benchmark for applying a low power technique without performance degradation. A dual supply technique for compound domino logic is proposed and is implemented in the adder. With this technique we have achieved an average power saving of 22% and 3.5% performance improvement over the conventional design. In addition to that, a novel carry select adder is introduced for power and area saving.

Year 1 Gbits 0.15-0.2µm 256 Mbits 0.25-0.3µm 4 Gbits 0.15µm 64 Mbits 0.35-0.4µm 16 Mbits 0.5-0.6µm

Boltzmann's constant Electron charge Thermal voltage Energy gap of silicon (Si) 109 106 103 second edition CMO S DIGITAL INTE GRATE D CI RCUITS

Year 1 Gbits 0.15-0.2µm 256 Mbits 0.25-0.3µm 4 Gbits 0.15µm 64 Mbits 0.35-0.4µm 16 Mbits 0.5-0.6µm

Boltzmann's constant Electron charge Thermal voltage Energy gap of silicon (Si) 109 106 103 second edition CMO S DIGITAL INTE GRATE D CI RCUITS

The effect of the well bias on the threshold voltage of an NMOS transistor is plotted in for typical values of |-2φ F | = 0.6 V and γ = 0.4 V 0.5 . A negative bias on the well or substrate causes the threshold to increase from 0.45 V to 0.85 V. Note also that V SB always has to be larger than -0.6 V in an NMOS. If not, the sourcebody diode becomes forward biased, which deteriorates the transistor operation.

digital integrated electronics

Boltzmann's constant Electron charge Thermal voltage Energy gap of silicon (Si) 109 106 103 second edition CMO S DIGITAL INTE GRATE D CI RCUITS

Boltzmann's constant Electron charge Thermal voltage Energy gap of silicon (Si) 109 106 103 second edition CMO S DIGITAL INTE GRATE D CI RCUITS