Analysis of the Effect of Bias Current on the Performance of MOS Current-Mode Logic Circuits

Abstract

This paper highlights the effect of the constant current source employed in the MOS current-mode logic. This bias current plays a significant role in the functionality of MCML circuits as it gets steered to the different branches present in the circuit. In addition to the variations in the power dissipation and delay generated, this paper also investigates the changes in the swing of the output voltage as the tail current is varied. Simulations are performed for three current values, namely 10 µA, 10nA, and 10pA, and their effect on numerous parameters has been discussed. A comparison between CMOS and MCML inverters for these different current values proves the efficiency of MCML at high supply voltages.