ABSTRACT
In this paper, a closed-form model for device variability has been derived to study the impact of device parameter variations on low-voltage mixed signal circuits. Based on this model, a projected 22nm technology is used to examine the effects of device parameter variation on both digital and analog circuits. For digital circuit, delay (tPHL) variation, noise margin (NMH and NML) variation for an inverter are investigated. Current variation of a current mirror, gain variation of a differential operational amplifier are considered for analog circuit analysis. Analytical simulation results suggest that, in most cases, overall variation increases as the supply voltage in digital circuits or overdrive voltage in analog circuit decreases. Analytical results also show that, NMH variation in a digital circuit is more sensitive to the process related issues than NML variation. Moreover, nominal value for NMH is higher than nominal value of NML when supply voltage is more than 0.8V.
