Temperature independent log domain filter

Abstract

This paper presents the current mode log domain filter based on the Bernoulli cell which has moderately low sensitivity to temperature change. According to the simulation results in a standard 0.18μm CMOS process, the sensitivity of the output current over temperature of this log domain circuit is 2.941pA/°C. This is archived by using the modified current reference circuit which is directly proportion to temperature as the bias current for the log domain filter circuit. Additionally, this modified current reference circuit can be operated at low power supply voltage (1.11V) while high PSSR (0.43nA/V) is maintained. The power consumption of this modified current reference is in the sub-microwatt range (0.1μW).