Current-input current-output CMOS logarithmic amplifier based on translinear Ohm??s law

State-of-the-art logarithmic amplifiers use a transimpedance technique based on the exponential dependence between input current and output voltage as exhibited by p-n junction diodes, bipolar transistors and MOS transistors in the subthreshold region. Presented is a CMOS current-input current-output logarithmic amplifier based on a translinear Ohm´s law principle which involves a floating voltage source and a passive resistor embedded within a translinear loop. It is demonstrated that the input´output range of the proposed logarithmic amplifier can be controlled using a reference bias and the response of the amplifier can be temperature compensated using a PTAT and a resistive cancellation technique.