Current-mode Temperature Compensation for a Differential Logarithmic Amplifier in 180nm BiCMOS

摘要

This paper presents a new approach for the temperature compensation of a diode-based logarithmic amplifier used in on-chip power measurement circuitry. The output voltages of the amplifier are first converted into current domain. Then, the temperature compensation is realized using a translinear circuit and a PTAT current source. As most millimeter-wave systems on chip already contain a PTAT current generator, and the temperature compensation uses only devices readily available in commercial BiCMOS technologies, the presented approach is viable for many different designs. Simulation results of the compensation circuit together with an exemplary log amp show cancellation of the temperature dependence between -40°C and 125 °C with a dynamic range of 50 dB.