Method and circuit for compensating vt inducted drift in monolithic logarithmic amplifier

摘要

A temperature-compensated monolithic logarithmic amplifier includes a logarithmic amplifier cell (26) configured to produce a logarithmic voltage signal (V3) representative of a difference between a first voltage (V1) developed across a first PN junction device (D1) in response to an input signal (Iin) and a second voltage (V2) developed across a second PN junction device (D2) in response to a reference signal (Iref) and an output circuit (36) including an output amplifier (19), a temperature-dependent first resistive element (R1) having a positive temperature coefficient, and a second resistive element (R2) . The output circuit (36) produces a temperature-compensated output signal (vout) in response to the logarithmic voltage signal (V3). The first resistive element (R1) is composed of conductive aluminum or aluminum alloy interconnection metallization that also is utilized as interconnection metallization throughout the monolithic logarithmic amplifier.