A Novel mA Level PTAT Current Generator Technique

An accurate PTAT current at mA levels is often required for biasing bipolar amplifiers in order to achieve gain flatness over a specific temperature range. However, this is often difficult to achieve without the use of an operational amplifier (op-amp). This work presents two 2.5mA proportional to absolute temperature (PTAT) current generator circuits, based on a technique that is the subject of a patent application. Simulation measurements show an output temperature coefficient (TC) within 15ppm/degC of the reference current over the temperature range of -40degC to +85degC, and a rail supply sensitivity of less than 0.32%. This is achieved without the use of an operational amplifier