A Low Drift Voltage Rfference Source

A voltage reference source has been developed using only NPN transistors and untrimmed base-layer resistors. A high speed bipolar oxide isolation process (fT= 4 GHz) was used for implementation. The excellent results, 1 mV drift for supply variations of ±10 % and temperature variation of 0 - 120°C, are comparable to those known from technologies especially adapted for precision analogue circuits. This was achieved by splitting up the circuit into one network for voltage regulation and another one for temperature regulation.