A programmable CMOS voltage reference based on a proportional summing circuit

This paper describes a new approach for design and implementation of programmable voltage reference based on current mode bandgap voltage reference and a proportional summing circuit. The circuit is simulated and fabricated with Chartered 0.35 um mixed-signal technology, and our measurements demonstrate that its temperature coefficient is plusmn35.07 ppm/degC from 0 to 100degC. The supply voltage is varied from 2.7-5 V and the varied voltage reference is about 5 mV. Depending on the state of the five VID inputs, an output voltage between 1.075 V and 1.85 V is programmed in 25 mV increments.