Using active components to perform voltage division in digital-to-analog conversion

The need for special processing steps for implementation of passive components on a VLSI chip has been a major stumbling block in integration of analog and digital circuits on the same chip. For example, the need for double polysilicon layers in implementing high-quality capacitors make integration of switched-capacitor circuits with digital circuits, which do not require double polysilicon and usually occupy the largest area on a silicon chip, not ideally cost-effective.