Patent ID: 6633246
Filing Date: 2003-10-14
Classification: H03M

Abstract:
A digital-to-analog converter (DAC), comprising:a voltage supply terminal, a multi-bit decrementing resistance network connected to said terminal and having resistance elements with temperature coefficients of resistance (TCR) within a first range, respective switches for the bits of said network, said switches having associated resistances with TCRs within a second range different from said first range, an output amplifier connected to receive an output signal from said resistance network, and a feedback circuit for said amplifier, comprising a compensation resistance element having a TCR within said second range for said resistances associated with said switches and connected in a combined series/parallel circuit with a feedback resistance circuit having a TCR within said first range for said resistance elements of said decrementing resistance network, said feedback circuit having an effective resistance with a TCR within said first range and approximately equal to a desired feedback resistance (Rfb) for said amplifier, and an effective resistance with a TCR within said second range to at least approximately compensate for voltage drops across said switches.