| 摘要 |
A single-chip 8-bit digital-to-analog converter (DAC) with bipolar current sources, an output buffer amplifier for developing an output voltage and a regulated reference for producing a calibrated output is operated by a single-voltage supply, e.g. +5 volts. The buffer amplifier includes means providing for driving the output voltage virtually to ground level when the DAC output is zero. The current sources comprise a single-transistor cell driven by an I<2>L flip-flop circuit, and the reference supply is merged with the reference transistor circuit regulating the DAC current levels, both aiding in reducing required chip area. On the amplifier, transistor Q40 has an additional element C3 which serves as an invalid mode collector when the amplifier output nears zero to prevent saturation of the transistor. <IMAGE> |
