The Intersil HI-7159A is a monolithic A/D converter that uses a unique dual slope technique which allows it to resolve input changes as small as 1 part in 200,000 (10V) without the use of critical external components. Its digital autozeroing feature virtually eliminates zero drift over temperature. The device is fabricated in Intersil' proprietary low noise BiMOS process, resulting in exceptional linearity and noise performance. The HI-7159A's resolution can be switched between a high resolution 200,000 count (51/2 digit) mode, and a high speed 20,000 count (41/2 digit) mode without any hardware modifications. In the 41/2 digit uncompensated mode, speeds of 60 conversions per second can be achieved. The HI-7159A is designed to be easily interfaced with most microprocessors through either of its three serial and one parallel interface modes. In the serial modes, any one of four common baud rates is available.