The reference circuit, containing a buried zener, is lasertrimmed for minimum temperature coefficient. The clock oscillator is current-controlled for excellent stability over temperature. Full-scale and offset errors may be externally trimmed to zero. Internal scaling resistors are provided for the selection of analog input signal ranges of 0V to +10V, 0V to +20V, 5V, and 10V. The converter may be externally programmed to provide 8- or 12-bit resolution. The conversion time for 12 bits is factory set for 8.5s maximum.