The ADC080X family are CMOS 8-Bit, successive approximation A/D converters which use a modified  potentiometric ladder and are designed to operate with the  8080A control bus via three-state outputs. These converters  appear to the processor as memory locations or I/O ports,  and hence no interfacing logic is required. The differential analog voltage input has good common-mode-rejection and permits offsetting the analog zero-input- voltage value. In addition, the voltage reference input can be adjusted to allow encoding any smaller analog voltage span  to the full 8 bits of resolution