ZN427E-8 DA converter The ZN427 is an 8-bit successive approximation converter with three-state outputs to permit easy interfacing to a common data bus. The IC contains a voltage switching DAC, a fast comparator, successive approximation logic and a 2.56V precision bandgap reference, the use of which is pin optional to retain flexibility. An external fixed or varying reference may therefore be substituted, thus allowing ratiometic operation Only passive external components are required for operation of the converter.