SNAD01 is a low cost serial 8-bits ADC with 8 individual input channels. Each channel can be independently programmed to a digital or analog input mode. In the analog input mode, this single-ended channel accepts an analog input signal from 0 to VREF and converts the signal into 12-bit digital codes (with 8-bit accuracy guaranteed). In the digital input mode, the channel can be treated as digital input port and the logic level appears at the channel can be acquired. SNAD01 has a synchronous 3-wires serial interface. Through this interface, the host CPU can easily control SNAD01. During A-to-D conversion, the typical current consumption is 500uA at 25kHz throughput-rate and +3V power supply. SNAD01 includes a power-down mode, which reduces maximum current consumption to less than 1uA. The reference voltage can be varied between 1V and +VCC, providing a corresponding input voltage range of 0V to VREF. SNAD01 also has an on-chip 1.17V bandgap reference that can be utilized for constant voltage input (especially for battery monitoring applications). The bandgap reference circuitry consumes 300mA@3v and can be enabled and disabled.