The MAX1270/MAX1271 are multirange, 12-bit dataacquisition systems (DAS) that require only a single +5V supply for operation, yet accept signals at their analog inputs that may span above the power-supply rail and below ground. These systems provide eight analog input channels that are independently software programmable for a variety of ranges: 10V, 5V, 0 to +10V, 0 to +5V for the MAX1270; VREF, VREF/2, 0 to VREF, 0 to VREF/2 for the MAX1271. This range switching increases the effective dynamic range to 14 bits and provides the flexibility to interface 420mA, 12V, and 15V powered sensors directly to a single +5V system. In addition, these converters are fault protected to 16.5V; a fault condition on any channel will not affect the conversion result of the selected channel. Other features include a 5MHz bandwidth track/hold, softwareselectable internal/external clock, 110ksps throughput rate, and internal 4.096V or external reference operation. The MAX1270/MAX1271 serial interface directly connects to SPITM/QSPITM and MICROWIRETM devices without external logic. A hardware shutdown input (SHDN) and two softwareprogrammable power-down modes, standby (STBYPD) or full power-down (FULLPD), are provided for low-current shutdown between conversions. In standby mode, the reference buffer remains active, eliminating start-up delays.