Multirange, +5V, 8-Channel, Serial 12-Bit ADCs

The MAX1270/MAX1271 are multirange, 12-bit data-acquisition 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 4-20mA, ±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, software-selectable internal/external clock, 110ksps throughput rate, and internal 4.096V or external reference operation.

The MAX1270/MAX1271 serial interface directly connects to SPI™/QSPI™ and MICROWIRE™ devices without external logic.

A hardware shutdown input (SHDN-bar) and two software-programmable 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.

The MAX1270/MAX1271 are available in 24-pin narrow DIP or space-saving 28-pin SSOP packages.

Applications

* Automatic Testing * Battery-Powered Instruments * Data Acquisition Systems * Industrial Control Systems * Medical Instruments * Robotics

* 12-Bit Resolution, 1/2LSB Linearity

* +5V Single-Supply Operation

* SPI/QSPI and MICROWIRE-Compatible 3-Wire Interface

* Four Software-Selectable Input Ranges

* MAX1270: 0 to +10V, 0 to +5V, ±10V, ±5V

* MAX1271: 0 to VREF, 0 to VREF/2, ±VREF, ±VREF/2

* Eight Analog Input Channels

* 110ksps Sampling Rate

* ±16.5V Overvoltage-Tolerant Input Multiplexer

* Internal 4.096V or External Reference

* Two Power-Down Modes

* Internal or External Clock

* 24-Pin Narrow DIP or 28-Pin SSOP Packages