5V, Low-Power, Multichannel, Serial 8-Bit ADCs

The MAX1112/MAX1113 low-power, 8-bit, 8-channel analog-to-digital converters (ADCs) feature an internal track/hold, voltage reference, clock, and serial interface. They operate from a single 4.5V to 5.5V supply and consume only 135μA while sampling at rates up to 50ksps. The MAX1112's 8 analog inputs and the MAX1113's 4 analog inputs are software-configurable, allowing unipolar/bipolar and single-ended/differential operation.

Successive-approximation conversions are performed using either the internal clock or an external serial-interface clock. The full-scale analog input range is determined by the 4.096V internal reference, or by an externally applied reference ranging from 1V to VDD. The 4-wire serial interface is compatible with the SPI™, QSPI™, and MICROWIRE™ serial-interface standards. A serial-strobe output provides the end-of-conversion signal for interrupt-driven processors.

The MAX1112/MAX1113 have a software-programmable, 2µA automatic power-down mode to minimize power consumption. Using power-down, the supply current is reduced to 13µA at 1ksps, and only 82µA at 10ksps. Power-down can also be controlled using the active-low SHDN input pin. Accessing the serial interface automatically powers up the device.

The MAX1112 is available in a 20-pin SSOP package. The MAX1113 is available in a small 16-pin QSOP package.

Applications

* 4mA- to 20mA-Powered Remote Data-Acquisition Systems * Battery-Powered Applications * System Diagnostics * Touch-Screen Applications

* 4.5V to 5.5V Single Supply

* Low Power:

* 135µA at 50ksps

* 13µA at 1ksps

* 8-Channel Single-Ended or 4-Channel Differential Inputs (MAX1112)

* 4-Channel Single-Ended or 2-Channel Differential Inputs (MAX1113)

* Internal Track/Hold; 50kHz Sampling Rate

* Internal 4.096V Reference

* SPI/QSPI/MICROWIRE-Compatible Serial Interface

* Software-Configurable Unipolar or Bipolar Inputs

* Total Unadjusted Error:

* ±1 LSB (max)

* ±0.3 LSB (typ)