General Description
The MAX1403 18-bit, low-power, multichannel, serial output analog-to-digital converter (ADC) features matched 200µA current sources for sensor excitation. This ADC uses a sigma-delta modulator with a digital decimation filter to achieve 16-bit accuracy. The digital filter’s user-selectable decimation factor allows the conversion resolution to be reduced in exchange for a higher output data rate. True 16-bit performance is achieved at an output data rate of up to 480sps. In addition, the modulator sampling frequency may be optimized for either lowest power dissipation or highest throughput rate. The MAX1403 operates from +3V.

Features
♦ 18-Bit Resolution, Sigma-Delta ADC
♦ 16-Bit Accuracy with No Missing Codes to 480sps
♦ Matched On-Board Current Sources (200µA) for Sensor Excitation
♦ Low Quiescent Current
    250µA (operating mode)
    2µA (power-down mode)
♦ 3 Fully Differential or 5 Pseudo-Differential Signal Input Channels
♦ 2 Additional, Fully Differential Calibration Channels/Auxiliary Input Channels
♦ Programmable Gain and Offset
♦ Fully Differential Reference Inputs
♦ Converts Continuously or On Command
♦ Automatic Channel Scanning and Continuous Data Output Mode
♦ Operates with Analog and Digital Supplies from +2.7V to +3.6V
♦ SPI™/QSPI™-Compatible 3-Wire Serial Interface
♦ 28-Pin SSOP Package

Applications
    Portable Industrial Instruments
    Portable Weigh Scales
    Loop-Powered Systems
    Pressure Transducers