Analog Devices Inc. AD7703ARZ

Description
The AD7703 is a 20-bit analog-to-digital converter (ADC) that utilizes a sigma-delta conversion technique. It continuously samples the analog input using an analog modulator, with the mean output duty cycle proportional to the input signal. The modulator output is processed by a six-pole Gaussian low-pass digital filter, updating the output data register with 16-bit binary words at rates up to 4 kHz. The sampling rate, filter corner frequency, and output word rate are set by a master clock input, which can be supplied externally or generated by an on-chip crystal-controlled clock oscillator.
The AD7703 exhibits excellent inherent linearity, with endpoint accuracy ensured by self-calibration of zero and full scale, which can be initiated at any time. This self-calibration scheme can also be extended to null system offset and gain errors in the input channel.
The output data is accessed through a flexible serial port, featuring an asynchronous mode compatible with UARTs and two synchronous modes suitable for interfacing with shift registers or the serial ports of industry-standard microcontrollers.

Features
Monolithic 16-bit ADC
0.0015% linearity error
On-chip self-calibration circuitry
Programmable low-pass filter (0.1 Hz to 10 Hz corner frequency)
0 V to 2.5 V or ±2.5 V analog input range
4 KSPS output data rate
Flexible serial interface
Ultralow power

Applications
Industrial process control
Weigh scales
Portable instrumentation
Remote data acquisition