AD7701ARS

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
0Vto +2.5V or ±2.5 V Analog Input Range
4kSPS Output Data Rate Flexible Serial Interface UItralow Power APPLICATIONS Industrial Process Control Weigh Scales Portable Instrumentation Remote Data Acquisition

GENERAL DESCRIPTION

 The AD7701ARS is a 16-bit ADC that uses a sigma-delta conversion technique. The analog input is continuously sampled by an analog modulator whose mean output duty cycle is proportional to the input signal. The modulator output is processed by an on-chip digital filter with a six-pole Gaussian response, which updates the output data register with 16-bit binary words at word rates up to 4kHz. The sampling rate, filter corner frequency, and output word rate are set by a master clock input that may be supplied externally, or by a crystal controlled on-chip clock oscillator.
The inherent linearity of the ADC is excellent and endpoint accuracy is ensured by self-calibration of zero and full scale, which may be initiated at any time. The 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, which has an asynchronous mode compatible with UARTs and two synchronous modes suitable for interfacing to shift registers or the serial ports of industry-standard microcontrollers.
CMOS construction ensures low power dissipation, and a power-down mode reduces the idle power consumption to only 10uW.

PRODUCT HIGHLIGHTS
1. The AD7701ARS offers 16-bit resolution coupled with outstand-ing 0.0015% accuracy.
2. No missing codes ensures true, usable,16-bit dynamic range, removing the need for programmable gain and level-setting circuitry.
3. The effects of temperature drift are eliminated by on-chip self-calibration, which removes zero and gain error. External circuits can also be included in the calibration loop to remove system offsets and gain errors.
4.A flexible synchronous/asynchronous interface allows the AD7701ARS to interface directly to UARTs or to the serial ports of industry-standard microcontrollers.
5. Low operating power consumption and an ultralow power standby mode make the AD7701ARS ideal for loop-powered remote sensing applications, or battery-powered portable instruments.

Feature