AD7745

www.DataSheet4U.com 24-Bit Capacitance-to-Digital Converter with Temperature Sensor AD7745/AD7746 FEATURES Capacitance-to-digital converter New standard in single chip solutions Interfaces to single or differential floating sensors Resolution down to 4 aF (that is, up to 21 ENOB) Accuracy: 4 fF Linearity: 0.01% Common-mode (not changing) capacitance up to 17 pF Full-scale (changing) capacitance range: ±4 pF Tolerant of parasitic capacitance to ground up to 60 pF Update rate: 10 Hz to 90 Hz Simultaneous 50 Hz and 60 Hz rejection at 16 Hz Temperature sensor on-chip Resolution: 0.1°C, accuracy: ±2°C Voltage input channel Internal clock oscillator 2-wire serial interface (I2C®-compatible) Power 2.7 V to 5.25 V single-supply operation 0.7 mA current consumption Operating temperature: –40°C to +125°C 16-lead TSSOP package GENERAL DESCRIPTION The AD7745/AD7746 are a high resolution, Σ-Δ capacitance-todigital converter (CDC). The capacitance to be measured is connected directly to the device inputs. The architecture features inherent high resolution (24-bit no missing codes, up to 21-bit effective resolution), high linearity (±0.01%), and high accuracy (±4 fF factory calibrated). The AD7745/AD7746 capacitance input range is ±4 pF (changing), while it can accept up to 17 pF common-mode capacitance (not changing), which can be balanced by a programmable on-chip, digital-tocapacitance converter (CAPDAC). The AD7745 has one capacitance input channel, while the AD7746 has two channels. ...