GENERAL DESCRIPTION

The AD7745/AD7746 are a high resolution, Σ-Δ capacitance-to-digital 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).

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

APPLICATIONS

Automotive, industrial, and medical systems for

Pressure measurement

Position sensing

Level sensing

Flowmeters

Humidity sensing

Impurity detection

AD7746屬于集成電路（IC） > ADC/DAC - 特殊用途。亞德諾半導(dǎo)體技術(shù)有限公司制造生產(chǎn)的AD7746ADC/DAC - 特殊用途該產(chǎn)品族中的產(chǎn)品可用于模擬和數(shù)字表示的信息轉(zhuǎn)換，適用于特定用例，或集成了通用數(shù)據(jù)轉(zhuǎn)換器中不常見的其他功能。例如針對(duì)超聲或汽車?yán)走_(dá)應(yīng)用集成了低噪聲放大器和可變?cè)鲆婕?jí)的器件、注重音頻和視頻的產(chǎn)品、在段碼式顯示器上集成顯示測(cè)量值功能的器件、集成輸入輸出電氣隔離的器件等。