AD7745

PRODUCTION

24-bit, 1 Channel Capacitance to Digital Converter

Data Sheet (Rev. 0) Product Selection Table

Part Models: 3
1ku List Price: Starting From $5.65

Viewing:

Overview

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

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-to-capacitance converter (CAPDAC).

The AD7745 has one capacitance input channel, while the AD7746 has two channels. Each channel can be configured as single-ended or differential. The AD7745/AD7746 are designed for floating capacitive sensors. For capacitive sensors with one plate connected to ground, the AD7747 is recommended.

The parts have an on-chip temperature sensor with a resolution of 0.1°C and accuracy of ±2°C. The on-chip voltage reference and the on-chip clock generator eliminate the need for any external components in capacitive sensor applications. The parts have a standard voltage input, which together with the differential reference input allows easy interface to an external temperature sensor, such as an RTD, thermistor, or diode.

The AD7745/AD7746 have a 2-wire, I²C-compatible serial interface. Both parts can operate with a single power supply from 2.7 V to 5.25 V. They are specified over the automotive temperature range of –40°C to +125°C and are housed in a 16-lead TSSOP package.

Applications

Automotive, Industrial and Medical Systems for:

Pressure Measurement
Position Sensors
Level Sensors
Flowmeters
Humidity Sensors
Impurity Detection

Part Models: 3
1ku List Price: Starting From $5.65

Documentation

Frequently Asked Question 1

FAQ 03/20/2018

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
AD7745ARUZ	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7745ARUZ-REEL	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7745ARUZ-REEL7	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 5, 2021 - 21_0035 Amkor Philippines as an Alternate Site for TSSOP_4.4
		PCN21_0035_Form Material_Report Qualification Results Summary Other
AD7745ARUZ	PRODUCTION
AD7745ARUZ-REEL	PRODUCTION
AD7745ARUZ-REEL7	PRODUCTION
Jan 20, 2012 - 11_0218 Halogen Free Material Change for Certain TSSOP Products at Carsem
		PCN11_0218_Form Material_Report Qualification Report Summary
AD7745ARUZ	PRODUCTION
AD7745ARUZ-REEL	PRODUCTION
AD7745ARUZ-REEL7	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

Device Drivers 2

Can't find the software or driver you need?

Evaluation Kits

AD7746 Evaluation Kit

Buy Now View Details

Product Details

The EVAL-AD7746EBZ is a fully featured evaluation board for the AD7746. The evaluation board is operated with a PC via a standard USB connection with software provided enabling the user to perform detailed analysis of the CDC's performance. This software includes the technical note describing the operation and set up of the evaluation board.