AD7746
PRODUCTION24-bit, 2 Channel Capacitance to Digital Converter
- Part Models
- 3
- 1ku List Price
- Starting From $7.40
Overview
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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 fea-tures 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
Documentation
Data Sheet 1
Application Note 3
Technical Articles 2
Product Highlight 1
Evaluation Design File 1
Frequently Asked Question 1
Video 1
Device Drivers 2
Product Highlight 1
Circuit Note 1
Analog Dialogue 4
Webcast 1
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 |
|---|---|---|---|
| AD7746ARUZ | 16-Lead TSSOP | ||
| AD7746ARUZ-REEL | 16-Lead TSSOP | ||
| AD7746ARUZ-REEL7 | 16-Lead TSSOP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
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Jan 20, 2012 - 11_0218 Halogen Free Material Change for Certain TSSOP Products at Carsem |
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| AD7746ARUZ | PRODUCTION | |
| AD7746ARUZ-REEL | PRODUCTION | |
| AD7746ARUZ-REEL7 | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
Evaluation Software 1
EVAL-AD7746HDZ (Humidity Demo Board) Evaluation Software
Can't find the software or driver you need?
Evaluation Kits
AD7746 Evaluation Kit
Resources
Software
Reference Designs
Capacitance to Digital Converter with Extended Range
Part Used
Resources
Design & Integration Tools
Videos
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CN0552 Capacitance-Digital Conversion w/ Extended Range Circuitry