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AD7722:  CMOS, 16-Bit, 195 kSPS Sigma-Delta ADC

Product Details


The AD7722 is a complete low power, 16-bit, sigma-delta ADC. The part operates from a +5 V supply and accepts a differential input voltage range of 0 V to +2.5 V or ±1.25 V centered around a common-mode bias. The AD7722 provides 16-bit performance for input bandwidths up to 90.625 kHz. The part provides data at an output word rate of 195.3 kHz.

The analog input is continuously sampled by an analog modulator eliminating the need for external sample-and-hold circuitry. The modulator output is processed by two Finite Impulse Response (FIR) digital filters in series. The on-chip filtering reduces the external antialias requirements to first order, in most cases. The group delay for the filter is 215.5 µs, while the settling time for a step input is 431 µs. The sample rate, filter corner frequency, and output word rate are set by an external clock that is nominally 12.5 MHz.

Use of a single bit DAC in the modulator guarantees excellent linearity and dc accuracy. Endpoint accuracy is ensured by on-chip calibration. This calibration procedure minimizes the zero-scale and full-scale errors.

Conversion data is provided at the output register through a flexible serial port or a parallel port. This offers 3-wire, high speed interfacing to digital signal processors. The serial interface operates in an internal clocking (master) mode, whereby an internal serial data clock and framing pulse are device outputs. Additionally, two AD7722s can be configured with the serial data outputs connected together. Each converter alternately transmits its conversion data on a shared serial data line.

The part provides an accurate on-chip 2.5 V reference. A reference input/output function is provided to allow either the internal reference or an external system reference to be used as the reference source for the part.

The AD7722 is available in a 44-pin PQFP package and is specified over the industrial temperature range from –40°C to +85°C.

FEATURES and BENEFITS

  • 16-Bit Σ-Δ ADC
    - 64 x Oversampling Ratio
    - Up to 220 kSPS Output Word Rate
    - Low-Pass, Linear Phase Digital Filter
  • Inherently Monotonic
  • On-Chip 2.5 V Voltage Reference
  • Single-Supply 5 V
  • High Speed Parallel or Serial Interface

Functional Block Diagram for AD7722

Documentation

Title Content Type File Type
AD7722: 16-Bit, 195 kSPS CMOS, Σ-Δ ADC Data Sheet  (Rev B, 10/2003) (pdf, 447 kB) Data Sheets PDF
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging  (pdf, 217 kB) Application Notes PDF
AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:  (pdf, 149 kB)
The Most Common Causes and the Associated Fixes to Prevent Reoccurrence
Application Notes PDF
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change  (pdf, 76 kB) Application Notes PDF
AN-389: Using Sigma-Delta Converters-Part 2  (pdf, 590 kB)
When to Use/How to Use Sigma-Delta ADCs; Continuation of Part 1 Discussion.
Application Notes PDF
AN-388: Using Sigma-Delta Converters-Part 1  (pdf, 590 kB)
When to Use/How to Use Sigma-Delta ADCs
Application Notes PDF
AN-283: Sigma-Delta ADCs and DACs  (pdf, 1699 kB)
Overview of Sigma-Delta Concepts: Oversampling, Noise Shaping Using the Sigma-Delta Modulator, Digital Filtering and Decimation.
Application Notes PDF
MS-2210: Designing Power Supplies for High Speed ADC  (pdf, 327 kB) Technical Articles PDF
Delta-Sigma Rocks RF, As ADC Designers Jump On Jitter
(Electronic Design, 1/12/06)
Technical Articles HTML
Circuit Suggestions Using Features and Functionality of New Sigma-Delta ADCs Technical Articles HTML
Designing and Applying Remote Field Instruments
by Albert O' Grady and Jim Ryan, Analog Devices B.V.
...Good things can come in small packages because of on-chip capabilities
(Control Engineering, September 1998)
Technical Articles HTML
Ask the Applications Engineer-27: What problems am I most likely to run into when instrumenting an industrial system?
(Analog Dialogue, Vol. 33, No. 2, February, 1999)
Analog Dialogue HTML
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
Sigma-Delta ADC Tutorial
An interactive illustration showing the behavior of an idealized sigma-delta A/D converter.
Utilities and Conversions HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

AD7722 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD7722ASZ Status: Production PLASTIC QUAL FLATPACK/MQFP 44 Ind Tray, 96 $20.24 $17.20 Y  Material Info PCN Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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