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AD7705:  3V/5V, 1 mW, 2-Channel Differential, 16-Bit Sigma-Delta ADC

Product Details


See also AD7792 16-Bit Sigma-Delta ADC with current sources

The AD7705 and AD7706 are complete 16-bit, low-cost, Sigma Delta ADCs intended for dc and low-frequency ac measurement applications. Their low power (1 mW max @ 3 V) allows them to be used in loop-powered, battery-powered or locally-powered applications. The on-chip Programmable Gain Amplifier with gain settings from I through 128 can accommodate both low-level and high-level analog inputs with no external signal conditioning hardware.

The AD7705 has two differential channels while the AD7706 has one differential and two pseudo-differential channels. Differential reference inputs also allow maximum flexibility in tailoring the device for use in ratiometric applications.

FEATURES and BENEFITS

  • Two Fully Differential Input Channel ADCs
  • Programmable Gain Front End
    Gains from 1 to 128
  • Three-Wire Serial Interface
    SPI®, QSPI™, MICROWIRE™ and DSP Compatible
    Schmitt Trigger Input on SCLK
  • Ability to Buffer the Analog Input
  • 2.7 V to 3.3 V or 4.75 V to 5.25 V Operation
  • Power Dissipation 1 mW max @ 3 V
  • Standby Current 8 µA max
  • 16-Lead DIP, 16-Lead SOIC and TSSOP Packages

Functional Block Diagram for AD7705

Documentation

Title Content Type File Type
AD7705/AD7706: 3V/5V, 1 mW, 2-/3-Channel, 16-Bit, Sigma-Delta ADC Data Sheet  (Rev C, 05/2006) (pdf, 460 kB) Data Sheets PDF
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging  (pdf, 217 kB) Application Notes PDF
AN-282: Fundamentals of Sampled Data Systems  (pdf, 2131 kB) Application Notes PDF
AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC  (pdf, 222 kB) Application Notes PDF
AN-615: Peak-to-Peak Resolution Versus Effective Resolution  (pdf, 70 kB)
This application note describes effective resolution and peak-to-peak resolution and highlights the difference between these two specifications.
Application Notes PDF
AN-101: Cross Plot Generator Allows Quick A/D Converter Evaluation  (pdf, 280 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-347: Shielding and Guarding  (pdf, 688 kB)
How to Exclude Interference-Type Noise. What to do and Why to do it-A Rational Approach
Application Notes PDF
AN-342: Analog Signal-Handling for High Speed and Accuracy.  (pdf, 468 kB)
Signal handling techniques for optimizing DAC and ADC performance.
Application Notes PDF
AN-280: Mixed Signal Circuit Technologies  (pdf, 2101 kB)
Considers problems which arise when reality (& Murphy) intervene in a design which otherwise seems satisfactory in terms of theory and modeling.
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
Harness the Power of Sigma-Delta and Switched Capacitor Technologies in Signal Processing Components
... You can have low-power operation, 16-bit accuracy, and onchip calibration by using state-of-the-art design techniques. (Sensors Online, November 1998)
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
How do I use the serial interface on the AD7705/06/07 ADC? FAQs/RAQs HTML
What are the general design considerations when using the AD7705/06/07 ADC? FAQs/RAQs HTML
What are the calibration options on the AD7705/06/07 ADC? FAQs/RAQs HTML
What Architecture is used in the AD7705/06/07 ADC? FAQs/RAQs HTML
How do I get the best performance from the AD7705/06/07 ADC? FAQs/RAQs 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
Sigma Delta Register Configuration Assistant
Easily program the configuration registers for the sigma delta ADCs. Use pull-down menus to determine the correct hex values to load into the registers, and generate pseudo-code.
Design Calculators 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.

Product Recommendations & Reference Designs

Companion Products

Suggested Companion Products


Recommended Voltage References for the AD7705

  • For precision 2.5V applications with AVdd = 5V, we recommend AD780, REF43 or the REF192.
  • For precision 1.2V applications with AVdd = 3V, we recommend the AD589, AD1580 or the ADR512.
Recommended Digital Isolators for the AD7705
  • For optocoupler alternatives, see our digital isolator selection tables, ADuMxxxx.
  • For process control applications, we recommend the ADuM1400 and the ADuM1200 icoupler.
  • For isolated USB designs in healthcare and industrial control, we recommend the ADuM4160.
Recommended Power Solutions
  • For selecting voltage regulator products, use ADIsimPower.

Were these recommendations helpful?

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Price, packaging, availability

AD7705 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD7705BN Status: Production 16 ld PDIP 16 Ind Tube, 25 $5.85 $4.96 N  Material Info PCN Purchase
AD7705BNZ Status: Production 16 ld PDIP 16 Ind Tube, 25 $5.06 $4.29 Y  Material Info PCN Purchase Sample
AD7705BR Status: Production 16 ld SOIC - Wide 16 Ind Tube, 47 $5.67 $4.81 N  Material Info PCN Purchase
AD7705BR-REEL Status: Production 16 ld SOIC - Wide 16 Ind Reel, 1000 - $4.81 N  Material Info PCN Purchase
AD7705BRU Status: Production 16 ld TSSOP 16 Ind Tube, 96 $5.67 $4.81 N  Material Info PCN Purchase
AD7705BRU-REEL Status: Last Time Buy 16 ld TSSOP 16 Ind Reel, 2500 - $4.81 N  Material Info PCN/PDN Purchase
AD7705BRU-REEL7 Status: Production 16 ld TSSOP 16 Ind Reel, 1000 - $4.81 N  Material Info PCN Purchase
AD7705BRUZ Status: Production 16 ld TSSOP 16 Ind Tube, 96 $4.91 $4.17 Y  Material Info PCN Purchase Sample
AD7705BRUZ-REEL Status: Production 16 ld TSSOP 16 Ind Reel, 2500 - $4.17 Y  Material Info PCN Purchase
AD7705BRUZ-REEL7 Status: Production 16 ld TSSOP 16 Ind Reel, 1000 - $4.17 Y  Material Info PCN Purchase
AD7705BRZ Status: Production 16 ld SOIC - Wide 16 Ind Tube, 47 $4.91 $4.17 Y  Material Info PCN Purchase Sample
AD7705BRZ-REEL Status: Production 16 ld SOIC - Wide 16 Ind Reel, 1000 - $4.17 Y  Material Info PCN Purchase
AD7705BRZ-REEL7 Status: Production 16 ld SOIC - Wide 16 Ind Reel, 400 $4.91 $4.17 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.

AD7705 Evaluation Kit
Model Description Price RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
EVAL-AD7705EBZ Status: Production Evaluation Board $151.80 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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