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AD7921:  2-Channel, 2.35 V to 5.25 V, 250 kSPS, 12-Bit A/D Converter

Product Details

The AD7911/AD7921 are 10-bit and 12-bit, high speed, low power, 2-channel, successive-approximation ADCs respectively. The parts operate from a single 2.35 V to 5.25 V power supply and feature throughput rates up to 250 kSPS. The parts contain a low-noise, wide bandwidth track/hold amplifier, which can handle input frequencies in excess of 6 MHz.

The conversion process and data acquisition are controlled using CS and the serial clock, allowing the devices to interface with microprocessors or DSPs. The input signal is sampled on the falling edge of CS and the conversion is also initiated at this point. There are no pipeline delays associated with the part.

The channel to be converted is selected through the DIN pin and the mode of operation is controlled by CS. The serial data stream from the DOUT pin has a channel identifier bit, which provides information about the channel converted.

The AD7911/AD7921 use advanced design techniques to achieve very low power dissipation at high throughput rates.

The reference for the part is taken internally from VDD. This allows the widest dynamic input range to the ADC. Thus the analog input range for the part is 0 to VDD.

The conversion rate is determined by the SCLK.


  • Specified for VDD of 2.35 V to 5.25 V
  • Low Power:
    4 mW typ at 250 kSPS with 3 V Supplies
    13.5 mW typ at 250 kSPS with 5 V Supplies
  • Wide Input Bandwidth:
    71.5 dB Minimum SNR at 100 kHz Input Frequency
  • Flexible Power/Serial Clock Speed Management
  • Throughput Rate: 250 kSPS
  • No Pipeline Delays
  • High Speed Serial Interface SPI®/QSPI™ /MICROWIRE™ /DSP Compatible
  • Standby Mode: 1 µA max
  • 8-Lead TSOT Package
  • 8-Lead MSOP Package

Functional Block Diagram for AD7921

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For samples and technical information, please contact the ADC Development Group. Please include your name, company, address and a brief description of your application.


Title Content Type File Type
AD7911/AD7921: 2-Channel, 2.35 V to 5.25 V 250 KSPS, 10-/12-Bit ADCs Data Sheet  (Rev A, 05/2011) (pdf, 312 kB) Data Sheets PDF
MS-2210: Designing Power Supplies for High Speed ADC  (pdf, 327 kB) Technical Articles PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Evaluation Kits & Symbols & Footprints

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 Input Buffer Amplifiers for the AD7921

Recommended Precision References for the AD7921
  • For a low power, 5V Vdd supply, we recommend the REF195.
  • For a low power, 3V Vdd supply, we recommend the REF193 or the ADR433.
  • For a low power, 2.5V Vdd supply, we recommend the REF192 or the ADR421.
Recommended Power Solutions
  • For selecting voltage regulator products, use ADIsimPower.

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Price, packaging, availability

AD7921 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
AD7921ARMZ Status: Production 8 ld MSOP 8 Ind Tube, 50 $2.74 $2.33 Y  Material Info PCN Purchase Sample
AD7921ARMZ-REEL7 Status: Production 8 ld MSOP 8 Ind Reel, 1000 - $2.33 Y  Material Info PCN Purchase
AD7921AUJZ-REEL7 Status: Production 8 ld TSOT 8 Ind Reel, 3000 - $2.33 Y  Material Info PCN Purchase Sample
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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