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AD7721:  CMOS, 12-/16-Bit, 312.5 kHz/468.75 kHz Sigma-Delta ADC

The AD7721 is a complete low power, 12-/16-bit, sigma-delta ADC. The part operates from a +5 V supply and accepts a differential input of 0 V to 2.5 V or ±1.25 V. The analog input is continuously sampled by an analog modulator at twice the clock frequency eliminating the need for external sample-and-hold circuitry. The modulator output is processed by two finite impulse response (FIR) digital ...More

AD7721:  CMOS, 12-/16-Bit, 312.5 kHz/468.75 kHz Sigma-Delta ADC

Product Description

The AD7721 is a complete low power, 12-/16-bit, sigma-delta ADC. The part operates from a +5 V supply and accepts a differential input of 0 V to 2.5 V or ±1.25 V. The analog input is continuously sampled by an analog modulator at twice the clock frequency 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. Settling time for a step input is 218.4 µs while the group delay for the filter is 109.2 µs when the master clock equals 15 MHz.

The AD7721 can be operated with input bandwidths up to 229.2 kHz. The corresponding output word rate is 468.75 kHz. The part can be operated with lower clock frequencies also. The sample rate, filter corner frequency, settling time, group delay and output word rate will be reduced also, as these are proportional to the external clock frequency. The maximum clock frequencies in parallel mode and serial mode are 10 MHz and 15 MHz respectively.

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

The output data is accessed from the output register through a serial or parallel port. This offers easy, high speed interfacing to modern microcontrollers and digital signal processors. The serial interface operates in internal clocking (master) mode, the AD7721 providing the serial clock.

CMOS construction ensures low power dissipation while a power-down mode reduces the power consumption to only 100 µW.

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  • 16-Bit Sigma-Delta ADC
  • 468.75 kHz Output Word Rate (OWR)
  • No Missing Codes
  • Low-Pass Digital Filter
  • High Speed Serial Interface
  • Linear Phase
  • 229.2 kHz Input Bandwidth
  • Power Supplies: AVDD, DVDD: +5 V ± 5%
  • Standby Mode (70 µW)
  • Parallel Mode (12-Bit/312.5 kHz OWR)
  • Resolution (Bits): 16bit
  • T-Put Rate: 468.75kSPS
  • # Chan: 1
  • Supply V: Single(+5)
  • Pwr Diss: 150mW
  • Interface: Par,Ser
  • Ain Range: (Vref) p-p,Uni (Vref)
  • SNR (dB): n/a
  • Pkg Type: DIP,SOIC

Functional Block Diagram for AD7721

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Part# Bits Throughput Rate # of Inputs Operating Pwr Diss
AD7980 16 1MSPS 1 10mW
AD7621 16 3MSPS 1 86mW
AD7622 16 2MSPS 1 85mW
AD7623 16 1.33MSPS 1 55mW
AD7625 16 6MSPS 1 145mW
AD7626 16 10MSPS 1 150mW
AD7650 16 570KSPS 1 115mW
AD7652 16 500KSPS 1 90mW
AD7653 16 1MSPS 1 145mW
AD7983 16 1.33MSPS 1 12mW
AD7664 16 570KSPS 1 115mW
AD7665 16 570KSPS 1 107mW
AD7666 16 500KSPS 1 90mW
AD7667 16 1MSPS 1 145mW
AD7671 16 1MSPS 1 125mW
AD7676 16 500KSPS 1 74mW
AD7677 16 1MSPS 1 130mW
AD7686 16 500KSPS 1 21.5mW
AD7688 16 500KSPS 1 21.5mW
AD7693 16 500KSPS 1 21.5mW
AD7400A 16 10MSPS 1 95mW
AD7401 16 20MSPS 1 100mW
AD7401A 16 20MSPS 1 105mW
AD7721 16 468.75KSPS 1 150mW
AD7400 16 10MSPS 1 90mW
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Model
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The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

For detailed drawings and chemical composition please consult our  Package Site

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  • Commercial: 0 to +70 degrees Celsius
  • Military : -55 to +125 degrees Celsius
  • Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
  • Automotive: -40 to +125 degrees Celsius
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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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Due to environmental concerns, ADI offers many of our products in lead-free versions. For more information about lead-free parts, please consult our Pb (Lead) free information page.

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This is the list of Product Change Notifications (PCN) published on the web for this model. Click on the link to access PCN Information.Only select pre-2009 PCN�s are available on-line. To obtain a pre-2009 PCN, contact your ADI Sales Rep. For more information on ADI's PCN process, please visit our PCN Policy Statement page

*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.
**Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.