Add to Signal Chain Designer

AD7688:  500 kSPS 16- BIT Differential PulSAR® A/D Converter in µSOIC/QFN

Product Details

The AD7688 is a 16-bit, 500 kSPS, charge redistribution successive-approximation Analog-to-Digital Converter which operates from a single 5V power supply, VDD. It contains a very low power high-speed 16-bit sampling ADC with no missing codes, an internal conversion clock and a versatile serial interface port. The part also contains a low noise, wide bandwidth, very short aperture delay track/hold circuit. On the CNV rising edge, it samples the voltage difference between IN+ and IN- pins. The voltages on these pins usually swing in opposite phase between 0 V to REF. The reference voltage REF is applied externally and can be set up to the supply voltage.

Its power scales linearly with throughput.

The SPI compatible serial interface also features the ability, using the SDI input, to “Daisy chain” several ADCs on a single 3 wire bus and provides an optional Busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V or 5 V logic using the separate supply VIO.

The AD7688 is housed in a 10-lead µSOIC or 10-lead QFN (Chip Scale package) with operation


  • Battery Powered Equipment
  • Medical instruments
  • Mobile communications
  • Personal digital assistants
  • Data Acquisition
  • Instrumentation
  • Medical Instruments
  • Process Control

    • 16 Bits Resolution with No Missing 16-Bit Codes
    • Throughput: 500 kSPS
    • INL: ±0.4 LSB Typ, ±1.5 LSB Max
    • S/(N+D): 95 dB @ 20 kHz
    • Power Dissipation:
      4 mW @ 100 kSPS
      4 µW @ 100 SPS
    • True Differential Analog input range: ±VREF 0 V to VREF with VREF up to VDD on Both Inputs
    • No Pipeline Delay
    • Single Supply 5V Operation with 1.8V to 5 V Logic Interface
    • Multiple ADCs Daisy Chain, with BUSY Indicator
    • Serial Interface SPI/QSPI/Wire/DSP compatible
    • µSOIC Package (µSO8 Size) and 3 mm by 3 mm QFN (LFCSP) (SOT23 size)
    • Pin-to-Pin Compatible with the AD7685, AD7686, AD7687

    Functional Block Diagram for AD7688

    Similar Products

    High Resolution - Single Channel Unipolar/Bipolar 14/16/18-Bit PulSAR ADCs


    Title Content Type File Type
    AD7688: 16-Bit, 1.5 LSB INL, 500 kSPS PulSAR™ Differential ADC in MSOP/LFCSP Data Sheet (Rev B, 06/2014) (pdf, 669 kB) Data Sheets PDF
    Tested ADC Driver to PulSAR ADC Application Notes HTML
    AN-931: Understanding PulSAR ADC Support Circuitry  (pdf, 299 kB)
    This application note discusses in general the pitfalls that occur regularly when using SAR ADCs and, more importantly, how to easily prevent them.
    Application Notes PDF
    AN-932: Power Supply Sequencing  (pdf, 95 kB) Application Notes PDF
    AN-877: Interfacing to High Speed ADCs via SPI  (pdf, 1594 kB) Application Notes PDF
    AN-935: Designing an ADC Transformer-Coupled Front End  (pdf, 363 kB) Application Notes PDF
    AN-742: Frequency Domain Response of Switched-Capacitor ADCs  (pdf, 401 kB) Application Notes PDF
    The Data Conversion Handbook Design Handbooks HTML
    MT-031: Grounding Data Converters and Solving the Mystery of  (pdf, 144 kB) Tutorials PDF
    MT-002: What the Nyquist Criterion Means to Your Sampled Data System Design  (pdf, 152 kB) Tutorials PDF
    MT-001: Taking the Mystery out of the Infamous Formula, "SNR=6.02N + 1.76dB," and Why You Should Care  (pdf, 94 kB) Tutorials PDF
    UG-682: 6-Lead SOT-23 ADC Driver for the 8-/10-Lead Family of 14-/16-/18-Bit PulSAR ADC Evaluation Boards  (pdf, 433 kB) User Guides PDF
    UG-340: Evaluation Board for the 10-Lead Family 14-/16-/18-Bit PulSAR ADCs  (pdf, 4636 kB) User Guides PDF
    High Speed Op Amp Drives a 16-Bit, 1-MSPS Differential-Input A/D Converter
    (Analog Dialogue, Vol. 36, No. 6, November/December 2002)
    Analog Dialogue HTML
    MS-2210: Designing Power Supplies for High Speed ADC  (pdf, 327 kB) Technical Articles PDF
    MS-2022: Seven Steps to Successful Analog-to-Digital Signal Conversion (Noise Calculation for Proper Signal Conditioning)  (pdf, 277 kB) Technical Articles PDF
    MS-2124: Understanding AC Behaviors of High Speed ADCs  (pdf, 276 kB) Technical Articles PDF
    Nine Often Overlooked ADC Specifications  (pdf, 445 kB)
    Analog-to-digital converters (ADCs) have many specifications; some are more important for a given application than others. Understanding these specifications and controlling external devices affecting the ADC will lead to better performance.
    Technical Articles PDF
    Low-Power Data Conversion Technology Enhances Portability
    (Electropages, 10/5/2006)
    Product Reviews HTML
    Lowest-Power 16-Bit ADC Optimizes Portable Designs
    (eeProductCenter, 10/4/2006)
    Product Reviews HTML
    SAR ADC & Driver Quick-Match Guide  (pdf, 251 kB)
    Find drivers for ADI's most popular single-ended and differential SAR ADCs based on your specific application conditions.
    Product Selection Guide PDF
    8- to 18-Bit SAR ADCs ... From the Leader in High Performance Analog  (pdf, 1885 kB)
    8- to 18-Bit SAR ADCs with Sample Rates up to 3 MSPS -- The latest additions to ADI’s ADC portfolio offer unrivaled functionality in terms of channel count and power supply voltage, optimal power/speed ratios, and the smallest packages to meet the demands of any data acquisition application, including portable, industrial, medical, wireless, and communications.
    Overview PDF
    High Speed, High Accuracy 14-Bit, 16-Bit, and 18-Bit PulSAR ADCs  (pdf, 3826 kB)
    A PulSAR Family Brochure (6/2006)
    Overview PDF
    RAQs index Rarely Asked Questions HTML
    Glossary of EE Terms Glossary HTML

    Design Tools,Models,Drivers & Software

    Title Content Type File Type
    AD7685 IBIS Models IBIS Models HTML
    BeMicro FPGA Project for AD7688 with Nios driver FPGA HDL 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 Driver Amplifiers for the AD7688
    • For low frequency and low bias current, we recommend the ADA4627-1.
    • For precision, high dynamic range and high speed, we recommend the ADA4896 or the ADA4897-1.
    • For translating +/- 10V signals to 4V, low distortion, fast settling, we recommend the AD8275.
    Recommended External Voltage Reference for the AD7688
    • For best performance, we recommend the ADR435 or the ADR4550 (5V) reference.

    Recommended Digital Isolators for the AD7688
    • For a 4-channel, 150Mbps data rate, we recommend the ADuM3441.
    • For a 4- channel, 90Mbps data rate, we recommend the ADuM1401.
    • For a 3-channel, 90 Mbps data rate, we recommend the ADuM1301.
    Recommended Digital Isolators for the AD7688
    • For a 4-channel, 150Mbps data rate, we recommend the ADuM3441.
    Recommended Power Solutions
    • For selecting voltage regulator products, use ADIsimPower.

    Were these recommendations helpful?

    SampleSample & Buy

    Price, packaging, availability

    AD7688 Model Options
    Model Package Pins Temp.
    Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
    AD7688BCPZRL Status: Last Time Buy 10 ld LFCSP (3x3mm) 10 Ind Reel, 5000 - $15.13 Y  Material Info PDN Purchase
    AD7688BCPZRL7 Status: Production 10 ld LFCSP (3x3mm) 10 Ind Reel, 1500 - $15.13 Y  Material Info Notify Me Purchase Sample
    AD7688BRMZ Status: Production 10 ld MSOP 10 Ind Tube, 50 $16.74 $15.13 Y  Material Info PCN Purchase Sample
    AD7688BRMZRL7 Status: Production MICRO SOIC 10 Ind Reel, 1000 - $15.13 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.

    AD7688 Evaluation Board
    Model Description Price RoHS View PCN/ PDN Check Inventory/
    EVAL-AD7688-PMDZ Status: Production Evaluation Board PMOD compatible form factor $27.00 Yes -
    EVAL-AD7688SDZ Status: Production Evaluation Board SDP Interface $99.00 Yes -
    EVAL-SDP-CB1Z Status: Production Evaluation Controller Board SDP $99.00 Yes -
    SDP-PMD-IB1Z Status: Production Evaluation Interposer Board PMOD to SDP w/ Power Supply $55.00 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.

    Check Inventory & Purchase

    View Sales and Distribution Offices

    content here.
    content here.

    Review this Product