Features and Benefits

  • 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

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

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (2)

Software & Systems Requirements

Tools & Simulations

Precision ADC Driver Tool

The Precision ADC Driver Tool is a web application that simulates the performance of precision ADC and driver combinations. Potential issues with driver selection, kickback settling, and distortion are flagged, and design tradeoffs can be quickly evaluated. Simulations and calculations include system noise, distortion, and settling of the ADC input

Precision ADC Driver Tool

IBIS Models

AD7685 IBIS Models

Product Recommendations

AD7688 Companion Parts

Recommended Digital Isolators

  • For SPI Interface, low power, 5.0 kVrms isolation: ADUM4401.
  • For SPI Interface, smallest package, low voltage I/O (1.8 V to 5.5 V): ADUM3481.
  • For SPI Interface, enhanced system-level ESD performance, 2.5 kVrms isolation: ADUM3401.
  • For SPI Interface, lowest power, 2.5 kVrms isolation: ADUM1401.

Recommended Driver Amplifiers

Recommended External Voltage Reference

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

Sample & Buy

Sample & Buy functionality exists in desktop site
Check Inventory

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.

Price Table Help

Evaluation Boards Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
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.