Features and Benefits

  • 12-/10-/8-bit ADCs with fast conversion time: 1 μs typical
  • 4 analog input channels/3 analog input channels with reference input
  • Specified for VDD of 2.7 V to 5.5 V
  • Sequencer operation
  • Temperature range: −40°C to +125°C
  • I2C-compatible serial interface supports standard, fast, and high speed modes
  • 2 versions allow 2 I2C addresses
  • Low power consumption
    Shutdown mode: 1 μA maximum
  • 8-lead SOT-23 package
  • Qualified for automotive applications

Product Details

The AD7991 / AD7995 / AD7999 are 12-/10-/8-bit, low power, successive approximation ADCs with an I2C®-compatible interface. Each part operates from a single 2.7 V to 5.5 V power supply and features a 1 μs conversion time. The track-and-hold amplifier allows each part to handle input frequencies of up to 14 MHz, and a multiplexer allows taking samples from four channels.

Each AD7991 / AD7995 / AD7999 provides a 2-wire serial interface compatible with I2C interfaces. The AD7991 and AD7995 come in two versions and each version has an individual I2C address. This allows two of the same devices to be connected to the same I2C bus. Both versions support standard, fast, and high speed I2C interface modes. The AD7999 comes in one version.

The AD7991 / AD7995 / AD7999 normally remain in a shutdown state, powering up only for conversions. The conversion process is controlled by a command mode, during which each I2C read operation initiates a conversion and returns the result over the I2C bus.

When four channels are used as analog inputs, the reference for the part is taken from VDD; this allows the widest dynamic input range to the ADC. Therefore, the analog input range to the ADC is 0 V to VDD;. An external reference, applied through the VIN3/VREF input, can also be used with this part.


  1. Four single-ended analog input channels, or three single-ended analog input channels and one reference input channel.
  2. I2C-compatible serial interface. Standard, fast, and high speed modes.
  3. Automatic shutdown.
  4. Reference derived from the power supply or external reference.
  5. 8-lead SOT-23 package.


  • System monitoring
  • Battery-powered systems
  • Data acquisition
  • Medical instruments

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.

Product Recommendations

AD7999 Companion Parts

Recommended External References - 2.5V

Recommended Input Buffer Amplifiers

  • For precision, high speed, low cost: AD8604.
  • For single supply, high speed, low power: AD8031, AD8032.
  • For low distortion, low noise, dual supplies: AD8599.
  • For precision, low noise, single supply: AD8605, AD8605.

Recommended Digital Isolators

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

See our Ordering FAQs for answers to questions about online orders, payment options and more.


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.

Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help