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AD7291:  8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor

Product Details

Product Status:Recommended for New Designs

The AD7291 is a 12-bit, low power, 8-channel, successive approximation analog-to-digital converter (ADC) with an internal temperature sensor.

The part operates from a single 3.3 V power supply and features an I2C-compatible interface. The part contains a 9-channel multiplexer and a track-and-hold amplifier than can handle frequencies up to 30 MHz. The device has an on-chip 2.5 V reference that can be disabled to allow the use of an external reference.

The AD7291 provides a 2-wire serial interface compatible with I2C interfaces. The I2C interface supports standard and fast I2C interface modes. The AD7291 normally remains in a partial power-down state while not converting and powers up for conversions. The conversion process can be controlled by a command mode where conversions occur across I2C write operations or an autocycle mode selected through software control.

The AD7291 includes a high accuracy band gap temperature sensor, which is monitored and digitized by the 12-bit ADC to give a resolution of 0.25°C.

The AD7291 offers a programmable sequencer, which enables the selection of a preprogrammable sequence of channels for conversion.

On-chip limit registers can be programmed with high and low limits for the conversion results; an out-of-range indicator output (ALERT) becomes active when the programmed high or low limits are violated by the conversion result. This output can be used as an interrupt.

Product Highlights

  1. Ideally suited to monitoring system variables in a variety of systems including telecommunications, process control, and industrial control.
  2. I2C-compatible serial interface. Standard and fast modes.
  3. Automatic partial power-down while not converting to maximize power efficiency.
  4. Channel sequencer operation.
  5. Integrated temperature sensor with 0.25°C resolution.
  6. Out of range indicator that can be software disabled or enabled.


  • 12 bit SAR ADC
    -- 8 single-ended analog input channels
    -- Analog input range:
    0 V to 2.5 V
  • 12-bit temperature-to-digital converter
    -- Temperature sensor accuracy of ±1°C typical
  • Channel sequencer operation
  • Specified for VDD of 2.8 V to 3.6V
  • Logic Voltage VDRIVE = 1.65V to 3.6V
  • Internal 2.5V Reference
  • I2C-compatible serial interface supports standard and fast speed modes
  • Out of range indicator/alert function
  • Autocycle mode
  • Power-down current: 12 μA maximum
  • Temperature range: −40°C to +125°C
  • 20-lead LFCSP

Functional Block Diagram for AD7291

Additional Evaluation Board Information

If you purchase the evaluation board model of this model, you will also need the System Demonstration Platform (SDP).
They are used in conjunction as part of a customer evaluation enviroment. See below for EVAL-SDP-CB1Z ordering information.

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 High Accuracy, Precision External References - 2.5V for the AD7291
  • For applications requiring the lowest noise performance and output trim adjust, we recommend the ADR441.
  • For high output current applications, we recommend the ADR431.
  • For wide supply applications, we recommend the AD780.
  • For cost sensitive applications, we suggest the AD1582 or the ADR391.
Recommended Input Buffer Amplifiers for the AD7291
  • For applications requiring highest precision, we recommend the dual AD8606.
  • For applications requiring low cost, low temperature drift, good DC and AC precision, we recommend the dual AD8692.
  • For low power applications, we recommend the dual ADA4692-2.
  • For high speed, low noise, low distortion, we recommend the dual AD8022.
  • For a precision, battery-powered, instrumentation amplifier, we recommend the AD8420.
Recommended Power Solutions
  • For selecting voltage regulator products, use ADIsimPower.

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Price, packaging, availability

AD7291 Model Options
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.

AD7291 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
EVAL-AD7291SDZ Status: Production Evaluation Board $59.00 Yes -
EVAL-SDP-CB1Z Status: Production Evaluation Board $99.00 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.

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