Features and Benefits

  • 12-Bit ADC with Fast Conversion Time: 2 µs
  • Eight Single-Ended Analog Input Channels
  • Specified for VDD of 2.7 V to 5.5 V
  • Low Power Consumption
  • Fast Throughput Rate: - 188 kSPS
  • Sequencer Operation
  • Automatic Cycle Mode
  • I2C® Compatible Serial Interface
  • I2C® Interface supports:
    Standard, Fast, and High-Speed Modes
  • Out of Range Indicator
  • Pin-Selectable Addressing via AS
  • Automatic Shutdown Mode: - 1 µA max

Product Details

The AD7997 / AD7998 are 8-channel, 10- and 12-bit, low power, successive approximation ADCs with an I2C-compatible interface. The parts operate from a single 2.7 V to 5.5 V power supply and feature a 2 µs conversion time. The parts contain an 8-channel multiplexer and track-and-hold amplifier that can handle input frequencies up to 11 MHz.

The AD7997 / AD7998 provide a 2-wire serial interface that is compatible with I2C interfaces. Each part comes in two versions, AD7997-0 / AD7998-0 and AD7997-1 / AD7998-1, and each version allows at least two different I2C addresses. The I2C interface on the AD7997-0/AD7998-0 supports standard and fast I2C interface modes. The I2C interface on the AD7997-1 / AD7998-1 supports standard, fast, and high speed I2C interface modes.

The AD7997 / AD7998 normally remain in a shutdown state while not converting, and power up only for conversions. The conversion process can be controlled using the CONVST pin, by a command mode where conversions occur across I2C write operations or an automatic conversion interval mode selected through software control.

The AD7997 / AD7998 require an external reference that should be applied to the REFIN pin and can be in the range of 1.2 V to VDD. This allows the widest dynamic input range to the ADC.

On-chip limit registers can be programmed with high and low limits for the conversion result, and an open-drain, 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.


  1. 2 µs conversion time with low power consumption.
  2. I2C-compatible serial interface with pin-selectable addresses. Two AD7997/AD7998 versions allow five AD7997/AD7998 devices to be connected to the same serial bus.
  3. The parts feature automatic shutdown while not converting to maximize power efficiency. Current consumption is 1 µA max when in shutdown mode at 3V.
  4. Reference can be driven up to the power supply.
  5. Out-of-range indicator that can be software disabled or enabled.
  6. One-shot and automatic conversion rates.
  7. Registers store minimum and maximum conversion results.

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 (1)

Software & Systems Requirements

Product Recommendations

AD7998 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

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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.