AD7998 Datasheet

• 12-Bit ADC with Fast Conversion Time: 2 µs
• Eight Single-Ended Analog Input Channels
• Specified for V_DD 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

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

The 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 AD7998 require an external reference that should be applied to the REF_IN pin and can be in the range of 1.2 V to V_DD. 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.