The AD7997/AD7998 are 8-channel， 10- and 12-bit， low power， successive approximation ADCs with an I2 C-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 I 2 C interfaces. Each part comes in two versions， AD7997-0/AD7998-0 and AD7997-1/AD7998-1， and each version allows at least two different I2 C addresses. The I2 C interface on the AD7997-0/AD7998-0 supports standard and fast I2 C interface modes. The I2 C interface on the AD7997-1/ AD7998-1 supports standard， fast， and high speed I2 C 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 I2 C 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.