AD7998

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 s 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.