The AD5666 has an on-chip reference with an internal gain of 2. The AD5666-1 has a 1.25 V 5 ppm/°C reference, giving a full-scale output of 2.5 V; the AD5666-2 has a 2.5 V 5 ppm/°C reference, giving a full-scale output of 5 V. The on-board reference is off at power-up, allowing the use of an external reference. The internal reference is turned on by writing to the DAC.

The part incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V (POR pin low) or to midscale (POR pin high) and remains powered up at this level until a valid write takes place. The part contains a power-down feature that reduces the current consumption of the device to 400 nA at 5 V and provides software-selectable output loads while in power-down mode for any or all DAC channels.

The outputs of all DACs can be updated simultaneously using the LDAC function, with the added functionality of user-select-able DAC channels to simultaneously update. There is also an asynchronous CLR that clears all DACs to a software-selectable code—0 V, midscale, or full scale.

The AD5666 utilizes a versatile 3-wire serial interface that operates at clock rates of up to 50 MHz and is compatible with standard SPI®, QSPI™, MICROWIRE™, and DSP interface standards. The on-chip precision output amplifier enables rail-to-rail output swing.