AD5668

The AD5628/AD5648/AD5668 devices are low power, octal, 12-/14-/16-bit, buffered voltage-output DACs. All devices operate from a single 2.7 V to 5.5 V supply and are guaranteed monotonic by design.

The AD5628/AD5648/AD5668 have an on-chip reference with an internal gain of 2. The AD5628/AD5648/AD5668-1 have a 1.25 V 5 ppm/°C reference, giving a full-scale output range of 2.5 V; the AD5628/AD5648/AD5668-2, -3 have a 2.5 V 5 ppm/°C reference, giving a full-scale output range of 5 V. The on-board reference is off at power-up, allowing the use of an external reference. The internal reference is enabled via a software write.

The part incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V (AD5628/AD5648/AD5668-1, -2) or midscale (AD5668-3) 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 userselectable DAC channels to simultaneously update. There is also an asynchronous CLR that updates all DACs to a userprogrammable code-zero scale, midscale, or full scale.

The AD5628/AD5648/AD5668 utilize 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.