AD5628:  Octal, 12-Bit, SPI Voltage Output denseDAC With 5 PPM/°C On-Chip Reference

The AD5628 device is a low power, octal, 12-bit, buffered voltage-output DAC. The device operates from a single 2.7 V to 5.5 V supply and is guaranteed monotonic by design. The AD5628 is available in both a 4 mm × 4 mm LFCSP and a 16-lead TSSOP.

The AD5628 has an on-chip reference with an internal gain of 2. The AD5628-1 has an 1.25 V 5 ppm/°C reference, giving a full-scale output range of 2.5 V; the AD5628-2, has 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 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-selectable DAC channels to simultaneously update. There is also an asynchronous CLR that updates all DACs to a user-programmable code—zero scale, midscale, or full scale.

The AD5628 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.

Product Highlights

• Octal, 12-bit DAC.
• On-chip 1.25 V/2.5 V, 5 ppm/°C reference.
• Available in 14-lead/16-lead TSSOP.
• Power-on reset to 0 V.
• Power-down capability. When powered down, the DAC typically consumes 200 nA at 3 V and 400 nA at 5 V.

Applications

• Process control
• Portable battery-powered instruments
• Digital gain and offset adjustment
• Programmable voltage and current sources
• Programmable attenuators