GENERAL DESCRIPTION
The AD5421 is a complete, loop-powered, 4 mA to 20 mA digital-to-analog converter (DAC) designed to meet the needs of smart transmitter manufacturers in the industrial control industry. The DAC provides a high precision, fully integrated, low cost solution in compact TSSOP and LFCSP packages.
The AD5421 includes a regulated voltage output that is used to power itself and other devices in the transmitter. This regulator provides a regulated 1.8 V to 12 V output voltage. The AD5421 also contains 1.22 V and 2.5 V references, thus eliminating the need for a discrete regulator and voltage reference.

FEATURES
   16-bit resolution and monotonicity
   Pin selectable NAMUR-compliant ranges
      4 mA to 20 mA
      3.8 mA to 21 mA
      3.2 mA to 24 mA
   NAMUR-compliant alarm currents
      Downscale alarm current = 3.2 mA
      Upscale alarm current = 22.8 mA/24 mA
   Total unadjusted error (TUE): 0.05% maximum
   INL error: 0.0035% FSR maximum
   Output TC: 3 ppm/°C typical
   Quiescent current: 300 µA maximum
   Flexible SPI-compatible serial digital interface
      with Schmitt triggered inputs
   On-chip fault alerts via FAULT pin or alarm current
   Automatic readback of fault register on each write cycle
   Slew rate control function
   Gain and offset adjust registers
   On-chip reference TC: 4 ppm/°C maximum
   Selectable regulated voltage output
   Loop voltage range: 5.5 V to 52 V
   Temperature range: −40°C to +105°C
   TSSOP and LFCSP packages

APPLICATIONS
   Industrial process control
   4 mA to 20 mA loop-powered transmitters
   Smart transmitters
   HART network connectivity