AD5421BREZ-REEL7

The AD5421 is a complete, loop-powered 4 mA to 20 mA DAC designed to meet the needs of smart transmitter manufacturers in industrial control applications. As a fully integrated, high-precision, low-cost solution, the device is available in compact TSSOP and LFCSP packages. The AD5421 incorporates an on-chip regulated output to power itself and other devices in the transmitter. This regulator provides an adjustable output voltage from 1.8 V to 12 V. The device also integrates 1.22 V and 2.5 V voltage references, eliminating the need for discrete regulators and references. The AD5421 can be used with standard HART FSK protocol communication circuitry without affecting rated performance. The high-speed serial interface operates at up to 30 MHz and allows simple connection to popular microprocessors and microcontrollers via an SPI-compatible 3-wire interface. The AD5421 guarantees 16-bit monotonicity. Under typical conditions, integral nonlinearity is 0.0015%, offset error is 0.0012%, and gain error is 0.0006%. It is available in 28-lead TSSOP and 32-lead LFCSP packages, rated for the extended industrial temperature range of -40°C to +105°C.

Applications

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

Key features

• 16-bit resolution and monotonicity
• Pin-selectable NAMUR-compatible ranges: 4 mA to 20 mA, 3.8 mA to 21 mA, 3.2 mA to 24 mA
• NAMUR-compatible alarm currents: low alarm = 3.2 mA, high alarm = 22.8 mA/24 mA
• Total unadjusted error (TUE): 0.05% (maximum)
• Integral nonlinearity (INL) error: 0.0035% FSR (maximum)
• Output temperature coefficient: 3 ppm/°C (typical)
• Quiescent current: 300 μA (maximum)
• Flexible SPI-compatible serial digital interface with Schmitt trigger inputs
• On-chip fault alarm via FAULT pin or alarm current
• Automatic fault register readback on every write cycle
• Slew rate control
• Gain and offset adjustment registers
• On-chip reference temperature coefficient: 4 ppm/°C (maximum)
• Optional regulated output
• Loop voltage range: 5.5 V to 52 V
• Temperature range: −40°C to +105°C
• TSSOP and LFCSP packages