Catalog
16-Bit, Serial Input, Loop-Powered, 4mA to 20mA DAC
Key Features
• 16-bit resolution and monotonicity
• Pin selectable NAMUR-compliant ranges4 mA to 20 mA3.8 mA to 21 mA3.2 mA to 24 mA
• 4 mA to 20 mA
• 3.8 mA to 21 mA
• 3.2 mA to 24 mA
• NAMUR-compliant alarm currentsDownscale alarm current = 3.2 mAUpscale alarm current = 22.8 mA/24 mA
• 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
Description
AI
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.The AD5421 can be used with standard Highway Addressable Remote Transducer (HART®) FSK protocol communication circuitry without any degradation in specified performance. The high speed serial interface is capable of operating at 30 MHz and allows for simple connection to commonly used microprocessors and microcontrollers via a SPI-compatible, 3-wire interface.The AD5421 is guaranteed monotonic to 16 bits. It provides 0.0015% integral nonlinearity, 0.0012% offset error, and 0.0006% gain error under typical conditions.The AD5421 is available in a 28-lead TSSOP and a 32-lead LFCSP specified over the extended industrial temperature range of −40°C to +105°C.ApplicationsIndustrial Process Control4 mA to 20 mA loop-powered transmittersSmart transmittersHART network connectivity
