- New 4-to-20 mA 16-bit digital-to-analog converter for smart transmitters integrates precision converter with power management circuitry to simplify design and boost available power.
AD5421, a precision 16-bit DAC with on-board power management circuitry

Norwood, MA (05/25/2010) - Analog Devices, Inc. (NYSE: ADI), the leading provider of data conversion technology, today introduced a precision 16-bit DAC (digital-to-analog converter) with on-board power management circuitry designed for loop-powered, smart transmitter applications used in industrial equipment. The new DAC drives system efficiency by reducing total component count and internal power consumption to allow greater functionality at the remote site. Smart transmitters are intelligent microprocessor-based field instruments that monitor process control variables, including temperature, mass flow rate, and pressure. Smart transmitters are typically located in hazardous or remote areas and enable two-way communication via the 4-to-20 mA analog loop by using additional communication protocols. Power consumption is a primary consideration when selecting electronic circuitry for smart transmitter designs because these field instruments must be powered directly from the 4-to-20 mA loop due to their location.

ADI’s AD5421 DAC is a complete, loop powered, digital to 4-to-20 mA transmitter that consumes 50 percent less power and offers a 55 percent footprint saving over competing offerings. Incorporating programmable voltage regulation circuitry, the AD5421 generates the low-voltage supply required to power the peripheral components within the smart transmitter. By conserving the system power budget, the AD5421 DAC enables system engineers to select more accurate, higher-power sensor electronics or include supplementary functionality, such as extra communication protocols to enhance network connectivity and display screens to improve system interfacing. The new DAC offers three times more accuracy than competitive products, and provides on-chip diagnostics that increase system uptime of process control systems located in large plants, such as oil refineries. The high linearity and low drift performance offered by the AD5421 DAC eliminate the need for multiple, costly calibration routines required by traditional discrete solutions to obtain high-end system performance specifications. Watch the AD5421 DAC video for more information on its features.

“The low power consumption and intelligent power management circuitry of the AD5421 DAC preserve the system power budget and enable the development of high-performance, feature-rich smart transmitters,” said Donal Geraghty, product line director, Converter Group, Analog Devices. “The new DAC meets the productivity demands of the process control industry by improving the accuracy and repeatability of smart transmitters operating in harsh factory environments.”

About the AD5421 16-Bit DAC
The AD5421 includes a voltage regulator, which is commonly used to power itself and other devices in the smart transmitter. The regulator provides a programmable 1.8-V to 12-V output voltage. The device also contains precision 1.25-V and 2.5-V references, eliminating the need for a discrete regulator and voltage reference. Consuming only 250 µA of quiescent current, the AD5421 offers 0.05 percent maximum TUE (Total Unadjusted Error) and 5 ppm (parts per million) drift performance. The AD5421 can be used with standard HART (Highway Addressable Remote Transducer) protocol circuitry and offers NAMUR compliant output ranges. The device is specified over the extended industrial temperature range of –40°C to +105°C and incorporates a standard SPI (serial peripheral interface) compatible interface.

Recommended Complementary Components
Complementary components for the AD5421 include the ADuM140x iCoupler digital isolators, ADuC7060 and ADuC7061 microcontrollers, and AD7790 and AD7791 sigma-delta ADCs (analog-to-digital converters).

Pricing and Availability

Product Sample
Price Each
per 1,000
AD5421 Now $4.52 9.7 mm × 4.4 mm 28-lead TSSOP
(thin-shrink small-outline package)

5 mm × 5 mm 32-lead LFCSP
(lead frame chip scale package)
For more information, visit For information on ADI’s DAC products, visit

Industry’s Leading Converter Portfolio
More designers turn to Analog Devices than any other supplier for the high-performance conversion technology required to bridge the analog and digital worlds in today’s myriad electronic systems. With the industry’s leading portfolio of analog-to-digital converters and digital-to-analog converters, Analog Devices’ converter products feature the right combination of sampling rates, accuracy and reduced noise, power dissipation, price and package size required in industrial and instrumentation, healthcare equipment, automotive systems, communications infrastructure, and consumer electronics. Evaluation tools help customers quickly validate, select, and design in the optimal data converters to reduce design complexity, development schedules, and bill-of-material costs.

About Analog Devices

Innovation, performance, and excellence are the cultural pillars on which Analog Devices has built one of the longest standing, highest growth companies within the technology sector. Acknowledged industry-wide as the world leader in data conversion and signal conditioning technology, Analog Devices serves over 100,000 customers, representing virtually all types of electronic equipment. Analog Devices is headquartered in Norwood, Massachusetts, with design and manufacturing facilities throughout the world. Analog Devices is included in the S&P 500 Index.

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Linda Kincaid

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