National Semiconductor's Single-Wire 16-bit DAC for 4-to-20 mA Loops Simplifies Smart Transmitter Design

SANTA CLARA, Calif., Aug. 15, 2011 /PRNewswire/ -- National Semiconductor Corp. (NYSE: NSM) today introduced a 16-bit digital-to-analog converter (DAC) featuring a single-wire interface and 4-to-20 mA current loop drive that simplifies the design of smart transmitters used in industrial two-wire sensor systems. The highly integrated DAC161P997 reduces component count and cost in factory and building automation control systems by enabling the use of a single isolation component to cross the isolation boundary. For sensing and detecting applications where galvanic isolation is not required, National's DAC161P997 interfaces directly to a microcontroller.

The low-power DAC161P997 provides system designers an exceptional balance of accuracy, ease of use, performance and system cost. Its delta-sigma DAC offers 16-bit accuracy with a minimal temperature coefficient of 29 ppm and long-term output current drift of 90 ppm, while consuming less than 190 uA of supply current. The DAC161P997's loop drive interfaces to a highway addressable remote transducer (HART) modulator, allowing injection of FSK-modulated digital data into the 4-to-20 mA current loop. The DAC operates over the -40 degrees C to 125 degrees C extended industrial temperature range.

Key Features and Benefits of the DAC161P997

• Single-wire interface: enables higher system accuracy compared to discrete PWM implementations, and lower system cost compared to 4-wire SPI solution
• Low power operation: 190 uA enables total system power consumption below 30 mW or 3.5 mA
• User programmable start up conditions and data rate auto detect: allows system configuration for trade-off between update-rate vs. power consumption
• Error detection and reporting: multiple error conditions detected automatically, providing higher system reliability

The DAC161P997 complements National's innovative Sensor AFE Family in smart transmitter designs, including a wide variety of gas, temperature and pressure sensor applications.

Pricing and Availability

Offered in a 16-pin, 4 mm by 4 mm LLP® package, the DAC161P997 is available now and priced at $4 in 1,000-unit quantities. For more information or to order samples and an evaluation board, visit http://www.national.com/pf/DA/DAC161P997.html.

About National Semiconductor

National Semiconductor is a leader in power management technology. Known for its easy-to-use analog integrated circuits and world-class supply chain, National's high-performance analog products enable its customers' systems to be more energy efficient. Headquartered in Santa Clara, Calif., National reported sales of $1.52 billion for fiscal 2011. Additional information is available at www.national.com.

National Semiconductor and LLP are registered trademarks of National Semiconductor Corporation. All other trademarks are the property of their respective owners.

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SOURCE National Semiconductor Corp.