NS’s DAC161P997 is a 16-bit Sigma-Delta digital-to-analog converter (DAC) used to send the analog output current of an industry-standard 4-20mA current loop, providing 16-bit precision, low temperature coefficient (29ppm/°C) output current And excellent long-term output current drift (90 ppmFS) performance, while power consumption is less than 190uA, mainly used for two-wire 4-20mA current loop transmitter, industrial process control, heater control, factory automation, building automation, precision Instrumentation, data acquisition system and test system. This article introduces the main features of DAC161P997, block diagram, various application block diagrams and application case circuit diagrams, DAC161P997EVAL evaluation board circuit diagram and component layout diagram.
Single-Wire 16-bit DAC for 4-20mA Loops
The DAC161P997 is a 16-bit ΣΔ digital-to-analog converter (DAC) for transmitting an analog output current over an industry standard 4-20 mA current loop. It offers 16-bit accuracy with a low output current temperature coefficient (29ppm/ °C) and excellent long-term output current drift (90 ppmFS) while consuming less than 190μA.
The data link to the DAC161P997 is a Single Wire Interface (SWIF) which allows sensor data to be transferred in digital format over an isolation boundary using a single isolation component. The DAC161P997’s digital input is compatible with standard isolation transformers and optocouplers. Error detection and Handshaking features within the SWIF protocol ensure error free communication across the isolation boundary.
For applications where isolation is not required, the DAC161P997 interfaces directly to a microcontroller.
The loop drive of the DAC161P997 interfaces to a HART (Highway Addressable Remote Transducer) modulator, allowing injection of FSK modulated digital data into the 4-20mA current loop. This combination of specifications and features makes the DAC161P997 ideal for 2- and 4-wire industrial transmitters.
The DAC161P997 is available in a 16–lead LLP package and is specified over the extended industrial temperature range of -40°C to 105°C.
Main features of DAC161P997:
■ 16-bit linearity
■ Single-Wire Interface (SWIF), with handshake
■ Digital Data transmission (no loss of fidelity)
■ Pin Programmable Power-Up Condition
■ Self adjusting to input data rate
■ Loop error detection and reporting
■ Programmable output current error level
■ No external precision components
■ Simple interface to HART modulator
■ Small package: LLP-16 (4×4 mm, 0.5 mm pitch) 4.0 Key Specifications
■ Output Current TempCo 29 ppmFS/°C(max)
■ Long-Term Output Current Drift 90 ppmFS(typ)
■ INL +3.3/−2.1 μA(max)
■ Total Supply Current 190 μA(max)
• Two-wire, 4-20 mA current loop transmitter
• Industrial Process Control
• Actuator control
• Factory Automation
• Building Automation
• Precision Instruments
• Data Acquisition Systems
• Test Systems
Figure 1. DAC161P997 block diagram
Figure 2. DAC161P997 Industrial 4-20mA Transmitter Block Diagram
Figure 3. DAC161P997 Loop-Powered Transmitter Block Diagram
Figure 4. DAC161P997 Self-Powered Transmitter Block Diagram
Figure 5. DAC161P997 Transmitter Block Diagram with Transformer-Coupled SWIF Link
Figure 5. Typical SWIF Link Block Diagram for DAC161P997
Figure 6. Main link block diagram without bidirectional I/O
Figure 7. SWIF Link Block Diagram Using Optocouplers
Figure 8. DAC161P997 Application Case Circuit Diagram
DAC161P997EVAL Evaluation Board
DAC161P997EVAL is the evaluation board for the DAC161P997 Single-Wire 16-bit DAC for 4-20mA Loops. This board will help the user evaluate the functionality and performance of the DAC161P997. It is also a demonstration tool for the DAC’s unique single wire interface ( SWIF).
DAC161P997EVAL combined with SPIO4 Sensor AFE Digital Controller Board the user can easily build a 4-20mA remote industrial transmitter where the PC host emulates a process sensor.
Figure 9. DAC161P997EVAL Evaluation Board Outline Drawing
Figure 10. DAC161P997EVAL Complete Evaluation System
Figure 11. DAC161P997EVAL Evaluation Board Circuit Diagram
Figure 12. DAC161P997EVAL Evaluation Board Component Layout
For details, see:
The Links: EL640.480-A3 V24C5H100BN