DAC161P997 Single-Wire 16-bit DAC for 4- to 20-mA Loops

1 Features

• 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 Rreporting
• Programmable Output Current Error Level
• No External Precision Components
• Simple Interface to HART Modulator
• Small Package: WQFN-16 (4 x 4 mm, 0.5 mm Pitch)
• 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)

2 Application

• Two-Wire, 4-20 mA Current Loop Transmitter
• Industrial Process Control
• Actuator Control
• Factory Automation
• Building Automation
• Precision Instruments
• Data Acquisition Systems
• Test Systems

3 Description

The DAC161P997 is a 16-bit ∑Δ 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 (29 ppm/°C) and excellent long-term output current drift (90 ppmFS) while consuming less than 190 µA.

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 opto-couplers. 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 4-20 mA 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 WQFN package and is specified over the extended industrial temperature range of -40°C to 105°C.

1. For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Schematic

4 Revision History

Changes from F Revision (January 2013) to G Revision

• Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go
• Changed the second Thead to tbody/row and changed role to hdr in the Timing Requirements table Go
• Deleted the Related links subsection and checked for setting of single-part Go

Changes from E Revision (October 2013) to F Revision

• Changed O to Ω in tableGo

Changes from D Revision (March, 2013) to E Revision

• Changed application circuitGo

5 Pin Configuration and Functions

WQFN (RGH0016A)

16 pins

Top View

Pin Functions

PIN		DESCRIPTION	ESD PROTECTION
NAME	NO.
VA	15	Analog block positive supply rail
COMA	1	Analog block negative supply rail (local COMMMON)
COMD	2	Digital block negative supply rail (local COMMON)
VD	3	Digital block positive supply rail
DIN	4	SWIF input
DBACK	5	SWIF input loop back
ACKB	6	SWIF acknowledge output - open drain, active LOW
ERRLVL	8	Sets the output current level at power-up
LOW	10	Must be tied to COMA, COMD potential
C1	14	External capacitor
C2	13	External capacitor, HART Input
C3	12	External capacitor
BASE	16	External NPN base drive
N.C.	11	User must not connect to this pin
ERRB	7	Error flag output open drain, active LOW
OUT	9	Loop output current source
DAP	-	Die Attach Pad. For best thermal conductivity and best noise immunity DAP should be soldered to the PCB pad which is connected directly to circuit common node (COMA, COMD)	-