Circuit Note CN-0202 Devices Connected/Referenced Industrial Current/Voltage Output Driver AD5750 Circuits from the Lab reference circuits are engineered and with Programmable Ranges tested for quick and easy system integration to help solve todays 16-Bit nanoDAC Digital-to-Analog analog, mixed-signal, and RF design challenges. For more AD5662 Converter in SOT-23 information and/or support, visit www.analog.com/CN0202. Ultralow Noise, 4.096V LDO XFET Voltage ADR444 Reference with Current Sink and Source Flexible, High Accuracy, Low Drift, PLC/DCS Analog Output Module low drift (3 ppm/C maximum for B-grade ), high initial EVALUATION AND DESIGN SUPPORT accuracy (0.04% maximum for B-grade), and low noise Circuit Evaluation Boards (1.8 V p-p typical, 0.1 Hz to 10 Hz) provides the reference CN-0202 Circuit Evaluation Board (EVAL-CN0202-SDPZ) voltage for both the AD5750 and AD5662 and guarantees System Demonstration Platform (EVAL-SDP-CB1Z) ultralow noise, high accuracy, and low temperature drift for the Design and Integration Files Schematics, Layout Files, Bill of Materials circuit. This circuit provides all the typical voltage and current output ranges with 16-bit resolution and no missing codes, CIRCUIT FUNCTION AND BENEFITS 0.05% linearity, and less than 0.2% total output error. The circuit shown in Figure 1 provides a full function, flexible, The circuit also contains key features for industrial programmable analog output solution that meets most applications, such as on-chip output fault detection and requirements for programmable logic controller (PLC) and protection (short circuit, undervoltage output, open circuit distributed control system (DCS) applications. The AD5662 low current output, and overtemperature), CRC checking to power (0.75 mW 5 V), rail-to-rail output, 16-bit nanoDAC prevent packet error (PEC), and flexible power-up options, converter and the AD5750 industrial current/voltage output making it an ideal choice for robust industrial control systems. driver are well matched with respect to input and output voltage No external precision resistors or calibration routines ranges, as well as reference voltage requirements. The ADR444 +15V + 10F 0.1F ADR444 V V +5V IN OUT +4.096V 0.1F GND + 10F 0.1F +5V + 10F 0.1F V V REF DD SYNCA SYNC 0V TO 5V V FB 0V TO 10V DV V AV 0V TO +4.096V CC REF DD AD5662 SCLK SCLK V OUT V 5V, 10V IN V OUT 0V TO 6V SDIN SDIN SYNCB SYNC 0V TO 12V GND 6V, 12V SCLK SCLK AD5750 4mA TO 20mA SDIN SDIN 0mA TO 20mA I OUT 0mA TO 24mA AV SDO SDO GND SS 20mA, 24mA 15V 10F 0.1F + Figure 1. Basic Analog Output Circuit for Single Channel (Simplified Schematic, All Connections and Protection Circuits Not Shown) Rev.0 Circuits from the Lab circuits from Analog Devices have been designed and built by Analog Devices engineers. Standard engineering practices have been employed in the design and construction of each circuit, and their function and performance have been tested and verified in a lab environment at room temperature. However, you are solely responsible for testing the circuit and determining its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. suitability and applicability for your use and application. Accordingly, in no event shall Analog Devices Tel: 781.329.4700 www.analog.com be liable for direct, indirect, special, incidental, consequential or punitive damages due to any cause whatsoever connected to the use of any Circuits from the Lab circuits. (Continued on last page) Fax: 781.461.3113 2011 Analog Devices, Inc. All rights reserved. 09733-001CN-0202 Circuit Note are needed to maintain consistent performance in mass The circuit must be constructed on a multilayer PC board with production, thereby making it ideal for PLC or DCS modules. a large area ground plane. Proper layout, grounding, and decoupling techniques must be used to achieve optimum CIRCUIT DESCRIPTION performance (see Tutorial MT-031, Grounding Data Converters The AD5750/AD5750-1 are both single-channel, low cost, and Solving the Mystery ofAGN andDGND and Tutorial precision voltage/current output drivers developed to meet the MT-101, Decoupling Techniques). requirements of industrial process control applications. The Measurements voltage output range can be programmed for the standard Integral nonlinearity (INL), differential nonlinearity (DNL), output ranges for PLC and DCS applications: 0 V to 5 V, 0 V to 10 V, 5 V to +5 V, and 10 V to +10 V. A 20% overrange and output error are the most important specifications for PLC, DCS, and other process control systems. The AD5750 has setting is also provided for the standard ranges, giving the highly flexible and configurable output ranges that can be following options: 0 V to 6 V, 0 V to 12 V, 6 V to +6 V, and tailored to meet the needs of the application. Measurements of 12 V to +12 V. INL, DNL, and output error for the circuit are shown in Figure 2, The current output, which is provided on a separate pin, can be Figure 3, and Figure 4, respectively. This data was taken at 25C programmed for the ranges of 4 mA to 20 mA, 0 mA to 20 mA, in the 0 V to 5 V voltage output mode. The test results for all the 20 mA to +20 mA, 0 mA to 24 mA, and 24 mA to +24 mA. other ranges are listed in Table 1. The unipolar ranges have a 2% overrange setting. Because the 4 AD5750/AD5750-1 current output can either source or sink 3 current, it can interface to a wide variety of sensors or actuators. The voltage and current output pins can be tied together to 2 configure the end system as a single-channel output if desired. 1 The AD5662 is a single channel, low cost, low power, rail-to-rail 0 voltage buffered output nanoDAC device. The AD5662 1 guarantees 1 LSB DNL under a wide range of reference 2 voltages that can vary from 0.75 V to the V supply so that the DD AD5750 and the AD5662 can operate from a common reference 3 source of 4.096 V, provided by the ADR444. The whole system 4 will benefit from the ultralow noise and low temperature 5 coefficient of ADR444. The ADR44x family of references are ideal for driving either the reference or the power input of 6 converters because they can source and sink current. The AD5662 also incorporates a power-on reset circuit to ensure DAC CODE that the DAC output powers up to either midscale or zero and Figure 2. INL for 0 V to 5 V Output Range remains there until a valid write takes place. 0.8 Devices for PLC and DCS applications generally need ESD protection and overvoltage protection much higher than the 0.6 formal recommend specifications. The AD5750 has integrated 0.4 ESD protection diodes internal to each pin that can prevent damage from a 3 kV transient (Human Body Model). However, 0.2 the industrial control environment can subject I/O circuits to 0 much higher transients. External 30 V, 600 W transient voltage suppressors (TVS), a 50 mA, 30 V PolySwitch, and power 0.2 Schottky diodes are built into the EVAL-CN0202-SDPZ circuit board to provide higher voltage ESD protection, 50 mA 0.4 overcurrent, and 30 V overvoltage protection. The optional 0.6 external protection circuits are not shown in the simplified schematic of Figure 1 but can be found in the detailed schematic 0.8 (EVAL-CN0202-SDPZ-SCH pdf file) in the CN0202 Design Support package: www.analog.com/CN0202-DesignSupport. DAC CODE Figure 3. DNL for 0 V to 5 V Output Range Rev. 0 Page 2 of 6 DNL (LSB) INL (LSB) 0 0 4096 4096 8192 8192 12288 12288 16384 16384 20480 20480 24576 24576 28672 28672 32768 32768 36864 36864 40960 40960 45056 45056 49152 49152 53248 53248 57344 57344 61440 61440 65536 65536 09735-003 09733-002