CN0287 Datasheet, PDF (1/9 Pages) Analog Devices – Devices Connected

Circuit Note
CN-0287
Devices Connected/Referenced
AD7193
4-Channel, 4.8 kHz, Ultralow Noise,
24-Bit Sigma-Delta ADC with PGA
ADT7310
±0.5°C Accurate, 16-Bit Digital SPI
Temperature Sensor
AD8603
Circuits from the Lab® reference designs are engineered and
tested for quick and easy system integration to help solve today’s
analog, mixed-signal, and RF design challenges. For more
information and/or support, visit www.analog.com/CN0287.
ADR3440
ADG738
ADG702
Precision Micropower, Low Noise
CMOS R-to-R Input/Output
Operational Amplifiers
4.096 V, Micropower High Accuracy
Voltage Reference
CMOS, Low Voltage, 3-Wire Serially-
Controlled, Matrix Switch
CMOS Low Voltage 2 Ω SPST Switch
AD5201
ADuM1280
ADuM5401
33-Position Digital Potentiometer
3 kV RMS Dual Channel Digital
Isolators
Quad-Channel, 2.5 kV Isolators with
Integrated DC-to-DC Converter
Isolated 4-Channel, Thermocouple/RTD Temperature Measurement
System with 0.5°C Accuracy
EVALUATION AND DESIGN SUPPORT
Circuit Evaluation Boards
CN-0287 Circuit Evaluation Board (EVAL-CN0287-SDPZ)
System Demonstration Platform (EVAL-SDP-CB1Z)
Design and Integration Files
Schematics, Layout Files, Bill of Materials
CIRCUIT FUNCTION AND BENEFITS
The circuit shown in Figure 1 is a completely isolated 4-channel
temperature measurement circuit optimized for performance,
input flexibility, robustness, and low cost. It supports all types of
thermocouples with cold junction compensation and any type
of RTD (resistance temperature detector) with resistances up to
4 kΩ for 2-, 3-, or 4-wire connection configurations.
The RTD excitation current are is programmable for optimum
noise and linearity performance.
RTD measurements achieve 0.1°C accuracy (typical), and
Type-K thermocouple measurements achieve 0.05°C typical
accuracy because of the 16-bit ADT7310 digital temperature
sensor used for cold-junction compensation. The circuit uses a
four-channel AD7193 24-bit sigma-delta ADC with on-chip
PGA for high accuracy and low noise.
Input transient and overvoltage protection are provided by low
leakage transient voltage supressors (TVS) and Schottky diodes.
The SPI-compatible digital inputs and outputs are isolated
(2500 V rms), and the circuit is operated on a fully isolated
power supply.
Rev. C
Circuits from the Lab® reference designs 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 suitability and applicability for your use and application. Accordingly, in no event shall
Analog Devices 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)
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