CN0337 Datasheet, PDF (6/8 Pages) Analog Devices – EVALUATION AND DESIGN SUPPORT

CN-0337
Circuit Note
COMMON VARIATIONS
The circuit is proven to work with good stability and accuracy
with component values shown. Other precision op-amps and
other ADCs can be used in this configuration to convert
resistance deviation input range to digital output and for other
various applications of the circuit.
the circuit’s performance. The EVAL-CN0337-PMDZ board
contains the circuit to be evaluated, as described in this note
and the SDP evaluation board is used with the CN0337
evaluation software to capture the data from the EVAL-
CN0337-PMDZ circuit board.
Equipment Needed
The circuit in Figure 1 can be redesigned for other than 0°C to
 PC with a USB port, Windows® XP, Windows Vista® (32-
300^oC input temperature ranges, following the recommendations
bit), or Windows® 7/8 (64- or 32-bit)
given in Circuit Design section. Table 1 shows calculations for
 EVAL-CN0337-PMDZ circuit evaluation board
some standard temperature ranges when using Pt100 RTD
sensors.
 EVAL-SDP-CB1Z SDP evaluation board
 SDP-PMD-IB1Z interposer board
Table 1. Resistor Values for Common Temperature Ranges¹
Temperature Range
R1
R2
R4, R12
−50°C to 50°C
79.4 Ω 7.82 kΩ 93.1 kΩ
0°C to 50°C
100 Ω
11.7 kΩ 237 kΩ
 CN0337 evaluation software
 Precision Resistance Decade Box or Pt100 sensor (the
calibration procedure can be performed if a resistance box
is not available)
0°C to 100°C
100 Ω
5.83 kΩ 118 kΩ
Getting Started
0°C to 200°C
0°C to 300°C
0°C to 400°C
0°C to 500°C
0°C to 600°C
0°C to 700°C
0°C to 800°C
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
100 Ω
2.91kΩ
1.91 kΩ
1.45 kΩ
1.17 kΩ
976 Ω
837 Ω
723 Ω
59 kΩ
39.2 kΩ
29.4 kΩ
23.7 kΩ
19.6 kΩ
16.9 kΩ
14.7 kΩ
Load the evaluation software by placing the CN0337 evaluation
software disc in the CD drive of the PC. You also can download
the most up to date copy of the evaluation software from
CN0337 evaluation software. Using the My Computer icon,
locate the drive that contains the evaluation software disc and
open the setup.exe file. Follow the on-screen prompts to finish
the installation. It is recommended to install all software
1 _{The values for the other resistors are as shown in Figure 1 (R5 = R6 = 2 kΩ,}
R3 = 1 kΩ, R8 = 26.7 kΩ, R9 = 1.1 kΩ
The AD7091 is similar to the AD7091R, but without the voltage
reference output, and the input range is equal to the power
supply voltage. The AD7091 can be used with a 2.5 V ADR391
components to the default locations.
Functional Block Diagram
A functional block diagram of the test setup is shown in Figure 4.
Setup
reference. The ADR391 does not require buffering.
1. Connect the EVAL-CFTL-6V-PWRZ (+6 V dc power
The ADR391 is a precision 2.5 V band gap voltage reference,
featuring low power and high precision (9 ppm/°C of temperature
drift) in a tiny TSOT package.
The AD8605 and AD8606 are single and dual versions of the
quad AD8608 and can be used as a substitute for the AD8608, if
different configurations are needed.
supply) to SDP-PMD-IB1Z interposer board via the de
barrel jack.
2. Connect the SDP-PMD-IB1Z (interposer board) to EVAL-
SDP-CB1Z (SDP board) via the 120-pin Connector A.
3. Connect the EVAL-SDP-CB1Z (SDP board) to the PC via
the USB cable.
4. Connect the EVAL-CN0337-PMDZ evaluation board to
The AD8601, AD8602, and AD8604 are single, dual, and quad
the SDP-PMD-IB1Z interposer board via the 12-pin
rail-to-rail, input and output, single-supply amplifiers featuring
header Pmod connector.
very low offset voltage and wide signal bandwidth, that can be
5. Connect the resistance decade box (Pt100 sensor) to the
used in place of AD8605, AD8606, and AD8608.
EVAL-CN0337-PMDZ evaluation board via the terminal
The AD7457 is a 12-bit, 100 kSPS, low power, SAR ADC, and
block J2.
can be used in combination with the ADR391 voltage reference
in place of AD7091R, when a 300 kSPS throughput rate is not
needed.
CIRCUIT EVALUATION AND TEST
Test
Launch the evaluation software. The software can communicate
to the SDP board if the Analog Devices System Development
Platform drivers are listed in the Device Manager. After USB
This circuit uses the EVAL-CN0337-PMDZ circuit board, the
SDP-PMD-IB1Z, and the EVAL-SDP-CB1Z system
demonstration platform (SDP) evaluation board. The SDP-
PMD-IB1Z interposer board and the EVAL-SDP-CB1Z SDP
board have 120-pin mating connectors. The interposer board
and the EVAL-CN0337-PMDZ board have 12-pin Pmod
communications are established, the SDP board can be used to
send, receive, and capture serial data from the EVAL-CN0337-
PMDZ board. Data can be saved in the computer for various
values of the input temperature (resistance). Information and
details regarding how to use the evaluation software for data
capturing can be found at CN0337 Software User Guide.
matching connectors, allowing quick setup and evaluation of
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