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CN0272 Software User Guide
Overview
CN0272 is a high-speed photodiode signal conditioning circuit with dark current compensation. The system converts current from a high-speed silicon PIN photodiode and drives the inputs of a 20 MSPS ADC. This combination of parts offers spectral sensitivity from 400 nm to 1050 nm with 49 nA of photocurrent sensitivity, a dynamic range of 91 dB and 2 MHz of bandwidth. The signal conditioning circuitry of the system consumes only 40 mA of current from the ±5 V supplies making this configuration suitable for portable high-speed high-resolution light intensity applications such as pulse oximetry.
Other suitable applications for this circuit would be as an analog opto-isolator. It can also be adapted to applications that require larger bandwidth and less resolution such as adaptive speed control systems.
This user guide will discuss how to use the evaluation software to collect data from the EVAL-CN0272-SDPZ Daughter Board
Required Equipment
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PC with the following Minimum Requirements
USB type A to
USB type mini-B cable
Light source between 400nm to 1050nm (not included in kit)
SMB Connector (not required)
General Setup
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The
EVAL-SDP-CB1Z SDP-B Board connects to the PC via the
USB cable.
Installing the Software
Extract the file
CN0272 SDP Eval Software.zip and open the file
setup.exe.<html><br><br></html>
NOTE: It is recommended that you install the CN0272 SDP Evaluation Software to the default directory path C:\Program Files\Analog Devices\CN0272\ and all National Instruments products to C:\Program Files\National Instruments\
<html><br><br><br><br><br></html>
Click
Next to view the installation review page<html><br><br></html>
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Click
Next to start the installation<html><br><br></html>
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Upon completion of the installation of the
CN0272 SDP Eval Software, the installer for the
ADI SDP Drivers will execute.<html><br><br></html>
NOTE: It is recommended that you close all other applications before clicking “Next”. This will make it possible to update relevant system files without having to reboot your computer.
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Press
“Next” to set the installation location for the
SDP Drivers.<html><br><br></html>
It is recommended that you install the drivers to the default directory path <html><br></html>C:\Program Files\Analog Devices\SDP\Drivers
<html><br><br></html>
Press
“Next” to install the
SDP Drivers and complete the installation of all software. Click
“Finish” when done.<html><br><br></html>
Connecting the Hardware
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Select the voltage bias of the photodiode.
Select the onboard -5V bias by populating
JP1 with a shorting jumper as depicted below<html><br><br></html>
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Select an external voltage bias by populatign
JP1 with a shorting jumper as depicted below.
NOTE: When using an external voltage to bias the photodiode, a SMB connector also must be connected to J2. The other end of this cable must connect to a voltage supply ≤ 15V.
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Connect a 6V supply to the Barrel Jack or the Screw Terminal on the CN0272 Board<html><br><br></html>
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Connect the
USB Cable to the SDP-B Board and the PC<html><br><br></html>
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Using the Evaluation Software
Software Control and Indicator Descriptions
SDP Connector Dropdown Menu
Connect to SDP-B Board Button
When this button is pressed, the SDP-B Board makes a
USB connection to the CN0272 Board. A connection to the SDP-B Board must be made to use the software. This button is also used in conjuction with the
SDP Connector Dropdown Menu.
Take Snapshot(s) Button
Save Snapshot(s) Button
When this button is pressed, the software will save a single “Snapshot” or a collection of “Snapshots” to a tab delimited
ASCII spreadsheet file.
Acquisition Mode Radio Buttons
Single Snapshot - When the software is in this mode, the SDP-B Board will collect a single “Snapshot” of data.
Multiple Snapshots - When the software is in this mode, the SDP-B Board will collect multiple “Snapshots” of data.
Conversions in Snapshot Numerical Control
This control determines the number of conversions in a single “Snapshot” of data.
The minimum value is 1 and the maximum value is 65,536.
Snapshots to Take Numerical Control
This control determines the number of “Snapshots” of data the SDP-B Board collects.
The minimum value is 1 and the maximum is 65,536
This control is only enabled in Multiple Snapshots Acquisition Mode.
Snapshot Delay (ms) Numerical Control
This control determines the delay (in milliseconds) between “Snapshots.”
The minimum value is 1 and the maximum value is 65,536
This control is only enabled in Multiple Snapshots Acquisition Mode.
Control Tabs
Photocurrent Results - Clicking this tab brings the Photocurrent Results graph to the front
Histogram Results - Clicking this tab brings the Histogram Results graph to the front
Configure - Clicking this tab brings the System Settings to the front
Graph Controls
Graph Units Radio Buttons
Snapshot Displayed Numerical Control/Indicator
This control determines the current “Snapshot” to display in the graph. When the value is changed, the graph is updated with the “Snapshot” specified.
This control also acts as an indicator of the current “Snapshot” displayed in the graph. For example, when the software is in the process of collecting multiple “Snapshots,” the indicator is incremented as the “Snapshots” are collected.
This control/indicator is only enabled in Multiple Snapshots Acquisition Mode.
System Status String Indicator
This indicator displays a message to the user detailing the current state of the software. In this case, the system is inactive and the user needs to make a
USB connection to the CN0272 Board. The software requests that the user “Connect to the SDP-B Board.”
System Status LED Indicator