The EVAL-ADL5902-ARDZ shield illustrates the functionality of the ADL5902, a 50 MHz to 9 GHz 65 dB TruPwr™ RMS responding RF power detector. The voltage outputs of the ADL5902 are routed to the ANALOG IN connector of the Arduino base board. This allows the RF power detector’s output voltage to be easily digitized and processed by the Arduino base board’s integrated six-channel ADC. The output of the ADL5902’s on-board temperature sensor is also routed to one of the ANALOG IN pins.

The power supply for the board comes from the Arduino base board through the POWER connector (5V). So while there is no need to connect an external power supply, the board can be powered by an external supply (6 Volt wall wart on P3 or 6V connected to the P1 screw terminals.

The EVAL-ADL5902-ARDZ is designed to work as a shield for EVAL-ADICUP3029 and DC2026C(also called Linduino One). For EVAL-ADICUP3029 , a PC software GUI application (EVAL-ADICUP3029) is available. Using this, the user can make RF power measurements and also calibrate the device to decrease measurement error. Device development drivers for EVAL-ADICUP3029 are also available, which the user may use to develop their own code for RF measurement, device calibration, and more.

• Input Frequency Range: 50MHz to 9GHz
• RF Input Range: 65dB (+3 dBm to -62 dBm)
• Maximum RF Input Power (Abs Max Rating): 21dBm
• Supply:
  1. 5V Internal from Arduino base board (short pin1 and pin2 of P4)
  2. 6V External (for operation with an external supply or operation without Arduino base board)
     1. 6V External supply (short pin1 and pin2 of P2; short pin2 and pin3 of P4)
     2. 6V Wall wart supply (short pin2 and pin3 of P2; short pin2 and pin3 of P4)
• Quiescent Current: < 100mA
• Input signal characteristic: CW or modulated carriers with large crest factors (e.g. QAM, XCDMA, OFDM, LTE)
• Recommended Calibration: 3-point
• Output Voltage Range:
  1. VOUT: ~0.175V to ~2.45V
  2. VTEMP: 1.1V to 1.8V

Choose among the power option to Power up the EVAL-ADL5902-ARDZ by shorting the correct pins using the provided shorting jumper caps.

1. Connect pin1 and pin2 of pin header P4.
   
2. Mount EVAL-ADL5902-ARDZ to EVAL-ADICUP3029 or Linduino One.
   

1. Connect pin2 and pin3 of pin header P4
   
2. Connect pin1 and pin2 of pin header P2
   
3. Connect 6V to the EVAL-ADL5902-ARDZ via the Screw terminal block
   

1. Connect pin2 and pin3 of pin header P4
   
2. Connect pin2 and pin3 of pin header P2
   
3. Connect 6V wall wart to the EVAL-ADL5902-ARDZ via the DC Jack
   

1. Set up EVAL-ADICUP3029 serial driver as in 1. Install mBed windows serial driver...
2. Download the software on the product page or click here.
3. Extract the Software GUI.zip to your computer.
4. Connect the EVAL-ADICUP3029 board using micro USB cable.
5. Set the S2 switch to USB.
   
6. In the extracted files look for power_detector-firmware.hex then copy the hex file to Computer»DAPLINK drive
   
   

   After loading the hex file to the DAPLINK drive the window explorer must automatically close or else you need to load the hex file to the drive again.

   
   

7. After the windows explorer automatically closes, reset the EVAL-ADICUP3029 board by pressing the S1 (reset) button on the board.
8. Go to extracted files and look for power_detector.exe file and double click to run the software. The Connection Window will open.
   

1. Mount EVAL-ADL5902-ARDZ to the EVAL-ADICUP3029 and connect EVAL-ADICUP3029 to computer as in Typical Hardware Setup for Measurement
2. Click the refresh button on Port Name to Identify the port where an EVAL-ADICUP3029 is installed
   

   If there is more than one EVAL-ADICUP3029 installed, select the port where EVAL-ADICUP3029 and EVAL-ADL5902-ARDZ connected
3. Set Baudrate to 115200
4. Select Auto-detect on Shield type.
5. Click Connect. The Measurement Window should Open.
   

The EVAL-ADL5902-ARDZ shield converts the measured ADC code to RF input power in dBm using stored calibration coefficients. A 3-point calibration methodology is used. The software program includes default calibration coefficients that correspond to the default response of the ADL5902 across RF power level and frequency. datasheet specifications of ADL5902. Because of part-to-part device variation, observed accuracy using the default calibration coefficients will be sub-optimal. By availing of the software program's 3-point calibration function, measurement accuracy can be increased.

Related topic: Calibration of EVAL-ADL5902-ARDZ

• Check the box to use default calibration coefficients
• Uncheck to use user calibration coefficients

1. Enter the frequency of the input RF signal
2. Uncheck Continuous Measurement
3. Click Measure Button

1. Enter the frequency of the input RF signal
2. Check Continuous Measurement
3. Click Measure Button
4. Click Stop to stop measuring at the last measurement

Click “Connection” or “Calibration” to switch to respective window.

1. Select the frequency using the frequency pull-down menu
2. Input an RF signal of 0dBm at the selected frequency. Click the Measure button beside 0dBm.
3. Input an RF signal of -45dBm at the selected frequency. Click the Measure button beside -45dBm.
4. Input an RF signal of -60dBm at the selected frequency. Click the Measure button beside -60dBm.
5. Click the Calibrate button. Console Log will indicate “User calibration coefficient for (frequency used) is updated.”
   

Calibration can be implemented using 2, 3 or 4-point calibration techniques which are used to approximate the transfer function of the ADL5902. Because the response of the ADL5902 changes with frequency, it is necessary to calibrate across frequency. If you are operating at a frequency that is in between two calibration frequencies, the software program will perform a weighted interpolation of the two sets of calibration coefficients.

The typical Vout vs. Pin characteristic of ADL5902 at 2.14GHz input is shown below (Figure 50 from the ADL5902 datasheet).

Two-point calibration is the simplest calibration technique. This models the transfer function of the ADL5902 and ADC as a single straight line

PIN = (CODE/SLOPE)+INTERCEPT

Where

PIN is the RF input power being measured

CODE is the ADC code

SLOPE is the slope of the ADL5902 transfer function's linear model (unit is LSBs/dB)

INTERCEPT is the (extrapolated) input RF power level which would yield and ADC code of 0 (this is a theoretical value with a unit of dBm)

SLOPE and INTERCEPT are calculated and stored during the calibration process by applying two known RF power levels, PIN1 and PIN2 (these RF power levels should be within the linear input range of the ADL5902) and measuring the corresponding ADC codes, CODE1 and CODE2. The equations for calculating SLOPE and INTERCEPT are as follows:

SLOPE = (CODE1–CODE2)/(PIN1−PIN2)

INTERCEPT = PIN1-(CODE1/SLOPE)

If there is some non-linearity in the transfer function of the RF detector, the number of calibration points can be increased to improve measurement accuracy. To implement three-point calibration, three known power levels are applied PIN1, PIN2 and PIN3 (PIN1 should be greater than PIN2 which should be greater than PIN3) and the corresponding ADC codes are noted (CODE1, CODE2, CODE3)

This results in two SLOPE values and two INTERCEPT values which are calculated using the equations

SLOPE1 = (CODE1–CODE2)/(PIN1−PIN2)

SLOPE2 = (CODE2–CODE3)/(PIN2−PIN3)

INTERCEPT1 = PIN1-(CODE1/SLOPE1)

INTERCEPT2 = PIN2-(CODE2/SLOPE2)

After calibration when measuring RF input power, the power is calculated using the appropriate equation

PIN = (CODE/SLOPE1)+INTERCEPT1   (if CODE > CODE2)

or

PIN = (CODE/SLOPE2)+INTERCEPT2   (if CODE < CODE2)

To decide which equation and calibration coefficients to use, the CODE from the ADC should be compared to CODE2 (CODE2 is the demarcation point between the two calibration regions). This will indicate which region of the ADL5902's transfer function the RF input power is located. For example, if the ADC CODE is greater than CODE2, this will indicate that the input power is greater than PIN2. So SLOPE1 and INTERCEPT1 should be used to calculate the input power. Because of the need to identify the region in which the measured RF input power is located, the CODE2 value should also be stored after calibration along with the SLOPE1, SLOPE2, INTERCEPT1 AND INTERCEPT2.

This technique can be extended to four or more calibration points. This may improve measurement accuracy at the cost of more complex calibration.

Development drivers are available for C and Python. Other development environments may be used but this development guided is focused on software development on CrossCore Embedded Studio (for C) and on Pycharm(for Python).

1. Download and install CrossCore Embedded Studio (CCES) 2.8.1
2. Download and install mBed windows serial driver

1. Install the following packs by following the How to install or upgrade Packs for CCES guide:
   • ARM.CMSIS.5.4.0
   • AnalogDevices.ADuCM302x_DFP.3.1.2
2. Switch back to C/C++ window and close CCES 2.8.1
3. Download power_detector_sample_c_code_and_header_files.zip and unzip it.
4. Run the “ADL5902 Sample C Code and Header Files.exe” and select “C:/Users/YourUsername/cces/2.8.1” as the destination folder. The adl5902 folder should appear in C:/Users/YourUsername/cces/2.8.1 .
   
   
5. Launch CCES 2.8.1 and select workspace C:/Users/YourUsername/cces/2.8.1. If the adl5902 has been installed elsewhere, choose that location as workspace. Switch to C/C++ window if it's not the current window.
   
   
6. To open the unzipped folder in the workspace, click File → Open Projects from File System. A new window will pop up and ask you to select the project or folder that you want to open. Select the proper directory then click Finish.
   
   

On the left side of the window, the structure of the loaded sample code should match the structure in the image shown below.

1. Setup Crosscore as in Setting Up CrossCore Embedded Studio
2. Connect your EVAL-ADICUP3029 and power up the RF power detector shield then click Build .
   
3. After it finishes building, click Debug and click Application with GDB and OpenOCD (Emulator). Copy the following Debug configurations on the new window that will appear then click the Debug button.
4. On the Debug window, click the Resume to run and display the results on the Console window.

Assumes a fresh installation of all required software

1. Download python 3.7.0 version. Choose the right version depending on operating system. For windows, choose Windows x86-64 executable installer. (Do not run installer yet)
2. Run installer as Administrator. During installation, check “Add Python 3.7 to PATH” before clicking “Install Now”
   
3. Install pyserial. For windows, enter pip3.7 install pyserial on command prompt.
4. Download and install any python IDE (eg. PyCharm community version)
5. Download and install mBed windows serial driver

1. Download power_detector_python_code_example.zip and unzip.
2. Install Power Detector Python Code Example.exe, the destination folder used is the “Scripts” directory where the python3.7 is located. For windows, the location path is similar to C:/Users/MyUsername/AppData/Local/Programs/Python/Python37/Scripts
   
3. Launch Python IDE and make sure to chose the python 3.7 as the interpreter.

1. Connect the EVAL-ADICUP3029 board using micro USB cable.
2. In the EVAL-ADICUP3029, set the S2 switch to USB.
3. Unzip power detector development code-release.zip from evaluation software
4. Find and copy power_detector-firmware.hex to the DAPLINK directory. Wait for the window to exit automatically.
5. Press S1 (reset) button on the EVAL-ADICUP3029 and mount the EVAL-ADL5902-ARDZ to the EVAL-ADICUP3029
6. On Python IDE, go to File»Open and browse for the /example code directory.
7. Click Project Tab located at left side of IDE and go to adl5902 folder and double click adl5902-getShieldReadings.py
8. Change the default Port number (“COM10”) in the example code. On your computer go to Control Panel»Device Manager look for Ports (COM & LPT) find the port number of “mbed Serial Port”.
9. Right click on any point in the working space and click Run ltc5596-getShieldReadings

For any queries regarding the hardware and evaluation software, contact us at EngineerZone.