DC2870A-KIT Analog Devices

DEMO MANUAL DC2870A LTC5596 Linduino Shield 100MHz to 40 GHz RMS Power Detector DESCRIPTION Demonstration circuit DC2870A is a Linduino shield for the shield by jumper JP1. Contact applications support Mean-Squared Power Detector LTC 5596. It is set up for for more information. quick evaluation of RMS RF power measurement using Design files for this circuit board are available. the Arduino/Linduino compatible platform and software download available here. When connected to PC with USB cable, accurate power level can be monitored using the graphic user interface. ABSOLUTE MAXIMUM INPUT RATINGS The LTC5596 is a wide dynamic range linear-in-dB Mean (Note 1) Squared RF Power Detector, operational from 100MHz to Supply Voltage(V ): +3.8V CC 40GHz. The Linduino (DC2026C) platform provides 10-bit DC Voltage at RF : 0.3V to 1.0V IN ADC at 4.9mV/LSB resolution with 5V default reference DC Voltage at FLTR: 0.3V to 0.4V voltage. Input dynamic range with 1dB accuracy is up DC Voltage at EN: 0.3V to 3.8V to 35dB depending on frequency. The detector output RF Input Power-Average: +15dBm IN slope is normally 6 LSB/dB. The DC2870A Demo Circuit T 150C JMAX is optimized for wide operational frequency signals up Case Operating Temperature Range 40C to 105C to 40GHz using the 2.9mm SMK edge mount connector. Storage Temperature Range 65C to 150C Input impedance is internally matched to 50. It is suit- able for RMS measurements of high crest factor wave- Note 1: Voltage on all pins must not exceed V +0.3V CC forms up to 12dB peak-to-average. No external coupling or be less than 0.3V. capacitor is necessary if DC voltage at RF pin is kept IN CAUTION: This part is sensitive to electrostatic discharge below 1.0V. On board 3.3V regulator provides power to (ESD). Observe proper ESD precautions when handling All registered trademarks and trademarks are the property of their respective owners. the LTC5596. TEST SETUP Figure1. Test Setup for RF Performance Measurements Rev. 0 1DEMO MANUAL DC2870A NOTES ON TEST EQUIPMENT AND SETUP n n Use a high performance signal generator with accu- Connecting cable for RF signal should be rated up to rate output power levels up to 40GHz, such as Rohde 40GHz for the best performance. Schwarz SMF100A. n Optional input attenuation can be used to improve n Demo Board DC2870A includes the SMK 2.9mm con- return loss, but also shifts the log intercept point nector for best performance up to 40GHz. accordingly. QUICK START PROCEDURE 1. Remove the DC2870A from its protective packaging 6. Connect USB cable from PC to Linduino board. Con- in an ESD-safe working area, connect USB cable to nect the RF input to the signal generator at the 2.92mm PC(see Figure1). connector 2. Set JP1 which provides the 3.3V to V by the on board 7. Set the frequency and power level (less than +10dBm) CC regulator. of the signal generator. 3. Go to www.analog.com, download and install QuikEval 8. Open LTC5596 GUI, and set the frequency of signal to if its not yet installed. be measured. Push READ to measure RF power. Us- ing the default calibration would be loading the nominal 4. The Eval Kit comes with a Linduino board pre-loaded slope and intercept from LTC5596 data sheet values. with firmware. Follow Figure2 to re-load the firmware See Figure3. if necessary, which can be downloaded from www. analog.com. 9. For higher accuracy, Calibration can be performed using the GUI at various frequency with two point calibration. 5. Download LTC5596 GUI, and install all necessary driv- Set input power level to the corresponding calibration ers onto PC from the LTC5596 product page. Follow points on the GUI, and calibrate accordingly by clicking instruction from QuikEval which will automatically the corresponding button. download the GUI. 10. Read RF power using the GUI. DEMO BOARD USAGE NOTES 1. Demo Board DC2870A has provisions for inter-stage 3. ADC count 4.9mV/slope+intercept=output power. filter cap. Additional capacitor (C3) can be added to Slope is derived from two point calibration in the linear slow down the transient response to reduce the output region of transfer function. ripple. The range for C3 is 10pF to 1nF. 4. A minimum two point calibration is necessary for most 2. Output power is calculated using slope and intercept. applications. Additional calibration points will improve the accuracy of the power detection. Rev. 0 2