RF Meter 3 Click is a compact add-on board that collects information, analyzes RF power, and displays information in an easy-to-read digital format. This board features the LT5581, a low-power monolithic precision RMS power detector from Analog Devices. The RMS detector uses a proprietary technique to accurately measure the RF power in a range from 2GHz up to 2.6GHz, well-suited for signals with high crest factors. It outputs a DC voltage in linear scale proportional to an RF input signal power in dBm. This Click board™ is suitable for precision power measurement and control for various RF standards, including GSM/EDGE, CDMA, CDMA2000, W-CDMA, TD-SCDMA, UMTS, LTE, and WiMAX.

RF Meter 3 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

RF Meter 3 Click as its foundation uses the LT5581, RMS power detector with a 40dB dynamic range from Analog Devices. Users can use an RF power meter like this one to measure and document pulsed RF signals, noise-like signals, and pseudorandom signals. The RMS detector uses a proprietary technique to measure the RF power from 2GHz up to 2.6GHz accurately. Moreover, the LT5581 offers exceptional accuracy over its operating temperature range of -40°C to 85°C.

Its RMS measurement capability provides accurate RF power readings to within ±0.2dB regardless of waveforms with high crest-factor modulated content, multi-carrier or multitone. The LT5581 combines a proprietary high-speed power measurement subsystem with an internal 150kHz low pass averaging filter and an output voltage buffer in a completely integrated solution to achieve an accurate average power measurement of the high crest factor modulated RF signals. The resulting output voltage is directly proportional to the average RF input power in dBm.

This Click board™ uses two mikroBUS™ pins for direct control. The Enable pin, labeled as EN and routed to the CS pin of the mikroBUS™ socket, optimizes power consumption and is used for power ON/OFF purposes (Shutdown feature). When its Enable input pin is pulled low, the LT5581 draws a typical shutdown current of 0.2uA and a maximum of 6uA. As mentioned before, the resulting output voltage of the LT5581 is sent directly to an analog pin of the mikroBUS™ socket labeled as AN for MCU to read further and analyze RF signal data.

This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.

• Interface: Analog
• Compatibility: mikroBUS™
• Dimensions: 28.6 x 25.4mm
• Input Voltage: 3.3V or 5V
• Operating Frequency Range: Min. 2GHz, Max. 2.6GHz
• Dynamic Range: 40dB
• Accuracy: ±1dB
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C

• Schematic
• LT5581 Datasheet
• mikroSDK
• GitHub