EVAL-CN0518-EBZ

USB-Powered, 915 MHz RF Low Noise Amplifier Receiver with Overpower Protection Circuit

Overview

The EVAL-CN0518-EBZ is a USB-powered, RF power amplifier that is optimized for receiving signal chains in the 915 MHz ISM band. Using two HMC376 amplifiers cascaded together, the design provides a gain of 25dB and return losses of more than 10dB at its center frequency.

The circuit includes a high speed overpower cutoff that protects sensitive downstream equipment connected to the receiver system. The receiver system also automatically returns to normal operation when the RF power level drops within the acceptable range.

Designed to be used with the ADALM-PLUTO, the EVAL-CN0518-EBZ features a small form factor with dimensions of 25.4mm×49.6mmx1.5748mm (PCB only). The RF input and output are designed with a 50Ω impedance, enabling direct connection between the circuit and standard 50Ω systems.

A micro-USB connector is used for the input power, allowing the evaluation board to use most 5V wall wart power supplies available in the market.

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/eval-cn0518-ebz.jpg — Figure 1 EVAL-CN0518-EBZ Reference Design Board

The EVAL-CN0518-EBZ features the HMC376, which is a GaAs, pHEMT, MMIC, low noise amplifier operating between 700MHz to 1000MHz. This amplifier is ideal for use in GSM and CDMA cellular base station front end receivers. This low noise amplifier does not require any external matching circuitry to operate.

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/block_diagram.png — Figure 2 EVAL-CN0518-EBZ Simplified Block Diagram

Reference Design Hardware

Primary Side

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/primary_side.png — Figure 3 CN0518 Primary Side

Secondary Side

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/secondary_side.png — Figure 4 CN0518 Secondary Side

SMA Connectors

The SMA connectors are used for the RF input and output connections.

RF Port	Reference Designator	Description
RF Input (SMA male connector)	J2	Connect to a radio or piece of RF equipment
RF Output (SMA female connector)	J1	Connect to an antenna

LED Indicators

The reference design uses two LEDs to indicate its current status:

RF Port	Reference Designator	Description
Green LED	DS1	Indicates that power is present on the board
Red LED	DS2	Indicates when an overpower event occurs

This table shows the board status when the various LEDs are ON/OFF.

Green LED	Red LED	Board Status
OFF	OFF	No Power
ON	OFF	Normal RF Operation
ON	ON	Overpower Event (RF Output Attenuated)

Power Supply Connector

P1 is the micro-USB port used to provide 5V power to the board.

Getting Started

Required Equipment

Hardware

EVAL-CN0518-EBZ
ADALM-PLUTO
Two (2) micro-USB power adaptor or micro-USB to USB cable for powering ADALM-PLUTO and EVAL-CN0518-EBZ
One (1) SMA male-to-male cable

Firmware

For the step-by-step procedure on how to update the Pluto Firmware, you can use this user guide link.

The latest firmware version for the ADALM-PLUTO can be found here:

Download

ADALM-PLUTO Firmware: Pluto version latest release

ADALM-PLUTO Preparation

Follow the step-by-step process on how to configure the ADALM-PLUTO for proper operation by referring to this link.

Test Setup

Connect directly the Rx port of ADALM-PLUTO to J1 of the EVAL-CN0518-EBZ.
Connect the Tx port of the ADALM-PLUTO to J2 of the EVAL-CN0518-EBZ using a male-to-male SMA cable.
Connect P1 (micro-USB) connector of the EVAL-CN0518-EBZ into a PC USB port or a 5V USB charger.
Connect the micro-USB to USB cable to a PC/laptop and the other end to the ADALM-PLUTO data port.
The DS2 LED of CN0518-EBZ will automatically turn on, indicating that the board is powered on and is in operation.

Important

The ADALM-PLUTO can be configured using an IIO Oscilloscope, visit the website on IIO Oscilloscope to learn more about the tool.

IIO Oscilloscope

Important

Make sure to download or update to the latest version of IIO Oscilloscope found on this link.

Once done with the installation or an update of the latest IIO Oscilloscope, open the application. The user needs to supply a URI, which will be used in the context creation of the IIO Oscilloscope. The instructions can be seen in the previous section.
Press refresh to display available IIO devices. Once the ADALM-PLUTO appeared, press connect.

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/connecting_of_iio_osc.jpg — Figure 6 IIO Oscilloscope Configuration

On the AD936x tab, set the required parameters for the EVAL-CN0518-EBZ to operate properly.

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/ad936x.png — Figure 7 ADALM-PLUTO Settings

Using the capture window, you can see the RF output of the EVAL-CN0518-EBZ in the frequency domain.

https://media.githubusercontent.com/media/analogdevicesinc/documentation/main/docs/solutions/reference-designs/eval-cn0518-ebz/capture_window.png — Figure 8 CN0518 RF Output

Schematic, PCB Layout, Bill of Materials