ISM RX Click is a compact add-on board that contains a complete wireless RF digital data receiver. This board features the MAX1471, a low-power CMOS RF dual-channel receiver configurable through SPI serial interface from Analog Devices. It operates from both 3V or 5V and is designed to receive both amplitude-shift-keyed (ASK) and frequency-shift-keyed (FSK) data without reconfiguring the device or introducing any time delay generally associated with changing modulation schemes. Depending on signal power and component selection, this board supports a frequency of 433.92MHz. This Click board™ is suitable for remote low-speed communication, such as remote keyless access, garage or gate doors control, industrial control, home automation, and similar applications where this kind of communication is applicable.

ISM RX Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

ISM RX Click as its foundation uses the MAX1471, a low-power CMOS superheterodyne receiver for both ASK and FSK data without reconfiguration from Analog Devices. It includes all the active components such as a low-noise amplifier, an image-reject mixer, a fully integrated PLL, 10.7MHz IF limiting amplifier received-signal strength indicator, low-noise FM demodulator, and a 3V voltage regulator. The MAX1471 can achieve data rates as high as 33kbps using Manchester Code (66kbps nonreturn to zero) depending on signal power and component selection.

As already mentioned before, this Click board™ can receive both ASK and FSK data simultaneously. This feature of the MAX1471 can be achieved and selected with the switch labeled as DMOD SEL that allows the selection between ASK and FSK data. The MAX1471 receives binary FSK or ASK data on a frequency of 433.92MHz, which is set based on the used components. ASK modulation uses a difference in the carrier's amplitude to represent logic 0 and logic 1 data, while the FSK uses the difference in frequency of the carrier.

Differential peak-detecting data demodulators are available for both the FSK and ASK analog baseband data recovery. The MAX1471 consists of a discontinuous Receive mode for low-power operation, configured through a serial interface. This mode also allows self-polling, where the MAX1471 can stay in Sleep mode as long as eight minutes and wake the system MCU, offering additional power savings. On the consumption side, it draws less than 1.1µA in Shutdown and only 7mA in Receive mode.

ISM RX Click communicates with MCU using a standard SPI interface and possesses the SMA antenna connector with an impedance of 50Ω. This Click board™ can use it to connect the appropriate antenna.

This Click board™ operates only with a 5V logic voltage level from the mikroBUS™ socket. Still, the MAX1471 power supply offers the possibility of using both 3V, obtained by the NCP170 voltage regulator, and 5V logic voltage level selected via the HVIN SEL jumpers. Note that all the jumpers must be placed to the same side, or else the Click board™ may become unresponsive. 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: SPI
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V
• ISM RX Frequency Range: 433.92MHz
• RX Mode Current: 7mA
• Sensitivity (ASK/FSK): -114/-108 dBm
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +125°C

• Schematic
• MAX1471 Datasheet
• NCP170 Datasheet
• mikroSDK
• GitHub