RFM22B/23B
2. Functional Description
HopeRF's RFM22B/23B are highly integrated,low cost,433/868/915MHz wireless ISM transceivers module .
The wide operating voltage range of 1.8–3.6 V and low current consumption
makes theRFM22B/23B
an ideal solution for battery powered applications.
The RFM22B/23B operates as a time division duplexing (TDD) transceiver where the device alternately transmits
and receives data packets. The device uses a single-conversion mixer to downconvert the 2-level FSK/GFSK/OOK
modulated receive signal to a low IF frequency. Following a programmable gain amplifier (PGA) the signal is
converted to the digital domain by a high performance ADC allowing filtering, demodulation, slicing, and packet
handling to be performed in the built-in DSP increasing the receiver’s performance and flexibility versus analog
based architectures. The demodulated signal is then output to the system MCU through a programmable GPIO or
via the standard SPI bus by reading the 64-byte RX FIFO.
A single high precision local oscillator (LO) is used for both transmit and receive modes since the transmitter and
receiver do not operate at the same time. The LO is generated by an integrated VCO and Fractional-N PLL
synthesizer. The synthesizer is designed to support configurable data rates, output frequency and frequency
deviation at 433MHz,868MHz,915MHz band. The transmit FSK data is modulated directly into the data
stream and can be shaped by a Gaussian low-pass filter to reduce unwanted spectral content.
The RFM22B’s PA output power can be configured between +1 and +20 dBm in 3 dB steps, while the RFM23B's
PA output power can be configured between –8 and +13 dBm in 3 dB steps.
The RFM22B/23B supports
frequency hopping, TX/RX switch control, and antenna diversity switch control to extend the link range and
improve performance
very low cost system as shown
The RFM22B/23B is designed to work with a microcontroller to create a
tors are integrated on-chip which allows for a wide
from +1.8 to +3.6 V. A standard 4-pin SPI bus is used to communicate with an
configurable general purpose I/Os are available. A complete list of the available
operating supply voltage range
external microcontroller. Three
GPIO functions is shown in
Figure 1. Voltage regula
"8. Auxiliary Functions"and includes microcontroller clock output, Antenna Diversity, POR, and various interrupts.
Tel: +86-755-82973805 Fax: +86-755-82973550 E-mail: sales@hoperf.com http://www.hoperf.com
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