RFM31B
2. Functional Description
HopeRF's RFM31B are highly integrated, low cost, 433/868/915MHz wireless ISM receivers module .
The wide operating voltage range of 1.8–3.6V and low current consumption
solution for battery powered applications.
makes the RFM31B an ideal
The RFM31B 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 high precision local oscillator (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 .
The RFM31B is designed to work with a microcontroller to create a very low
integrated on-chip which allows for a wide operating supply voltage range from
SPI bus is used to communicate with an external microcontroller. Three
are available. A complete list of the available GPIO functions is shown in "8.
cost system. Voltage regulators are
+1.8 to +3.6V. A standard 4-pin
configurable general purpose I/Os
Auxiliary Functions" and includes
microcontroller clock output, Antenna Diversity, Antenna Switch,POR, and various interrupts. A complete list
of the available GPIO functions is shown in "RFM31B Register Descriptions.”
X1
30 MHz
C3
C4
C5
1 u
VDD
GP1
GP2
100 p
100 n
VDD_RF
NC
SCLK
SDI
GP3
1
2
3
15
14
13
C1
GP4
GP5
Microcontroller
RFp
SDO
VDD_D
NC
RF31B
L1
RXn
NC
4
5
12
11
C2
C6
1 u
RFM31B module
VSS
,
Figure 1.RFM31B Application Example
Tel: +86-755-82973805 Fax: +86-755-82973550 E-mail: sales@hoperf.com http://www.hoperf.com
10
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