RFM42B/43B
2. Functional Description
HopeRF's RFM42B/43B are highly integrated,low cost,433/868/915MHz wireless ISM transmitters module .
The wide operating voltage range of 1.8–3.6V and low current consumption makes
the RFM42B/43B
an ideal solution for battery powered applications.
The RF carrier is generated by an integrated VCO and Fractional-N PLL synthesizer. The synthesizer is
designed to support configurable data rates, output frequency, frequency deviation, and Gaussian filtering at
433MHz, 868MHz, 915MHz band. The transmitFSK data is modulated directly into the data stream and can be
shaped by a Gaussian low-pass filter to reduce unwanted spectral content.
The RFM42B’s PA output power can be configured betwee+n1 and +20dBm in 3dB steps, while the RFM43B's
PA output power can be configured between –8 and +13 dBm in 3dB steps.
ramp-up and ramp-down control to reduce unwanted spectral spreading.
The PA incorporates automatic
The RFM42B/43B is designed to work with a microcontroller to create a
very low cost system. Voltage
regulators are integrated on-chip which allows for a wide operating supply voltage
A standard 4-pin SPI bus is used to communicate with an external microcontroller.
range from +1.8 to +3.6V.
Three configurable general purpose I/Os are available. A complete list of the available GPIO functions is available
in “ RFM42B/43B Register Descriptions.”
2.1. Operating Modes
The RFM42B/43B provides several operating modes which can be used to optimize the power consumption for
a given application.
Table8 summarizes the operating modes of the RFM42B/43B. In general, any given operating mode may be
classified as an active mode or a power saving mode. The table indicates which block(s) are enabled (active) in
each corresponding mode. With the exception of the SHUTDOWN mode, all can be dynamically selected by
sending the appropriate commands over the SPI. An “X” in any cell means that, in the given mode of operation,
that block can be independently programmed to be either ON or OFF, without noticeably impacting the current
consumption. The SPI circuit block includes the SPI interface hardware and the device register space. The 32 kHz
OSC block includes the 32.768 kHz RC oscillator or 32.768 kHz crystal oscillator and wake-up timer. AUX
(Auxiliary Blocks) includes the temperature sensor, general purpose ADC, and low-battery detector.
Table 8. Operating Modes
Mode Name
Circuit Blocks
Digital LDO
SPI
32 kHz OSC AUX
30 MHz
XTAL
PLL
PA
I
VDD
SHUTDOWN
OFF
(Register contents
lost)
OFF
OFF
OFF
OFF
OFF
OFF
15 nA
STANDBY
SLEEP
ON
ON
ON
ON
ON
ON
ON
OFF
ON
X
OFF
X
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
OFF 450 nA
(Register contents
retained)
OFF
OFF
1 µA
1 µA
SENSOR
READY
ON
X
X
OFF 800 µA
OFF 8.5 mA
TUNING
TRANSMIT
X
X
ON
X
X
ON
ON
ON
30 mA*
*Note: Using RFM43B at +13dBm using recommended reference design.
Tel: +86-755-82973805 Fax: +86-755-82973550 E-mail: sales@hoperf.com http://www.hoperf.com
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