RFM31B
2.1. Operating Modes
The RFM31B provides several operating modes which can beused to optimize the power consumption for a given
application. Depending upon the system communication protocol, an optimal trade-off between the radio wake time
and power consumption can be achieved.
Table8 summarizes the operating modes of the RFM31B. 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 operating mode. 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
RX
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
ON 18.5 mA
TUNING
RECEIVE
X
X
ON
X
X
ON
ON
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