RFM42B Datasheet, PDF (13/51 Pages) List of Unclassifed Manufacturers – ISM TRANSMITTER

RFM42B/43B
3.2. Operating Mode Control
There are three primary states in the RFM42B/43B radio state machine: SHUTDOWN, IDLE, and TX (see
Figure 5). The SHUTDOWN state completely shuts down the radio to minimize current consumption. There are five
different configurations/options for the IDLE state which can be selected to optimize the chip to the applications
needs. "Register 07h. Operating Mode and Function Control 1" controls which operating mode/state is selected
with the exception of SHUTDOWN which is controlled by SDN pin. The TX state may be reached automatically
from any of the IDLE states by setting the txon bit in "Register 07h. Operating Mode and Function Control 1."
Table 10 shows each of the operating modes with the time required to reach TX mode as well as the current
consumption of each mode.
The RFM42B/43B includes a low-power digital regulated supply (LPLDO) which is internally connected in parallel
to the output of the main digital regulator (and is available externally at the VR_DIG pin). This common digital
supply voltage is connected to all digital circuit blocks including the SPI and register space. The LPLDO has
extremely low quiescent current consumption but limited current supply capability; it is used only in the IDLE-
STANDBY and IDLE-SLEEP modes. The main digital regulator is automatically enabled in all other modes.
SSHHUUTTDDOWWNN
IDLE*
TX
*Five Different Options for IDLE
Figure 5. State Machine Diagram
Table 10. Operating Modes Response Time
State/Mode
Shut Down State
Idle States:
Standby Mode
Sleep Mode
Sensor Mode
Ready Mode
Tune Mode
TX State
Response Time to TX
16.8 ms
Current in State/Mode [µA]
15 nA
800 µs
800 µs
800 µs
200 µs
200 µs
NA
450 nA
1 µA
1 µA
800 µA
8.5 mA
RFM42B:
85 mA @ +20 dBm,
RFM43B:
30 mA @ +13 dBm
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