S i 4 4 3 0
20
Preliminary Rev. 0.4
3.2. Operating Mode Control
There are four primary states in the Si4430 radio state machine: SHUTDOWN, IDLE, TX, and RX (see Figure 6).
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. The TX
and RX state may be reached automatically from any of the IDLE states by setting the txon/rxon bits in "Register
07h. Operating Mode and Function Control 1". Table 11 shows each of the operating modes with the time required
to reach either RX or TX mode as well as the current consumption of each mode.
The output of the LPLDO 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 digital modem, crystal oscillator, and 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.
Figure 6. State Machine Diagram
Table 11. Operating Modes
State/Mode
xtal
pll
wt
LBD or
TS
Response Time to
Current in State /Mode
[µA]
TX
RX
Shut Down State
X
X
X
X
16.21 ms
16.21 ms
10 nA
Idle States:
Standby Mode
Sleep Mode
Sensor Mode
Ready Mode
Tune Mode
0
0
0
1
1
0
0
0
0
1
0
1
X
X
X
0
0
1
X
X
1.21 ms
210 µs
200 µs
1.21 ms
210 µs
200 µs
400 nA
800 nA
1 µA
600 µA
9.5 mA
TX State
1
1
X
X
NA
200 µs
28 mA @ +13 dBm
RX State
1
1
X
X
200 µs
NA
18.5 mA
SHUT DWN
IDLE*
TX
RX
*Five Different Options for IDLE
