Si4430/31/32-B1
2.1. Operating Modes
The Si4430/31/32 provides several operating modes which can be used 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.
Table 9 summarizes the operating modes of the Si4430/31/32. 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 9. Operating Modes
Mode
Name
Circuit Blocks
32 kHz OSC AUX
Digital LDO
SPI
30 MHz
XTAL
PLL
PA
RX
I
VDD
SHUT-
DOWN
OFF (Register
contents lost)
OFF
OFF
OFF
OFF
OFF
OFF
OFF
15 nA
STANDBY ON (Register
contents
ON
ON
ON
ON
ON
ON
ON
OFF
ON
X
OFF
X
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
450 nA
1 µA
SLEEP
retained)
SENSOR
READY
ON
X
1 µA
X
800 µA
8.5 mA
TUNING
X
X
ON
TRANSMIT
RECEIVE
X
X
ON
ON
OFF 30 mA*
ON 18.5 mA
X
X
ON
ON
OFF
*Note: Using Si4430/31 at +13 dBm using recommended reference design.
Rev 1.0
17
IBM [ IBM ]
