Si4010-C2
54
Rev. 1.0
18. Sleep Timer
The Si4010 includes a very low-power sleep timer that can be used to support the transmit duty cycle
requirements of the ETSI specification or self-wakeup for button independent applications. It consist of a
low speed (~2.1 kHz), very low power oscillator with a 24 bit down counter. When programmed to its maxi-
mum interval it takes ~2.1 hours to count down to zero. When it counts down to zero, it automatically pow-
ers down completely. The sleep timer can also be programmed to wake up the chip if the chip was
powered down. Control of the sleep timer is done with the API Sleep Timer Module functions.
19. Bandgap and LDO
Power management is provided on chip with LDO regulators for the internal analog and digital supplies, VA
and VD, respectively. The power-on reset circuit monitors the power applied to the chip and generates a
reset signal to set the chip into a known state. The bandgap produces voltage and current references for
the analog blocks in the chip and can be shut down when the analog blocks are not used. Control of the
bandgap and LDO is done with the System Module Function API vSys_BandGapLdo.
20. Low Leakage HVRAM
The low-leakage HVRAM provides 8 bytes of RAM memory which keeps its contents in all states including
standby mode as long as the supply voltage is applied to the chip. Control of the HVRAM is done with the
API HVRAM Module Functions.
21. Temperature Sensor
The on-chip temperature sensor measures the internal temperature of the chip and the temperature
demodulator converts the temperature sensors’ output into a binary number representing temperature and
is used to compensate the frequency of the LCOSC when the temperature changes. Temperature com-
pensation of the LCOSC is automatically taken care of by the Single Transmission Loop Module Function
API.
