User Guide

Mode Description
PWR_OFF In this mode (warm), the main battery is present and its voltage is over RETU master
reset threshold. All regulators are disabled, PurX is on low state, the RTC is on and the
oscillator is on. PWR_OFF (cold) mode is almost the same as PWR_OFF (warm), but the
RTC and the oscillator are off.
RESET RESET mode is a synonym for start-up sequence. In this mode certain regulators are
enabled and after they and RFClk have stabilized, the system reset (PurX) is released
and PWR_ON mode entered. RESET mode uses 32kHz clock to count the REST mode delay
(typically 16ms).
SLEEP SLEEP mode is entered only from PWR_ON mode with the aid of SW when the system’s
activity is low.
FLASHING FLASHING mode is for SW downloading.
Voltage limits
Parameter Description Value
VMSTR Master reset threshold (RETU) 2.2V (typ.)
VMSTR+ Threshold for charging, rising (TAHVO) 2.1V (typ.)
VMSTR- Threshold for charging, falling (TAHVO) 1.9V (typ.)
VCOFF+ Hardware cutoff (rising) 2.9V (typ.)
VCOFF- Hardware cutoff (falling) 2.6V (typ.)
SWCOFF SW cutoff limit ~3.2V
Power key
The system boots up when power key is pressed (adequate battery voltage, VBAT, present).
Power down can be initiated by pressing the power key again (the system is powered down with the aid of
SW).
Power distribution
Power supply components:
• RETU
• TAHVO
• BT LDO
• camera LDO and SMPS
• MicroSD LDO
• backlight SMPS
All the above are powered by the main battery voltage.
Battery voltage is also used on the RF side for power amplifiers (GSM PA) and for RF ASIC Ahne.
Discrete power supplies are used to generate 1.8V and 2.8V for the camera module, 2.85V for MicroSD card
and max. 18V for backlight LEDs.
The device supports both 1.8V/3V SIM cards which are powered by RETU / VSIM1. RETUs VSIM2 is not used.
USB accessories which needs power from the device are powered by TAHVO / VOUT.
RM-86
System Module Nokia Customer Care
Issue 1 COMPANY CONFIDENTIAL Page 9 –7
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