RH-128
Baseband Description and Troubleshooting
COMPANY CONFIDENTIAL
Copyright © 2009 Nokia. All rights reserved.
Issue 1
Page 5-10
MHz +/-2ppm. An integrated PLL and digital divider inside the CBP are used to create the required clock
for the system.
The SLEEP_CLK provides a 32.768 kHz +/-20ppm clock source to drive the CBP controller into sleep
mode. At this mode, most of the CBP is powered down and the TCXO is disabled.
Power Distribution
In normal operation, the baseband is powered by the mobile terminal‘s battery pack. The battery pack
consists of one lithium-ion cell with a capacity of 860 mA and safety and protection circuits
The PMU ACT5805 IC controls the power distribution for the whole mobile terminal, which includes the
baseband and the RF regulators, but excludes the RF power amplifier (RF PA) which drains power from
the battery directly. The battery provides power directly to the following parts of the system:
z
PMU ACT5805
z
RF PA
z
Vibrator
z
Keyboard & LCD backlights
z
Audio Amplifier
The heart of the power distribution is the power control block inside the PMU ACT5805. It includes all
the voltage regulators and feeds the power to the entire system. The PMU ACT5805 handles hardware
power-up functions so that the regulators are not powered on and the power up reset (NRST) is not
released if the battery voltage is less than 3.2V.
The baseband is powered by the following PMU ACT5805 regulators:
Regulator Voltage
Rating
Current Notes
VDD_DIG
3.00V
250mA
Always enabled except during power-off mode
VDD_CORE 1.80V 150mA
Enabled only when the system is powered on
(Off during sleep and power-off modes)
VDD_TXPLL
2.80V
80mA
Enabled only when the transmitter is on
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