Nokia 1508 Manual page 11

1508(RM-388)
Baseband Description and Troubleshooting
VDD_DIG 3V
VDD_CORE 1.8V
VDD_TXPLL 3.0V
VDD_TXXO 2.8V
KEYPAD_LED 2.8V
VDD_RX 2.85V
VDD_TX 2.85V
VDD_VIBE 3.0V
VC-TCXO
The CBP device integrates a phase-locked loop from the TCXO clock input.
The PMU optimizes TCXO operation that enables and disables appropriate circuits in
the proper sequence. The controller is enabled by the OSC_EN signal from the CBP.
When the selected transition occurs at OSC_EN, the controller quickly enables the
TCXO regulator and the input buffer, and begins counting SLEEP_CLK pulses.
Within an initial power on period, the TCXO will be stabilized to its own calibrated
frequency. This initial period, in units of 32.768 kHz clock pulses, is programmed into
a timer within the controller. When the timer expires, the output buffer is enabled. It
synchronizes with the TCXO input such that the TCXO_OUT signal is glitch free, only
valid TCXO pulses are output.
SLEEP Crystal Circuit for 32.768 kHz
The 32.768 kHz crystal oscillator is the primary SLEEP clock source when TCXO
Always enabled except during power-off
250mA
mode
Enabled only when the system is powered
150mA
on (Off during sleep and power-off modes)
80mA Enabled only when the transmitter is on
Enabled only when the system is powered
80mA
on (Off during sleep and power-off modes)
Enabled when the system is powered on, or
100mA
the keys are pressed, etc.
80mA Enabled when the receiver is on
150mA Enabled when the transmitter is on
Enabled only when the system is powered
150mA
on (Off during sleep and power-off modes)
Issue 1
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