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
Generally, RX-34 EM architecture is implemented with three EM ASICs, EM ASIC D1420, EM ASIC N1310 and EM
ASIC N4200 controlling the EM and supplying the output voltages.
In addition to the ASIC, N5351 PM ASIC handles the power supply for HS USB controller.
In addition to EM ASIC D1420, EM ASIC N1310, PM ASIC N5351 and EM ASIC N4200 IC’s, RX-34 EM includes
functionalities to be powered using discrete regulator or direct battery voltage supply.
The following functionality will be supplied with discrete power supply (Low Dropout Linear Regulator, Iout
150 mA, typical Iq no load 80 uA, Vout 2.8V package 4-bump WLCSP, output noise 40 uV):
• LCD
• System clock oscillator
• Analog voltage supply for level shifters
Clocking scheme and controlling signals
There are two main clocks in the BB system: 19.2 MHz square wave clock provided by discrete oscillator and
32.678 kHz sleep clock produced by the EM ASIC D1420 with an external crystal.
Figure 58 Clocking scheme
Interfaces
Bluetooth
Bluetooth data interface is connected to UART1 of application processor D4800. UART is an asynchronous
interface for transferring data and control information to BT device.
RX-34
System Module
Issue 2
COMPANY CONFIDENTIAL
Page 9 –7
Copyright © 2007 Nokia. All rights reserved.
