Nokia 2220 Servicehandbuch
RH-42
System Module
CCS Technical Documentation
Page 12
Nokia Corporation Confidential
Issue 2 09/2003
UEM
Introduction to UEM
UEM is the Universal Energy Management IC for digital hand portable phones. In addi-
tion to energy management, it performs all the baseband’s mixed-signal functions.
tion to energy management, it performs all the baseband’s mixed-signal functions.
Most UEM pins have 2kV ESD protection, and those signals considered to be more easily
exposed to ESD, have 8kV protection within the UEM. These kinds of signals are (1) all
audio signals, (2) headset signals, (3) BSI, (4) Btemp, (5) Fbus, and (6) Mbus signals.
exposed to ESD, have 8kV protection within the UEM. These kinds of signals are (1) all
audio signals, (2) headset signals, (3) BSI, (4) Btemp, (5) Fbus, and (6) Mbus signals.
Regulators
The UEM has six regulators for baseband power supplies and seven regulators for RF
power supplies. The VR1 regulator has two outputs: (1) VR1a and (2) VR1b. In addition to
these, there are two current generators — IPA1 and IPA2 — for biasing purposes.
power supplies. The VR1 regulator has two outputs: (1) VR1a and (2) VR1b. In addition to
these, there are two current generators — IPA1 and IPA2 — for biasing purposes.
A bypass capacitor (1uF) is required for each regulator output to ensure stability.
Reference voltages for regulators require external 1uF capacitors. Vref25RF is the refer-
ence voltage for the VR2 regulator, Vref25BB is the reference voltage for the VANA,
VFLASH1, VFLASH2, VR1 regulators, Vref278 is the reference voltage for the VR3, VR4,
VR5, VR6, VR7 regulators, and VrefRF01 is the reference voltage for the VIO, VCORE reg-
ulators and for the radio frequency (RF).
ence voltage for the VR2 regulator, Vref25BB is the reference voltage for the VANA,
VFLASH1, VFLASH2, VR1 regulators, Vref278 is the reference voltage for the VR3, VR4,
VR5, VR6, VR7 regulators, and VrefRF01 is the reference voltage for the VIO, VCORE reg-
ulators and for the radio frequency (RF).
The
VANA regulator supplies the baseband’s (BB) internal and external analog circuitry.
It is disabled in the Sleep mode.
The
Vflash1 regulator supplies the LCD, the digital parts of the UEM and Taco ASIC. It is
enabled during startup and goes into the low Iq-mode when in the Sleep mode.
The
VIO regulator supplies both the external and internal logic circuitries. It is used by
the LCD, flash and UPP. The regulator goes into the low Iq-mode when in the Sleep mode.
BB
RF
Current
VANA: 2.78Vtyp 80mA max
VR1a:4.75V 10mA max
VR1b:4.75V
VR1b:4.75V
IPA1: 0-5mA
Vflash1: 2.78Vtyp 70mA max
IPA2: 0-5mA
Vflash2: 2.78Vtyp
40mA max
40mA max
VR2:2.78V 100mA max
VIO: 1.8Vtyp
150mA max
150mA max
VR4: 2.78V 50mA max
Vcore: 1.0-1.8V
200mA max
200mA max
VR5: 2.78V 50mA max
VR6: 2.78V 50mA max
VR7: 2.78V 45mA max