Supply Voltage Regulators - Nokia NSB-7 Series Service Manual

PAMS Technical Documentation
Based on 47 kohm ± 5 % NTC with B = 4090 ±1.5 %. Without any alignment, with that
and 1 % pull-up resistor, ± 2.5 _C accuracy is achieved between - 20 and +60 _C (± 3.5
_C @ -40 ... +85 _C).

Supply Voltage Regulators

The heart of the power distribution is the CCONT. It includes all the voltage regulators
and feeds the power to the whole system. The baseband digital parts are powered from
the VBB regulator which provides 2.8V baseband supply. The baseband regulator is active
always when the phone is powered on. The VBB baseband regulator feeds MAD and
memories, VCORE for MAD core, COBBA digital parts and the LCD driver in the UI section.
There is a separate regulator for a SIM card. The regulator is selectable between 3V and
5V and controlled by the SIMPwr line from MAD to CCONT. The COBBA analog parts are
powered from a dedicated 2.8V supply VCOBBA. The CCONT supplies also 5V for RF and
for flash VPP. The CCONT contains a real time clock function, which is powered from a
RTC backup when the main battery is disconnected. The RTC backup is rechargable poly-
acene battery. The battery is charged from the main battery voltage by the CHAPS when
the main battery voltage is over 3.2V.
Operating Mode Vref
Power off Off
Power on On
Reset On
Sleep On
Issue 1 06/00
VBATT
BATTERY
BSI
BTEMP
R
T
NTC
BGND
Figure 8: Standard Battery BTEMP connection
RF REG VCOBBA
Off Off
On/Off On
Off On
VR1 On
Off Off
ãNokia Mobile Phones Ltd.
TRANSCEIVER
VREF
100k
10k
BTEMP CCONT
VBB VSIM SIMIF
Off Off Pull-down
On On On/Off
On Off Pull-down
On On On/Off
NSB-7
System Module
Vcore
Off
On
On
On
Page 19