Technical Summary - Nokia NHM-7 series Service Manual

PAMS Technical Documentation

Technical Summary

Baseband is running from power rails 2.8V analog voltage and 1.8V I/O
voltage. UPP core voltage Vcore can be lowered down to 1.0V, 1.3V and
1.5V. UEM includes 6 linear LDO (low drop–out) regulators for baseband
and 7 regulators for RF. It also includes 4 current sources for biasing pur-
poses and internal usage. UEM also includes SIM interface which has
supports both 1.8V and 3V SIM cards.
Note: 5V SIM cards are no longer supported by NHM–7 baseband.
A real time clock function is integrated into the UEM which utilizes the
same 32kHz clock supply as the sleep clock. A backup power supply is
provided for the RTC which keeps the real time clock running when the
main battery is removed. The backup power supply is a rechargeable sur-
face mounted capacitor. The backup time with the capacitor is 30 minutes
minimum.
The analog interface between the baseband and the RF section is han-
dled by a UEM ASIC. UEM provides A/D and D/A conversion of the in–
phase and quadrature receive and transmit signal paths and also A/D and
D/A conversions of received and transmitted audio signals to and from
the user interface. The UEM supplies the analog TXC and AFC signals to
RF section according to the UPP DSP digital control. Data transmission
between the UEM and the UPP is implemented using two serial busses,
DBUS for DSP and CBUS for MCU. RF ASIC, Hagar, is controlled
through UPP RFBUS serial interface. There is also separate signals for
PDM coded audio. Digital speech processing is handled by the DSP in-
side UPP ASIC. UEM is a dual voltage circuit, the digital parts are running
from the baseband supply 1.8V and the analog parts are running from the
analog supply 2.78V also VBAT is directly used by some blocks.
The baseband supports both internal and external microphone inputs and
speaker outputs. UEM also includes third microphone input which is used
in NHM–7 for FM radio. Input and output signal source selection and gain
control is done by the UEM according to control messages from the UPP.
Keypad tones, DTMF, and other audio tones are generated and encoded
by the UPP and transmitted to the UEM for decoding. A buzzer and exter-
nal vibra alert control signals are generated by the UEM with separate
PWM outputs.
NHM–7 has two external serial control interfaces: FBUS and MBUS.
These busses can be accessed only through production test pattern.
EMC shielding for baseband is implemented using a metallized plastic
frame and UI PWB ground plane. On the other side the engine is shielded
with PWB grounding. Heat generated by the circuitry will be conducted
out via the PWB ground planes.
NHM–7 radio module is implemented to 8 layer PWB. UI module is divid-
ed between main PWB LA5 and separate UI PWB LK5.
Issue 1 10/2001
E Nokia Corporation
NHM–7
System Module & UI
Page 9