Rf Engine; Main Processor; Energy Management - Nokia RM-272 Service Manual

RM-272; RM-273
System module
• SDRAM and NOR flash memories

RF engine

The RF module performs the high frequency operations of the engine for GSM. In both transmitter and
receiver, the modulator and demodulator operate at the channel frequency.
The core components of the RF module are:
• Ahne RF ASIC (application specific integrated circuit)
• Front end module (FEM) module (Power amplifier and Antenna switch)
The RF engine also includes:
• Voltage controlled oscillators (VCO and VCTCXO)
• SAW filters
The baseband section controls the RF module through the serial bus, RFBus. This passes information about
eg. frequency band and mode of operation. Ahne RF ASIC controls the mode of operation, and further sends
control signals to the front end module.
In addition to the RFBus there are other interface signals for the power control loop, VCTCXO control and for
the modulated waveforms.

Main processor

The main processor in this device is RAPGSM, a BB5.0 ASIC.
Some of its interfaces, processors and controllers are:
• General purpose UARTs
• Processor modules
• I2C (between ICs) interface
• GSM coder
• Interfaces to user interface, SIM and MMC
• Accessory interface
• Handling of RF-BB interface
• I/O voltage = 1.8 V, Core voltage <1.8 V

Energy management

Two ASICs manages the energy in the phone; Retu and Tahvo. Together they cover the analogue audio and
energy management function needs.
Tahvo
All blocks that need a special silicon process are included in Tahvo.
Tahvos main features are:
• Energy management control
• Supply voltage generation
• Charge control
• Digital core supply
• Current control for LED supply
Retu
The blocks that do not have special needs are included in Retu.
Retu controls for example:
Issue 1 COMPANY CONFIDENTIAL Page 5 –9
Copyright © 2007 Nokia. All rights reserved.