FLY DS105 Service Manual

FLY DS105 Service Menu

Version number:V1.0

2010-07-01

SAGETEL MOBILES (NINGBO) CO.，LTD

1. The Working Principle of MTK Platform Mobile Phone

This MTK platform mobile consists of the baseband part (MT6223D) and RF part

(transceiver MT6139N and power amplifier SKY77542).

1.1 The Diagram of Mainboard Circuit

(Integrated), Memory, CPU, Keyboard, LCD module, Audio circuit, RF circuit

and etc. As shown in the following figure1:

Figure 1

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1.2 Distribution of the mainboard components

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1.3 The Process of Mobile Phone Power Supply and Power on

1.3.1 The Power Supply Module Part

① VDD，For CPU MN100 and peripheral circuit.
② VCORE 1.8\1.2V，For CPU MN100.
③ VM For memory: Flash.

1.3.2 Mobile Power On Process

The process of mobile phone power on\off is mainly driven by Power management、
CPU and memory. While the phone is added cell, VBAT voltage is immediately
produced, and the boot trigger-PWRKEY of the power module is high level. When

the power on or off button is pressed, the voltage of PWRKEY is lowered at once,
generating 26MHz clock. At the same time, VDD、VCORE etc. and Reset Signal (/
SYSRST) is transmitted by the Power Management Module to CPU. After receiving
the system clock、Reset Signal (/ SYSRST) and some logical signal, CPU will run
the power-on program from ROM/RAM. When the mobile is successfully running,

CPU will transmit the message of Boot to maintain the signal. The signal is
received by the Power Module, which maintains all levels of the voltage to achieve
the purpose of the work of the mobile.

1.4 Schematic Diagram of RF Part

The RF part of the MTK mobile phone consists of MT6139N, Power Amplifier and
Front-end Switch filter module. The RF circuit has two major functions: First,
it receives the selected RF signal from the antenna, demodulates the baseband
signal and then transmits this lower frequency signal to CPU. Second, it
modulates the baseband I, Q signals into the designated RF frequency and
amplifies the power to radiate the signals from the antenna. As shown below:

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