FLY IQ442 QUAD User manual

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.+TIANYU CONFIDENTIAL
Maintenance Work
Guide for IQ442 QUAD

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INTRODUCTION
This document is the maintenance work guide for IQ442 QUAD. The compile objective
describes the detail theory of IQ442 QUAD and offers a maintenance guide for the later
mass production and after service.
The readers of the document should be the debug worker of SMT and after-service. It will
be the work guide for them. At the same time, the other members of the IQ442 QUAD
project group can also refer to the documents.

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INTRODUCTION ................................................................................................................................. 2
1、System summary ......................................................................................................................... 4
1.1 The diagram of IQ442 QUAD： ........................................................................................... 4
1.2 The main components list: .................................................................................................. 5
2 The details of system model ........................................................................................................... 6
2.1 Radio model ........................................................................................................................ 6
2.1.1 The radio Transceiver ............................................................................................... 6
2.1.2 GSM signal’s path ..................................................................................................... 6
2.1.3 WCDMA signal’s path ............................................................................................... 8
2.2 Power management unit ................................................................................................... 10
2.2.1 The timing of system’s boot ................................................................................... 10
2.2.2 PMU output voltage ............................................................................................... 11
2.3 Memory ............................................................................................................................. 12
2.4 The reference for no- power ON mobile ........................................................................... 12
2.5 Audio model ...................................................................................................................... 13
2.5.1 MIC ......................................................................................................................... 13
2.5.2 Receiver .................................................................................................................. 13
2.5.3 Speaker ................................................................................................................... 14
2.5.4 Audio Jack ............................................................................................................... 14
2.6 Other peripherals .............................................................................................................. 15
2.6.1 Vibrator .................................................................................................................. 15
2.6.2 Touch panel circuit ................................................................................................. 15
2.6.3 Camera ................................................................................................................... 16
2.6.4 Light sensor circuit ................................................................................................. 17
2.6.5 G-sensor ................................................................................................................. 18
2.6.6 Bluetooth & WIFI module....................................................................................... 18
2.6.7 GPS ......................................................................................................................... 20
2.6.8 LCD ......................................................................................................................... 21
2.7 Peripheral interface IO ...................................................................................................... 22
2.7.1 USB interface .......................................................................................................... 22
2.7.2 Side key................................................................................................................... 22
2.7.3 TF Card and USIM Card interface ................................................................................... 23
3. The factory happened case ......................................................................................................... 23
Epilog ....................................................................................................................................... 24

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1、System summary
1.1 The diagram of IQ442 QUAD：
The below is the diagram of IQ442 QUAD, which consist of main function blocks for the
phone. It can help find the root cause for different issues.
Diagram 1.1 The function block
The mobile consists of below main parts:
1. The baseband model:
It contains of the main baseband core parts, it includes the CPU,Memory, PMU etc.
2. The radio model:
It contains of the mobile radio parts; it includes RF6285 IC and other radio parts, for
example RF PA, SAW filter, duplexer, ant switch, and LNA, etc.
3. The audio parts:
It contains the mobile of audio, MIC, speaker, receiver, and headset.

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4. The peripheral parts:
It concludes the peripheral parts of mobile, USB,BT, WIFI,GPS, T-flash, Dual SIM-card,
g-sensor, LCM, Touch panel, front and back camera, light sensor, etc.
1.2 The main components list:
IQ442 QUAD hardware board consists of main board、sub-board、front-camera FPCA and on-key
FPC.
1. the main board parts list:
 U101: It is the system CPU, and it controls baseband、radio、audio、peripheral parts,
such as the TP, side-key, LCM, back light led, g-sensor, light-sensor, motor, cameras,
t-flash card, etc.
 U202: MCP memory of EMMC+SDRAM. EMMC is the AP+BP code; SDRAM is the RAM.
 U802：Power management unit. It is for system power supplies, the system charge,
the system power ON, the SIM care level translation, and monitoring the system
analog ADC.
 U804：DC-DC, it is for CPU core power supply.
 U203 、U204：Load switch, it is for the memory power supply.
 X1101：System clock. It supports the 19.2M system clk.
 U1101： Transceiver which is for radio TX and RX signal.
 U1207：Antenna switch. It is used for different working mode, it also contains the full
mode GMS power amplifier, GSM TX signal is from U1101 to U1207 and it is internal
PA amplifier, to antenna radio.
 U1206：PCS1800 和DCS1900 RX saw filter.
 U1207：GSM850 和EGSM900 RX saw filter.
 U1205：WCDMA BAND 1 TX saw filter.
 U1203：WCDMA BAND 1 TX power amplifier.
 U1210：WCDMA BAND 1 duplexer.
 U1202：WCDMA BAND 8 TX saw filter.
 U1209：WCDMA BAND 8 TX PA。
 U1201: WCDMA BAND 8 duplexer.
 U1602： BT&WIFI 的FEM
 U1604：WIFI IC
 U1607：Bluetooth IC
 J1702：LCM connector
 J1704：Touch panel connector
 U703： the LCM backlight led driver IC
 U1708：g-sensor
 J1501： the connector for main board and sub-board
 J1505：T-flash socket
 U5403、U5404：SIM socket
 J1402： the connector for front camera, light –sensor and Power-ON key
 J1403：The main camera
 J1401：JTAG connector

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 U1401：The flash LED
 U1801，U1803：GPS saw filter
 U1802：GPS LNA
 U501： audio amplifier
 J5460：the volume down/up key
 J5351：headset socket
2 The details of system model
U101 is the AP+BP CPU, U202 is the AP&BP memory, the system can power up while they
are working normally. The bad soldering can cause the system abnormal working.
2.1 Radio model
2.1.1 The radio Transceiver
U1101 is the transceiver which supports GSM and WCDMA mode.
Diagram 2 RF transceiver
2.1.2 GSM signal’s path
1. Tx path
As below diagram 3，the high band (1900/1800)and low band(850/900) come from U1101

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Diagram 3 GSM’s high and low bands signals come out from the U1101
When GSM’s high and low bands come out from U1101, after a resistor attenuator network,
input the U1204 from PIN9 and PIN10，then come out again from U1207’s PIN25 after they be
amplified in it.
Diagram 4 GSM high and low bands signals power amplify
GSM high and low bands signals after through the J1203, then through the RF cable and arrive
J1203 which is on antenna sub board, then after through the antenna match network，were
radiated by the antenna.
Diagram 5 Antenna radio
2. RX path
GSM’s signal was received by antenna，and reach the J1203 on main board after through the
path on Figure 5 and the RF cable .Then the signal enter the U1204 from PIN25（path on the
figure 4 ‘s left part）。 GSM high and low bands signals were divided in U1204 and came out
from U1207’ PIN19 and PIN21 respectively , and then they arrived the saw filter .The high band
signal entered in U1206，The low band signal entered in U1207。When they came out from the
saw filter ,they have become the differential signals .These differential signals enter in the

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U1101 after they through the match network. The path described above can refer to figure 6
and figure 7.
Diagram 6 GSM radio RX
Diagram 7 GSM RX signals into TSC (U1101)
2.1.3 WCDMA signal’s path
IQ442 QUAD supports wcdma band1 and band8.They will be described as below:

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Such above diagram showing, the WCDMA L/H band signals are output from U1101;
TX_WCDMA_LB is low band signal, TX_WCDMA_HB_SE is high band signal.
1. WCDMA BAND 1 TX path:
Band1’s tx signal comes from U1101, and after through some match networks and tx saw filter
U1205, it arrives band1’s PA U1203, then enter in diplexer U1210, then enter the switchU1204.
The below diagram shows the signal path from left to right: the filter, PA, diplexer, and into
U1204 from U1204 PIN17.
Diagram 8 WCDMA BAND1 TX
Band1’s signal comes out from U1204’PIN26.The signal ‘s path after U1204 is same as gsm signal
path .The detail can refer to figure 4 and figure 5 .
Note：From diagram 8, there is a power detector circuit shared by band1 and band8 which is
used to detect the tx power by U1101. The tx signal is power amplifier by PA, the CPL_IN is the
detector net (R1216, R1217, R1218). VMOUDE_0 and VMODE_1 is the modifying the PA gain.
2. WCDMA BAND 8 TX path:
Band 8 tx path is same as band1. The tx signal comes from U1101 ,and then through saw filter
U1202, PA U1209, diplexer U1201,and then enter the U1204.The details was described as below:
from the left to right, the saw filter, pa, diplexer, and ant switch
Diagram 9 WCDMA BAND8 TX
The signal ‘s path after U1204 is same as gsm signal path .The detail can get from figure 4 and
figure 5 .
3. Band1 and band 8 rx path
WCDMA’s rx signal was received by antenna, then through the path described in figure 4 and
figure 5, then arrival the diplexer.
When the BC1 and BC8’s rx signal arrival their diplexer respectively, BC1’s signal comes out

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from U1210’s PIN1, then enter in U1101 after through C1252. BC8’s signal comes out from
U1201’s PIN1and PIN8 which is a differential signal. Then it enters in U1101 after through a
match network and C1201 and C1209.The path was described in figure 10 as below.
Diagram 10 WCDMA BC1 and BC8 RX
After BC1’s signal entered in U1101, in order to improve the SN parameter, The transceiver
amplified the signal first in its internal LNA, and then puts out the BC1‘s signal. The signal was
filtered through U1102, and last they enter the U1101 again. The path described above can
refer to the diagram 11.
Diagram 11 WCDMA BC1 rx LNA
2.2 Power management unit
U802 is the system’s power manager unit，abbreviation PMU. It‘s responsible for system’s
battery’s charge and discharge, boot and shutdown, providing all the power needed by system.
2.2.1 The timing of system’s boot
1. When the power key was pressed down ,or the test point TP1412 was short to ground，
U802’s pin of K11 which was called by name PHONE_ON_N was became low level.
2. PMU initialize, and turn the pinN11 to low，and turn on the switch of system’s power