Nokia RM-154, 6275, 6275i RF Description and Troubleshooting
Nokia Customer Care
6275/6275i (RM-154)
Mobile Terminals
RF Description and
Troubleshooting
Issue 1 - September 2006 Company Confidential ©2006 Nokia Corporation
6275/6275i (RM-154)
RF Description and Troubleshooting
Contents Page
Introduction ..................................................................................................................................................... 5
Preliminary RF Troubleshooting ..............................................................................................................6
RF Troubleshooting Equipment List ........................................................................................................7
Transmitter RF Troubleshooting ................................................................................................................. 8
Transmitter Schematics ............................................................................................................................. 9
Transmitter Troubleshooting Guidelines .............................................................................................11
Transmitter Troubleshooting Setup ......................................................................................................11
AMPS Tx Setup ....................................................................................................................................... 12
Cell Tx Setup ........................................................................................................................................... 13
PCS Setup................................................................................................................................................. 15
Transmitter RF Troubleshooting Procedures ......................................................................................16
Failed Test: Tx PA Detector ................................................................................................................. 17
Tx Output Spectrum.............................................................................................................................. 18
Tx RF Component Diagram ................................................................................................................. 19
Tx DC Probe Points ................................................................................................................................ 19
Tx RF Probe Points................................................................................................................................. 20
DC Test Points......................................................................................................................................... 20
Receiver RF Troubleshooting .................................................................................................................... 20
Receiver Block Diagram ...........................................................................................................................21
Receiver Schematics .................................................................................................................................22
RF AGC Status ............................................................................................................................................24
Turning on the Rx Path ............................................................................................................................25
Switching the Rx Gain States ................................................................................................................27
Receiver Diagnostic Signal Tracing ......................................................................................................27
Receiver RF Probe Points..................................................................................................................... 28
Receiver IF Probe Points ...................................................................................................................... 29
Receiver DC Probe Points .................................................................................................................... 30
Receiver Logic Input Voltages ................................................................................................................31
Rx Front-End Receiver Troubleshooting .............................................................................................31
Synthesizer Troubleshooting .................................................................................................................... 33
Synthesizer Block Diagram .....................................................................................................................34
Synthesizer Schematics ...........................................................................................................................35
Synthesizer Troubleshooting Setup ......................................................................................................36
Incorrect PLL Frequencies.................................................................................................................... 37
VCTCXO Troubleshooting .........................................................................................................................37
AFC Voltage Troubleshooting .................................................................................................................38
VCTCXO Manual Tuning....................................................................................................................... 39
UHF Synthesizer Schematic ....................................................................................................................41
UHF Synthesizer Troubleshooting .........................................................................................................41
PCS UHF LO CH600 Typical Spectrum .................................................................................................43
Rho and UHF LO..................................................................................................................................... 43
CELL UHF LO CH384 Typical Spectrum ...............................................................................................44
Rho and UHF LO..................................................................................................................................... 44
Rx VHF LO (Rx Back-End IC) Troubleshooting ...................................................................................45
Tx UHF LO Schematic ...............................................................................................................................46
Tx UHF LO (Tx IC) Troubleshooting .......................................................................................................46
UHF PCS Tx LO (3700 ~ 3819.90)/2MHz Typical Spectrum ..........................................................47
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Nokia Customer Care RF Description and Troubleshooting
UHF CELL Tx LO (3296.16 ~ 3395.88)/4MHz Typical Spectrum ...................................................48
GPS Troubleshooting................................................................................................................................... 49
GPS RF Block Diagram .............................................................................................................................49
GPS RF Schematic .....................................................................................................................................49
GPS Troubleshooting Setup ....................................................................................................................50
HW Self Test Failure.............................................................................................................................. 51
Oscillator Test Failure........................................................................................................................... 51
CW (Mode 3) Test Failure.................................................................................................................... 51
GPS DC Test Points................................................................................................................................ 52
GPS RF Troubleshooting Setup........................................................................................................... 53
GPS RF Probe Points.............................................................................................................................. 54
FM Radio Troubleshooting ........................................................................................................................ 55
FM Radio Schematic .................................................................................................................................55
FM Radio Testing .......................................................................................................................................55
FM Radio Parts Layouts ...........................................................................................................................56
FM Radio Probe Points .............................................................................................................................56
Bluetooth Troubleshooting ....................................................................................................................... 57
Bluetooth Schematic ................................................................................................................................57
Test Setup 1 ................................................................................................................................................58
Test Setup 2 ................................................................................................................................................59
Test Setup 3 ................................................................................................................................................60
Test Setup 4 ................................................................................................................................................61
Test Setup 5 ................................................................................................................................................62
Bluetooth Troubleshooting Flowchart .................................................................................................63
Bluetooth DC and RF Probe Points .......................................................................................................64
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RF Description and Troubleshooting Nokia Customer Care
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Nokia Customer Care RF Description and Troubleshooting
Introduction
The 6275/6275i mobile terminal is based on tri-mode, code division multiple access or
“CDMA,” dual-band engine. The variants include tri-mode terminals with and without
the GPS component.
Note: The 6275 variant is identical to the 6275i variant, except that the GPS is not
supported in the 6275 variant.
D2800
UEMEK
Figure 1: PWB components - top
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RF Description and Troubleshooting
Coupler
Diplexer
Duplexer
PA DC/DC converter
PCS PA
GPS
Cell PA
TX ASIC
VCO synthesizer
Bluetooth
RX circuits
Figure 2: PWB components - bottom
Preliminary RF Troubleshooting
Verify the following if the mobile terminal cannot make a call:
• The mobile terminal is in Normal or Test Mode (i.e., the mobile terminal is
searching for a signal, net server is on).
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Nokia Customer Care RF Description and Troubleshooting
• The Preferred Roaming List (PRL) is loaded into the mobile terminal (for Normal
mode).
• The mobile terminal is tuned and has passed tuning. Read the tuning parameters
using the Read Parameters component in Phoenix. An untuned mobile terminal
has all zeros in the tuning file.
• The call box channel is set for a channel in PRL.
• The SID is correct and entered into the mobile terminal. For Test mode, SID is 4
and paging channel is: 385/Cell and 1175/PCS.
• The VCTCXO is centered properly within tuning limits as described in the
"VCTCXO Manual Tuning" section on page 39.
• The transmitter and receiver are working properly in Local mode. See "Transmitter
RF Troubleshooting"onpage8 and "Receiver RF Troubleshooting"onpage20 for
detailed information.
RF Troubleshooting Equipment List
You will need the following equipment for RF troubleshooting:
• Computer with AMS version of Phoenix
• Agilent 8960 CDMA call box (or equivalent)
• Signal generator
• Power supply
• Digital multimeter
• Diagnostic test jig
• Spectrum analyzer
• AMS RF Probe, AAS-10A or AAS-10B
• Oscilloscope
• RF connectors and cables
• High impedance probe (optional)
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RF Description and Troubleshooting
Transmitter RF Troubleshooting
Following is the block diagram for the Tx RF system.
Figure 3: Transmitter system block diagram
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Nokia Customer Care RF Description and Troubleshooting
Transmitter Schematics
The following schematics are for general reference only. See the Schematics chapter for detailed versions.
FALSE_DET
VR2
C7022
GND
C7024
GND
C7027
3p3
L7001
27nH
C7023
1p2
L7002
33nH
L7003
1p2
0p5
27nH
GND
VR2
C7025
L7004
6n8H
C7026
0p5
L7005
12nH
L7006
6n8H
GND
R7010
0R
R7011
150R
R7012
C7029
C7031
C7030
3p3
GND
30p
3p3
GND
GND
180R
Z7000
B39841-B9003-E910
836.5MHz
OUT
IN
GND
GND
GND
Cell TX filter
Z7001
B39192-B9014-E910
1850-1910MHz
IN
OUT
GND
GND
GND
PCS TX filter
PA_INPUT_CEL
PA_INPUT_PC
PWROUT
TEMP
DCOUT
IREF_CEL
IREF_PCS
RF_BUS_ENABLE
RF_BUS_DATA
RF_BUS_CLK
TX_GATE
F_REF_TX
Loop filter
R7001
10k
C7005
R7002
100p
27k
C7006
2n2
GND
TX LO lock voltage
TX_IP
TX_IN
TX_QP
TX_QN
TX_AGC1
R7003
SHORT_CIRCUIT
R7004
SHORT_CIRCUIT
R7005
SHORT_CIRCUIT
R7006
SHORT_CIRCUIT
VR6
VR6
C7000
R7000
0R
10n
GND
C7003
3p3
C7015
GND
VR2
33p
GND
VIO
C7010
VR6
3p3
GND
C7007
100p
GND
GND
C7009
C7008
1u0
4p7
GND
GND
C7011
10n
C7013
C7012
18p
GND
GND
VIO
VR2
C7014
18p
33p
GND
GND
L7000
27nH
TX IC
C7004
220p
GND
JUPITER_D4_PMB3365G
31
ENABLE
32
DATA
33
CLOCK
34
TX_GATE
35
VDD_BUS
36
FREF
37
VDD_PLL
38
VDD_CP
39
CP
1
GND_CP
2
VTUNE
3
VCC_VCO30PDET_IN
4
VCC_LO5VCC_PA(4.75V)
9
BBI
10
BBIX
11
BBQ
12
BBQX
14
VCC_MOD
15
AGC_REF
16
AGC1
17
AGC2
18
VCC_RF
BOTTOM PLATE=
C7001
N7000
VR2
10n
GND
VCC_CDRV
ISET_DRV
VCC_PDRV
PDET_OUT
PDET_REF
COUTX
POUTX
ISET_PA
C7002
100n
GND
VR2
C7016
10n
VR2
C7018
C7017
20
22
COUT
23
19
27
24
25
POUT
R7009
21
NC
PWROUT_1
28
TEMP
29
DCOUT
6
7
IPA1
8
IPA2
GND
C7019
12p
10p
47p
GND
GND
12k
GND
VR1B
C7021
C7020
10n
18p
GND
GND
GND
PA_BIAS
R7007
22k
R7008
43k
GND
Figure 4: Transmitter schematic 1
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BLACKCOMB
RF Description and Troubleshooting Nokia Customer Care
GND
PCS PA
N7300
PA_INPUT_PCS LNA_PCS
IREF_PCS
R7300
0R
C7304
C7303
C7305
C7301
C7300
1n0
GND
C7302
3p3
10n
GND
GND
3p3
GND
C7306
1n015p
GND
GND
RF3448E5
5
RFin
RFout
RFout
1
Vid
NA(CX2)
23
NA(CX2)
Iref/Vref
6
NA
GND/NC
GND/NC
7
Vcc1
89
Vcc1
GND
24
Vcc1
GND
13
GND
Vcc2
Vcc220GND
GND
BOT_SURF=
10p
GND
PCS
C7326
3p3
15
16
C7307
3
4
2
18
14
17
22
GND
L7301
3n9H
NA
GND
GND
Couplers
VBAT
C7318
10U
GND
C7321
C7320
C7319
6n8
270p 1n0
GND
C7322
1n0
1n0
GND
GND
GND
C7323
Cell PA
N7301
RF3449E4
3
RFout
RFin
RFout
6
Vid
24
Iref
GND/NC
GND/NC
1
Vbias
7
Vcc18GND
12
Vcc2
18
Vcc2
C7324
3p3
GND
GND
BOT_SURF=
CELL
GND
C7325
7p5
15
16
20
NC
21
NC
4
13
2
GND
14
GND
17
GND
23
GND
L7306
22nH
GND
GND
PA_INPUT_CEL
IREF_CEL
R7306
VCC_PA
C7317
10U
GND
0R
PCS duplexer
Z7300
DUPLEX
TX
FILTER
R7302
SHORT_CIRCUIT
Z7302
TX RX
GND
Cell duplexer
PCS
RX
ANT
GND
GND
L7302
EHF4CM1880
6
DOUT 4
ROUT
1
IN 3
OUT
GND
GND
GND
GND
STPAC01F2
C3
RFIn
C2
C7314
GND
Gnd1
C1
Bias
B3
Gnd1
10p
GND
GND
R7307
ROUT
6
56R
OUT
1
GND
2
VR2
C7313
L7304
10nH
10n
GND
L7305
EHF4CM0836A
DOUT
4
IN
3
GND
5
GND
ANT
DUPLEX
FILTER
GND
GND
GND
GND
GND
GND
GND
GND
R7301
N7302
GND
Z7301
2
4
6
GND
56R
3
DIPLEXER
P1
P2
1
A2
VTemp
A3
DCout
B1
Gnd2
B2
Gnd1
GND
GND
X7300
In R2
5
In C1
P3
GND
SHORT_CIRCUIT
C7315
C7316
3n3
3n3
GND
GND
Power detector
R7304
GND
L7303
33nH
C7311
10p
GND
R7305
SHORT_CIRCUIT
R7308
47k
C7312
C7370
47p
NA
GND
47p
GND
R7310
0R
LNA_CEL
PA_TEMP
L7397
10nH
ANT_SENSE
TEMP
DCOUT
TP7300
TP7301
GND
GND
C7358
VBAT
C7356
C7357
10n
10U
GND
GND
VCC_PA
C7353
47p
10U
GND
GND
PA_DC_DC_PDM
PA_DC_DC_ENABLE
C7350
C7354
4u7
N7350
RF4013E2.2
GND
U//U
16
2
VRCVSET
5
VSENS
15
VBAT
14
3
VBAT
EN
4
13
CF
C7352
R7351
10p
GND
GND
R7352
8k2
NA
1k8
GND
C7351
47p
47p
GND
GND
6
GND
7
GND
1
NC10VOUT
8
NC VOUT
17=GND
VBAT
12
VOUT
11
VOUT
9
R7350
L7350
42R/100MHz
100R
C7355
L7351
4u7
1u5H
GND
Figure 5: Transmitter schematic 2
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Nokia Customer Care RF Description and Troubleshooting
Transmitter Troubleshooting Guidelines
Use the following guidelines when troubleshooting.
• Always perform visual inspection of PCB under microscope to check proper
placement, rotation, and soldering of components.
• Look for the presence of a well-defined CDMA modulated signal on a spectrum
analyzer at the correct frequency. If a signal is present but off frequency or the
shape looks distorted, check the synthesizer. Possibly, one of the synthesizers is
not locked or the VCO has no output signal. Check the synthesizers for proper
frequency and amplitude. See "Tx Output Spectrum" on page 18 and "Synthesizer
Troubleshooting"onpage33.
• Check that power supplies to the transmitter have the correct voltage. See "Tx RF
Component Diagram" on page 19.
• If the signal is very low in amplitude, check the probing diagram to determine
what part of the TX chain is ‘broken’. See "DC Test Points" on page 20.
• Check that AGC PDMs produce and adjust TX power within the proper limits.
Transmitter Troubleshooting Setup
Use the following sets of procedures to troubleshoot the transmitter using Phoenix.
1. Tx power at the RF connector.
2. All Tx DC points.
3. All soldering jig points for the whole Tx chain.
4. UHF LO presence:
• If the UHF LO is present, check the N7000 output.
• If the UHF LO is not present, it is a synthesizer problem.
5. If there is no N7000 output:
a. Change the N7000.
b. If the problem persists, reflow the duplexers, diplexer, and couplers.
c. If the problem persists, change the PA.
6. If there are several failed mobile terminals with the same symptoms, it may be
necessary to break one to determine the cause.
Use the following sections to set up troubleshooting in Phoenix according to the band
you are using:
•"AMPS Tx Setup"onpage12
•"Cell Tx Setup"onpage13
•"PCS Setup"onpage15
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RF Description and Troubleshooting
AMPS Tx Setup
Use the following procedures to prepare for AMPS Tx troubleshooting using Phoenix.
Note the 6236i variant does not support AMPS.
1. Connect the RF test connector to a spectrum analyzer.
2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a
USB port.)
3. Connect a power supply to the mobile terminal.
4. Open the Troubleshooting menu, and click Phone Control. The Phone Control
dialog box appears.
5. Click the LOCAL button in the Phone State tab to put the mobile terminal into
Local Mode.
Figure 6: Phone Control dialog box
6. Open the Troubleshooting menu, point to AMPS, and click AMPS Control. The
AMPS Control dialog box appears.
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Nokia Customer Care RF Description and Troubleshooting
Figure 7: AMPS Control dialog box
7. In the Function field, select Tx Control.
8. In the Set Channel field, type 384.
9. In the Power Level field, type 5.
10. Select the Transmitter ON and Use DSP 2 codes options.
11. Click Execute.
12. Configure the spectrum analyzer using the following values:
• Center Frequency = 836.52 MHz
• Span = 100 MHz
• Amplitude = 20 dBm
• Attenuation = Auto
• BW = Auto
Cell Tx Setup
Use the following procedures to prepare for Cell Tx troubleshooting using Phoenix.
1. Connect an RF test connector to a call box.
2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a
3. Connect a power supply to the mobile terminal.
4. On the Phone Control dialog box, click the LOCAL button in the Phone State
Table 1: RF PDM Values at Power Level 5
Description/Field Reference Value
AGC1 -512
PA_Bias 129
PA_DC_DC 197
USB port.)
area to put the mobile terminal into Local Mode. (See Figure 6 on page 12.)
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RF Description and Troubleshooting
5. Open the Troubleshooting menu, point to RF, and click RF Main Mode. The RF
Main Mode dialog box appears.
Figure 8: RF Main Mode dialog box for Cell Mode
6. Select the following values on the RF Main Mode dialog box:
• Band = Cell (CDMA)
• Channel = 384
• Mode = Rx/Tx
7. Click Set.
Note: Be sure that the “RF Main Mode set successfully” message appears in
the status bar.
8. Open the Troubleshooting menu, point to RF, and click CDMA Control. The
CDMA Control dialog box appears.
Do NOT select this option
Figure 9: CDMA Control dialog box for Cell Tx troubleshooting
9. Select the following values:
• State = Rho ON
• Band = Cell
• Radio Configuration = Mode 1: IS-95 Voice
Note: Do NOT select the Set default PDM values option.
10. Click Execute.
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11. Configure the spectrum analyzer using the following values:
• Center Frequency = 836.52 MHz
• Span = 100 MHz
• Amplitude = 20 dBm
• Attenuation = Auto
• BW = Auto
Table 2: RF PDM Values
Description/Field Reference Value
AGC1 -130
PA_Bias 85
PA_DC_DC 110
Pout 16dBm
PCS Setup
Use the following procedures to prepare for PCS Tx troubleshooting using Phoenix.
Current 340mA
1. Connect an RF test connector to a call box.
2. Connect the mobile terminal to the PC via a test jig. (The bottom connector is a
USB port.)
3. Connect a power supply to the mobile terminal.
4. Open the Troubleshooting menu, and point to Phone Control. The Phone
Control dialog box appears. (See Figure 6 on page 12.)
5. Click the LOCAL button in the Phone State area to put the mobile terminal into
Local Mode.
6. Open the Troubleshooting menu, point to RF, and click RF Main Mode. The RF
Main Mode dialog box appears. (See Figure 8 on page 14.)
7. Select the following values on the RF Main Mode dialog box:
• Band = PCS (CDMA)
• Channel = 600
• Mode = Rx/Tx
8. Click Set.
Note: Be sure that the “RF Main Mode set successfully” message appears in
the status bar.
9. Open the Troubleshooting menu, point to RF, and click CDMA Control. The
CDMA Control dialog box appears. (See Figure 9 on page 14.)
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RF Description and Troubleshooting
10. Select the following values on the CDMA Control dialog box.
• State = Rho ON
• Band = PCS
• Radio Configuration = Mode 1: IS-95 Voice
Note: Do NOT select the “Set default PDM values” option.
11. Click Execute.
12. Open the Troubleshooting menu, point to RF, and click PDM Control.
13. Configure the spectrum analyzer using the following values:
• Center Frequency = 1880 MHz
• Span = 100 MHz
• Amplitude = 20 dBm
• Attenuation = Auto
• BW = Auto
Table 3: RF PDM Values
Description/Field Reference Value
AGC1 -130
PA_Bias 85
PA_DC_DC 110
Pout at RF connector +15dBm
Current 340mA
Transmitter RF Troubleshooting Procedures
After Phoenix is set up using either the AMPS, Cell, or PCS setup procedures, use the
following steps to troubleshoot the transmitter.
1. Using a voltmeter, check to see that all VR2, VR6, and VR1B are on the transmit
system. (See "Tx RF Component Diagram"on page19.)
• If any are missing, look for SMD problems around the Tx IC and the UEMEK.
• If SMD is good, replace the UEMEK.
2. After all DC voltages are present, check the AGC control voltages. (See "AMPS Tx
Setup"onpage12, "Cell Tx Setup"onpage13, or "PCS Setup"onpage15.)
• If the voltages are incorrect, check the SMD around TX_AGC1.
• If the SMDs are correct, replace the D2800.
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3. Using an oscilloscope, check the I and Q input modulation wave forms at test
points. See "Tx RF Components of the PWB"onpage19. They should all be
present with an AC swing of about 500mVpp, with an offset of +1.2V.
• If one or more waveforms is missing, look for SMD problems around these
resistors.
• If the SMD is good, replace the UEMEK.
4. Use an AAS-10 RF probe to probe the Cell Tx output of the Tx IC.
• If there is no RF or low RF, look for a faulty SMD around the Tx IC.
• If the SMD is okay, replace the N7000.
5. Probe the PA input.
• If the level is low, look for an SMD issue on the Tx filter.
• Reflow or replace the filter as necessary.
6. Probe the PA output.
• If the RF is missing or low, look for Vbatt voltages and SMD issues on and
around the PA.
• If these are okay, replace the PA.
7. Probe the duplexer output.
• If the RF is missing or low, reflow or replace the duplexer.
8. Probe the coupler output.
• If the RF is missing or low, reflow or replace the coupler.
9. Probe the diplexer output.
• If the RF is missing or low, reflow or replace the diplexer.
Failed Test: Tx PA Detector
Use the following steps if you encounter a failed test for the Tx PA detector:
10. Use Phoenix to set the mobile terminal into Local Mode and activate the Tx with
default output power.
11. The output power at the RF test connector should be 15dBm ± 4dB. If not, adjust
the PDM values or troubleshoot per procedure above.
12. Using a voltmeter on DC, probe the detector output at C7315. The voltmeter
should read approximately 1.7V. If not, replace N7302.
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RF Description and Troubleshooting
Tx Output Spectrum
Following is the correct output of the mobile terminal on a spectrum analyzer with
100MHz span. Note that if you are using the AAS-10 probe with the mobile terminal
connected to the call box, the amplitude should be approximately -7dBm at the antenna
test point on the top of the PWB.
Figure 10: Correct output spectrum
Following is an example of incorrect output.
Figure 11: Incorrect output spectrum
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Tx RF Component Diagram
Following are the Tx RF components.
Tx IC
Tx DC Probe Points
Following are the Tx DC probe points of the PWB.
Tx UHF LO
Lock Voltage
1.2V
PCS Tx
SAW filter
Cell Tx
SAW Filter
VR6: VCC_PA:
2.8V 0-4.6V
PCS PA
Cell PA
Figure 12: Tx RF Components of the PWB
Iref_Cell:
~2.4-3.4V
Duplexer
Cell
Duplexer Detector
PCS
Diplexer
Cell
Coupler
PCS
Coupler
Power
I
Q
VR2:
2.76V
Tx IQ inputs
approx. 1.2 V
approx. 500 mV p-p (with O’scope)
AGC 1
Pin 16
0.1 to1.8V
Iref_Pcs:
2.3-2.9 V
Figure 13: Tx DC probe points
PA_DC_DC_PDM:
0-1.9 V
Power Detector Output (DCOUT)
PCS:
2.0V @ <5dBm
1.7V @ <15dBm
1.2V @ <23dBm
Cell:
2.0 V @ <5dBm
1.8 V @ <15dBm
1.4 V @ <23dBm
Issue 1 - September 2006 Company Confidential Page 19
6275/6275i (RM-154)
RF Description and Troubleshooting
Tx RF Probe Points
Figure 14 shows the Tx RF probe points of the PWB.
PCS Frequency 1880 MHz
PCS TX IC out:
-7 dBm -13 dBm +17 dBm
PCS PA in:
PCS PA out:
PCS Duplexer
out: +15 dBm
Diplexer out:
PCS +16 dBm
Cell +10 dBm
Amps +1 dBm
PCS PDM:
PA_DC_DC = 110
PA_Bias = 85
AGC1 = -130
Amps PDM:
PA_DC_DC = 197
PA_Bias = 129
AGC1 = -512
Pwr Detector in
PCS: -13 dBm
Cell: +4 dBm
Amps: -20 dBm
Cell TX IC out: -7 dBm
Amps -33 dBm
Cell, Amps Frequency 836.25 MHz
Cell PA in: -7 dBm
Amps -33 dBm
DC Test Points
Figure 15 shows the DC test points.
Vbatt 3.2 to 4.7 V
VR1B: 4.75 V (TX)
VR1A: 4.75 V (Synth)
VR2: 2.78 V (TX)
VR4: 2.78 V (RX)
VR7: 2.78 V (RX)
Cell PA out: +20 dBm
Amps -6 dBm
Figure 14: Tx RF probe points
VR6: Rx 2.78 V (TX)
Cell Duplexer out:
+20 dBm
Amps -7 dBm
VR5: Rx 2.78 V (RX)
Cell PDM:
PA_DC_DC = 110
PA_Bias = 85
AGC1 = -130
VIO 1.8 V
VR3: 2.78 V (Synth)
Figure 15: DC Test Points
Receiver RF Troubleshooting
The heart of the receiver is the Rx Front-end IC, which contains two LNAs and mixers.
The other components are passive. There are two RF SAW filters for the Cell and PCS
bands. In addition, there are two IF filters, an IF SAW for CDMA and an IF Crystal for
AMPS.
Page 20 Company Confidential Issue 1 - September 2006
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