Nokia ra8 RF Description and Troubleshooting

Nokia Customer Care

7 - RF Description and

Troubleshooting

Issue 1 11/05 COMPANY CONFIDENTIAL

RA-8 7 - RF Description and Troubleshooting Nokia Customer Care

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Issue 1 11/05 COMPANY CONFIDENTIAL 2

RA-8 7 - RF Description and Troubleshooting Nokia Customer Care

Table of Contents

Page No

CMT RF................................................................................................................. 5

Top-level description.......................................................................................... 5

RA-8 test point locations................................................................................... 6

Test points ......................................................................................................... 7

RF implementation in RA-8.............................................................................. 11

Frequency plan ..............................................................................................11

RF block diagram ...........................................................................................12

Antenna switch module (ASM) .......................................................................13

DC characteristics ..........................................................................................13

RF characteristics ............................................................................................ 16

Channel numbers and frequencies ................................................................ 16

RF Troubleshooting..........................................................................................17

Receiver description and troubleshooting........................................................ 17

Rx front end ...................................................................................................17

Antenna .........................................................................................................17

Receiver characteristics .................................................................................18

General instructions for Rx troubleshooting ...................................................19

Transmitter description and troubleshooting.................................................... 26

Power amplifier ..............................................................................................26

RF ASIC Honi ................................................................................................26

AFC function ..................................................................................................27

Transmitter characteristics .............................................................................27

General instructions for Tx troubleshooting ................................................... 27

Additional information for EDGE troubleshooting ............................................ 34

Pictures of EDGE transmitter signals .............................................................38

Synthesizer description and troubleshooting................................................... 42

Frequency synthesizers .................................................................................42

General instructions for synthesizer troubleshooting .....................................42

Frequency Lists ..............................................................................................47

RF tunings after repairs ................................................................................... 50

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RA-8 7 - RF Description and Troubleshooting Nokia Customer Care

CMT RF

■ Top-level description

The RF module performs the necessary high frequency operations of theEGSM900/1800/1900 tripleband (EDGE) engine. Both the transmitter and receiver have been implemented by using direct conversion architecture which means that the modulator and demodulator operate at the channel frequency.

The core of the RF is an application-specific integrated circuit, Honi. Another co re component is a power amplifier module which includes two amplifier chains, one fo r EGSM900 and the other for GSM1800/GSM1900.

Other key components include

• 26 MHz VCTCXO for frequency reference

• 3296-3980 MHz SHF VCO (super high frequency voltage controlled oscillator)

• Antenna switch module (ASM)

• Three SAW filters

• BAW-LNA module

The control information for the RF is coming from the baseband section of the engine through a serial bus, referred later on as RFBus.

The whole RF circuitry is located on one side of the 8-layer PWB. EMC leakage is prevented by using a metal shield with gasket. The RF circuits are separated

into two blocks.

• PA, ASM, TK balun

• Honi RF IC, VCO + balun, VCTCXO, BAW-LNA, Rx filter, Tx filter

The RF transmission lines constitute of striplines and microstriplines after PA.

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■ RA-8 test point locations

Figure 1: Top view

J7510

J7510 TXQM

TXQM

J7511

J7511 TXIM

TXIM

J7503

J7503 RFBusClk

RFBusClk

J7512

J7512 TXIP

TXIP

J7501

J7501 RXQ

RXQ

J7504

J7504 RFBusEna1

RFBusEna1

J7502

J7502 RFBusData

RFBusData

J7508

J7508 TXC

TXC

L7603

Z7601

L7602

L7601

Z7602

R7503

L7604

R7602

Z7603

R7500

G7500

C7506

C7505

J7500

J7500 RXI

RXI

G7501

J7509

J7509 TXQP

TXQP

L7500

C7516

R7601

C7706

C7705

C7721

Z7600

C7702

R7705

R7707

R7710

R7712

J7506

J7506 TXA

TXA

J7505

J7505 Reset

Reset

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Figure 2: Bottom view

J7507 TXP

RF test connection

■ Test points

Table 1: Rx test points

Signal name: Ref:

LNAB_P Z7603 LNA_P Z7603 RXI J7500 RXQ J7501

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Table 2: Antenna switch test points

Signal name: Ref:

VANT_1 Z7600 VANT_2 Z7600 VANT_3 Z7600 GSM_Rx Z7600 DCS_Rx Z7600 PCS_Rx Z7600 TX_IN_EGSM Z7600

Table 3: Honi serial interface test points

Signal name: Ref:

RFBusClk J7503 RFBusEna1 J7504 RFBusData J7502 Reset J7505

Table 4: Synthesizer test points

Signal name: Ref:

VCO_out G7500 VCTCXO_out G7501

Table 5: GSM900 Rx Honi input test points

RX filter Z7601

Ref:

Inductor L7603 Inductor L7604

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Table 6: GSM1800 Rx Honi input test points

Ref:

Filter Z7602 Inductor L7601 Inductor L7602

Table 7: GSM1900 Rx Honi input test points

Ref:

BAW-LNA Z7603 pin 7 Resistor R7601 Resistor R7602

Table 8: Tx PA input test points

Signal name: Ref:

Rfin_900 R7705 Rfin_1800/190 R7710

Table 9: Tx filter/balun input test points

Signal name: Ref:

RfinP_900 C7721 RfinM_900 C7721 RfinP_1800_1900 C7705 RfinM_1800_1900 C7706

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Table 10: PA control signal test points

Signal name: Ref:

VPCTRL_900 R7707 VPCTRL_1800_1900 R7712 TXIM J7511 TXIP J7512 TXQM J7510 TXQP J7509 TXC J7508 TXP J7507 (test pad) TXA J7506

Table 11: Rx test points

Signal name: Ref:

VR1 VR2 C7516 VR3 L7500 VR4 VR5 C7505 VR6 C7506 VR7 R7500 VrefRF01 R7503 VBAT C7702

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RA-8 7 - RF Description and Troubleshooting Nokia Customer Care

■ RF implementation in RA-8

Frequency plan

The RF frequency plan is shown below. The VCO operates at the channel fre quency multiplied by two or four depending on the frequency band of operation. This means that the baseband modulated signals are directly converted up to the transmission frequency and the received RF signals directly down to the baseband frequency.

Figure 3: RF frequency plan

HONI

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RF block diagram

IN

Antenna

IN

OUT2

OUT1

Front end

INOUT

AGC

PCS1900

1

3

BAW-LNA

2

5

4

INOUT

SAW

DCS1800

INOUT

RF

IF

RF

LO

IF

INOUT

AGC

RF

LO

IF

module

OUT1

RF

IF

IN

SAW

IN

IN OUT

OUT2

OUT1

INOUT

IN OUT

INOUT

BIAS

IN OUT

Mode (GSM/EDGE)

IN OUT

OUT2

OUT1

IN

OUT2

EGSM 900

INOUT

AGC

RF

LO

IF

f/2

OUT

f

IN

RF

LO

IF

OUT

f

IN

AGC

IN OUT

AGC

IN OUT

AGC

IN OUT

AGC

IN OUT

1

2

5

3

4

f/4

AGC

IN OUT

AGC

IN OUT

IPA2

IPA1

INOUT

BIAS

Pwr det

Power amplifier

INOUT

HONI

INOUT

HONI

INOUT

AGC

INOUT

AGC

IN

MODPLL

VCO

SYNT_MIX

RX-MIX

1

2

5

3

INOUT

IN OUT

IN

4

3420 - 3980 MHz

INOUT

EGSM900

DtoS

INOUT

AGC

INOUT

AGC

PLL

OUT

REF LE1 CLK DATA

12 dB

AGC

f

IN

IN OUT

f

OUT1

42 dB / 6dB step

VCTCXO

26 Mhz

IN

OUT2

f/2

OUT

IN

OUT1

OUT2

IN

OUTAFC

INOUT

f/4

OUT

IN OUT

RF

LO

IF

f

IN

15 dB

OUT

RF

LO

IF

CNTR

IN OUT

TXP

OUT

DCS1800/PCS1900

IN

TXC

f/2

RF

LO

IF

IN

TXC

AGC

15 dB

IN OUT

RF

LO

IF

RXI

RXQ

AFC

Sys.clock

Data

Clock

Reset

Enable

TXIP

TXIM

TXQP

TXA

TXQM

TXP

TXC

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Antenna switch module (ASM)

Figure 4: ASM

DC characteristics

Regulators

The transceiver baseband section has a multi function analog ASIC, UEM, which contains among other functions six pieces of 2.78 V linear regulators and a 4.8 V switch ing regulator. All the regulators can be controlled individually by the 2.78 V logic directly or through a control register. Normally, direct control is needed because of switching speed requirement: the regulators are used to enable the RF-functions which means that the controls must be fast enough.

The use of the regulators can be seen in the power distribution diagram which is p resented in Figure 6, “Power distribution diagram,” on page 15.

The seven regulators are named VR1 to VR7. VrefRF01 is used as a reference voltage for Honi.

The regulators (except for VR7) are connected to the Honi. Different modes of operation can be selected inside the Honi according to the control information coming through the RFBus.

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DC supply currents

Figure 5: DC power supplies

Typical current consumption

The table shows the typical current consumption in different operation modes.

Operation mode

Power OFF < 10 uA Leakage current (triple band PA) Rx, EGSM900 75 mA, peak Rx, GSM1800/GSM1900 70 mA, peak Tx, power level 5, EGSM900 1700 mA, peak Tx, power level 0, GSM1800/

GSM1900

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1000 mA, peak

Current

consumption

Notes

RA-8 7 - RF Description and Troubleshooting Nokia Customer Care

Power distribution diagram

Figure 6: Power distribution diagram

Honi

LNA GSM1900

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