Tx Uhf Lo Schematic; Tx Uhf Lo (Tx Ic) Troubleshooting - Nokia 6275 Rf Description And Troubleshooting

6275/6275i (RM-154)
RF Description and Troubleshooting

Tx UHF LO Schematic

The following partial schematic is for general reference only. See the Schematics chapter
for complete detailed versions.
Lock voltage

Tx UHF LO (Tx IC) Troubleshooting

There are two fixed LOs, 3296.16~3395.88MHz for cell band and 3700~3819.90MHz for
PCS band. This is the first LO for up-conversion. Be sure to monitor the control voltage at
R7001. When the N7000 LO is locked, this control voltage should be between 1.2 and
1.8Vdc.
Measure the frequency by
probing the top of the chip
PCS:
3760 MHz (CH600) -54 dBm
Cell:
3346.08MHz (CH384) -57 dBm
Page 46
Loop filter components
Figure 43: Tx UHF LO schematic
Lock voltage:
DC between 1.0 and 1.8 V
Vcc_Vco: 2.3 V
VR6: 2.8 V
VR1B: 4.8 V
Figure 44: Tx UHF LO layout and test points
Company Confidential
VIO: 1.8 V
VR2: 2.8 V
Issue 1 - September 2006