Receiver Logic Input Voltages; Rx Front-End Receiver Troubleshooting - Nokia 6275 Rf Description And Troubleshooting

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Receiver Logic Input Voltages

Measure logic levels for Rx Front-End (N7160).
voltages.
Table 5 includes the logic levels for the N7160.
If the logic levels are significantly off (± 0.2V), replace the Back-End IC (N7100). If the
levels are still bad, replace the Rx Front-End IC (N7160) and re-measure. If the voltages
are still out of specifications, refer to the Baseband Troubleshooting chapter.

Rx Front-End Receiver Troubleshooting

Keep the following points in mind regarding the Rx Front-end receiver:
• There is a separate LNA for 800MHz (Cell and AMPS) and 1900MHz (PCS).
• There is a separate RFA (inside Rx Front-end IC) for 800MHz (Cell and AMPS) and
1900MHz (PCS).
• After the RFA, there is a mixer, and then the signals are separated by CDMA (Cell
and PCS) and AMPS.
Issue 1 - September 2006
3
1
Figure 26: Receiver logic input voltage test points
Table 5: Rx Front-end (N7160) Logic Levels
Modes
1
IF_SEL
Cell CDMA High Gain 0 V
Cell CDMA Low Gain 0 V
PCS CDMA High Gain 0 V
PCS CDMA Low Gain 0 V
AMPS High Gain 2.7 V
AMPS Low Gain 2.7 V
Company Confidential
RF Description and Troubleshooting
Figure 26 shows the receiver logic input
2
Logic Input Voltages
2 3
BAND GAIN_CTL
0.1 V 2.7 V
0.1 V 0 V
2.7 V 2.7 V
2.75 V 0 V
0.1 V 2.7 V
0.1 V 0 V
6275/6275i (RM-154)
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