LG VX5400, Service Manual

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Isolation2
34 dB min(PCS Tx
Æ
GPS)
1.2.2 LNAs (U107)
The RFL6000 has cellular and PCS LNAs, respectively. The characteristics of Low Noise Amplifier (LNA)
are low noise figure, high gain, high intercept point and high reverse isolation. The frequency selectivity
characteristic of mobile phone is mostly determined by LNA.
The specification of VX5400 LNAs are described below:
Low gain Middle gain High gain Units Parameter
Cellular PCS Cellular PCS Cellular PCS
Gain
-19 -20 -2 -9 15.5 16 dB
Noise Figure 19 20 2 9 1.4 1.6 dB
Input IP3 25 25 20 20 6 8 dBm
1.2.3 Down-converter Mixers and GPS LNA (U111)
The RFR6000 device performs signal down-conversion for Cellular, PCS and GPS tri-band applications. It
contains all the circuitry (with the exception of external filters) needed to support conversion of received RF
signals to baseband signals. The three downconverting Mixers (Cellular, PCS and GPS), and an LO Buffer
Amplifier to buffer the RF VCO to the RF Transmit Upconverter. The GPS LNA & mixers offer the most
advanced and integrated CDMA Rx solution designed to meet cascaded Noise Figure (NF) and Third-order
Intercept Point (IIP3) requirements of IS-98C and J-STD-018 specifications for Sensitivity, Two-Tone
Intermodulation, and Single-tone Desense.
Operation modes and band selection are specially controlled from the Mobile Station Modem MSM6050.
The specification of VX5400 Mixers are described below:
Low gain High gain Units Parameter
Cellular PCS Cellular PCS
Noise Figure 27 27 11 11 dB
Input IP3
4 3 4 3 dBm
Input IP2 50 50 75 70 dBm
1.2.4 Rx RF SAW FILTER(F100)
The main function of Rx RF SAW filter is to attenuate mobile phone spurious frequency, attenuate noise
amplified by the LNA and suppress second harmonic originating in the LNA.
LGE Internal Use Only Copyright@2007 LG Electronics. Inc. All right reserved.
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Only for training and serving purposes
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