LG C3100, Руководство по обслуживанию

Страница: 17 / 119

3.2 Power Amplifier Module (RF3133, U400)
The RF3133 is a high-power, high-efficiency power amplifier module with integrated power
control. The device is self-contained with 50
Ω
input and output terminals. The power control
function is also incorporated, eliminating the need for directional couplers, detector diodes,
power control ASICs and other power control circuitry; this allows the module to be driven
directly from the DAC output.
The device is designed for use as the final RF amplifier in GSM 850, E-GSM 900, DCS and PCS
handheld digital cellular equipment and other applications in the 824-849 MHz, 880-915 MHz,
1710-1785 MHz, and 1850-1910 MHz bands.
On-board power control provides over 37 dB of control range with an analog voltage input
(TX_RAMP); and, power down with a logic “low” for standby operation (TX_ENABLE).
External control (BAND_SELECT) is used to select the GSM or DCS band with a logic high or
low. A logic low enables the GSM band whereas a logic high enables the DCS band.
Figure 3-5. Functional Block Diagram of RF3133
- 16 -
1 DSC/PCS IN
2
3
4
5
6
7
BAND SELECT
TX ENABLE
VBATT
VREG
VRAMP
GSM IN
DSC/PCS OUT
VCC2
VCC2
VCC OUT
GSM OUT
11
8
12
10
9
3. TECHNICAL BRIEF