H/W Sub System - LG -P970 Service Manual

3.12 H/W Sub System

3.12.1 RF Interface
The base band is connected via a DigRF high speed data interface with a maximum clock frequency of 312 MHz.
The pure digital interface enables the digital baseband to shrink efficiently, as all the analog functionality is
within the RFIC. All data and control traffic is multiplexed via the RX and TX interface lines. The IC features a high
level programming model enabling the complete compressed mode operation of the device in an RF engine
environment. It handles RX and TX power control, also incorporating the calibration data.
The complete timing is optimized for compressed mode operation of the transceiver, it controls the front end
components of the engine (PA´s, switches, LNA´s). Additionally a SPI control bus for front end component
control is available in the IC, which also enables the readback of data from external components, thus the
handling of functions like PA saturation, mismatch detection, overheating (incorporated in the closed loop
power control) can be adopted.
3.12.1.1 DigiRF Interface
- RESET_N : RESET Input Signal for master reset
- ALERT_N : 3G PLL Lock Status Output Signal
- SYS_CLK : 3G DigRF System Clock Output
- DI3_TX_DAT, DI3_TX_DATX : 3G DigRF TX Input Data (Positive / Negative)
- DI3_RX_DAT, DI3_RX_DATX : 3G DigRF RX Input Data (Positive / Negative)
3.12.1.2 About Clock
- REF_CLK_EN, SYS_CLK_EN, FSYS2_EN, FSYS3_EN
- AFC_DAC : AFC DAC Output; analog output: 12 bits
- XO_SUP : Supply Voltage Output for TCVCXO
- SYS_CLK : 3G DigRF System Clock Output
- FSYS2, FSYS3, FSYS4 : 26 MHz Reference Clock Output
3.12.1.3 General Control Logic Signals
- PA Control Outputs
PA_EN1, PA_EN2, PA_EN3, PA_EN4 : PA Control Output
PA_BSEL : PA Band Select Control Output
PA_MODE : PA Mode Select Control Output
PA_RAMP : PA Ramping Voltage for GMSK and 8-PSK; analog output: 11 bits
PA_BIAS: PA Bias Voltage PA_POW_DET
- Frontend Control
FE_CTRL1~6 : Front-end Control Output
SPI(SPI_CLK, SPI_SS, SPI_DRW) : FEM Control Interface
- LNA Control
LNA_CTRL1, LNA_CTRL2, LNA_CTRL3, LNA_CTRL4 : LNA Control Output
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3. TECHNICAL BRIEF
Only for training and service purposes