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The IFC (Ul 01) is mainly consist of IF interface part and AUDIO CODEC part. The IF interface part, witch
is between RF part (mainly U301) and BEC, translate RF data to baseband data for BEC. Mainly, IF
interface part is consist of receiver, transmitter, and some kind of RF control. The IFC also provides several
A/D inputs to monitor system parameters. Battery voltage is periodically measured after scaling via a
resistor divider (BAT MON: U101_67). A thermistor located near the PA is monitored to obtain temperature
status by TMP MON (U101 66).
Receiver interface
The U101 receive differential 1/Q signals (RX_IN, RX_I, RX_QN, RX Q: U101 48,49,5O,51), or DEMOD
signal (U101_52) which come from RF demodulator (U301_11,12,9,10,16), and translate as digital data.
These data is synchronized by control signals (RX_SYNC, RX CLK, and BBCLK: U101 31,32,40) is
transported to BEC through RX DATA (pin U101_30). in addition, the U101 uses AGC_OUT (U101 72) for
dynamic range of receiver signal strength connected to U301_17, AFC_OUT (U101_71) for adjusting
reference frequency exactly connected to TXCO (OSC302 1).
Transmitter interface
The U101 receives TX DATAI (U101 36) synchronized by control signals (TX SYNC, TX_CLK: U101_33,34),
which come from BEC, and translate this data as differential l/Q signals (TX_IN, TX 1, TX_QN, TX Q:
U101_61,60,58,57), or MOD signal (U101_63). it transports these data to RF modulation part. In addition,
the U101 uses PA CNT (U101_73),TX PWR (U101 68) for controlling power of transmitter.
AUDIO CODEC
Three audio paths are implemented in IFC. The primary path utilizes the microphone (U101_11,12) and
speaker (U 101_77,79). Both microphone and speaker utilize the main differentiai circuits in the IFC to
minimize noise pickup. The speaker output is amplified internally to enable direct connection to the
speaker. The second audio path connects to the headset jack. The headset microphone and speaker are
passed to the IFC's auxiliary input (U101_5) and output (U101_2), respectively. The headset jack terminals
indicate via the HS_SENSE (U106-2_7) to GPIO of BEC (U203_C11) when the headset is present. As well as
when the headset button is pushed via the SEND END (U106-1_1) to GPIO of BEC (U203 A13). The third
audio path to the HFK shares the auxiliary output with the headset for its speaker and uses the second
auxiliary input for its microphone. Since the auxiliary output is not internally amplified, an external audio
amplifier (U102) is applied before connection to the headset and HFK.
SAMSUNG Proprietary-Contents may change without notice
STH-N375
Circuit Description & Circuit Diagrams
6-5
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