AN2760 Datasheet, PDF (7/14 Pages) STMicroelectronics – Using clock distribution circuits in smart phone system design

AN2760 Conventional cell phone clock solutions compared to the STCD10x0 integrated solution
1.4
Integrated STCD10x0 clock solution in MID application
Mobile Internet Device (MID) represents a new category of small and truly mobile devices
which integrate the advantages of both UMPC (Ultra-Mobile PC) and mobile phones. This
application has recently gained much attention and the trend to incorporate many types of
wireless connection technologies such as WLAN, BT and GPS into MIDs. The STCD10x0
solution provides significant benefit to the MID clock solution, not only in system cost but
also in PCB area. The connection of the STCD10x0 clock solution in MIDs is also illustrated
in Figure 3.
1.5
Integrated STCD10x0 clock solution in multimode RF front-
end
In multimode mobile RF front-end, multiple reference clocks are typically used for the
transceivers. Figure 4 gives an example of TD-SCDMA/GSM dual-mode mobile RF front-
end clock application. Alternatively, the clock from VCTCXO could be distributed by
STCD10x0 to the TD-SCDMA transmitter and receiver and GSM transceiver separately.
Figure 4. Typical application circuit using STCD1040 in dual-mode mobile RF front-
end
VCTCXO
VCC
VCC
MCLK
STCD1040
EN4
CLK4
EN3
CLK3
EN2
CLK2
GND
EN1
CLK1
Mode
selection
TD-SCDMA
transmitter
TD-SCDMA
receiver
GSM
transceiver
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