S1M8660A Datasheet, PDF (18/32 Pages) Samsung semiconductor – RX IF / BBA WITH GPS

S1M8660A (Preliminary)
RX IF/BBA WITH GPS
CHIP×8 Clock Generator
CHIP×8 CLOCK is a digital division that divides the 19.68MHz TCXO by 512/1025. It holds the TCXO clock by
half cycle every 512th TCXO cycle and strictly speaking it does not generate 9.8304MHz precisely. The
9.8304MHz is the mean on the 1025TCXO cycle, where 9.84MHz of 50% duty is obtained from 1 to 512 and 513
to 1024. The timing diagram in Figure 9 explains this. The CHIP×8 CLOCK output is held at low when the CDMA
is asleep and FM is idle. Moreover, it can use three division ratios(19.68MHz, 9.84MHz, 9.8304MHz) through the
serial I/F. Various external chip clocks can be used by converting them to inputs. In operating in GPS mode,
input should be changed in order that the signal of GPS sampling frequency can be applied.
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TCXO
CHIPx8
1023 1025 1027
1024 1026
2/ftcxo
Figure 11. CHIP×8 Clock form
Rx Voltage Controlled Oscillator(VCO)
S1M8660A includes the Rx LO block having the VCO and quad-phase generator. The quad-phase generator
outputs I-phase and Q-phase clocks with 1/2 the VCO frequency and sends them to the QPSK modulator. The
VCO buffer is used when the VCO output is sent to the external RX PLL. Although the allowable VCO frequency
is determined based on an external time constant, it can only range between approx. 100MHz to 500MHz,
suggesting that the maximum input IF frequency is 250MHz.
Serial Port Interface(SPI)
S1M8660A is equipped with the Serial I/F. All internal functions can be controlled through a common bus using
an external controller. The serial I/F can be used by setting pin 26(SEN) high, the pin which permits/ not permit
the SPI. If the SEN becomes low, the SPI cannot be used and the S1M8660A must be used DC control mode.
(All the internal registers are default value) In GPS mode, for the compatibility with the former products, it is
designed to be uncontrollable with DC control. So, in case of GPS mode, the SEN pin should be set high and
then it can be controlled through serial interface. S1M8660A is designed to be completely compatible with MSM
series of Qualcomm, and compatible with S1M8656A except for GPS function. Here, the modem is the master
and S1M8660A the slave.
Each pin which uses the SPI bus has the following common functions.
• The STB(STROBE) for the serial bus start signal is used to initialize serial data transmission.
This pin is used with the IDLEB function in manual mode and designated the IDLEB/STB pin.
• Serial BUS DATA is used for the bi-direction data input /output at serial data transmission.
This pin is used with the FMB function in parallel mode and designated the FMB/DATA pin.
Because it is an open drain type pin, it requires the pull-up resistance of approx. 8kΩ.
• Serial BUS CLK is used to synchronize the data input/output at serial data transmission.
This pin is used with the SLEEPB function in manual mode and designated the SLEEPB/CLK pin.
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