TVP5160
SLES135E–FEBRUARY 2005–REVISED APRIL 2011
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2.3 Clock Circuits
An internal line-locked PLL generates the system and pixel clocks. A 14.31818-MHz clock is required to
drive the PLL. This may be input to the TVP5160 decoder at 1.8-V level on terminal 121 (XIN), or a crystal
of 14.31818-MHz fundamental resonant frequency may be connected across terminals 121 (XIN) and 122
(XOUT). If a parallel resonant circuit is used as shown in Figure 2-4, then the external capacitors must
have following relationship:
CL1 = CL2 = 2CL – CSTRAY
Where,
CSTRAY is the pin capacitance with respect to ground
CL is the crystal load capacitance specified by the crystal manufacturer
Figure 2-4 shows the reference clock configurations. The TVP5160 decoder generates the SCLK signal
used for clocking data.
NOTE
See crystal data sheet for correct loading specifications.
TVP5160
TVP5160
121
122
121
122
14.31818-MHz
1.8-V Clock
XIN
XIN
CL1
14.31818-MHz
Crystal
R
CL2
XOUT
NC
XOUT
Note: The resistor (R) in parallel with the crystal is recommended to support a wide range of crystal types. A 100-kΩ resistor
may be used for most crystal types.
Figure 2-4. Reference Clock Configuration
2.4 Real-Time Control (RTC)
Although the TVP5160 decoder is a line-locked system, the color burst information is used to accurately
determine the color subcarrier frequency and phase. This ensures proper operation with nonstandard
video signals that do not follow exactly the required frequency multiple between color subcarrier frequency
and video line frequency. The frequency control word of the internal color subcarrier PLL and the
subcarrier reset bit are transmitted via the terminal 83 (GLCO) for optional use in an end system (for
example, by a video encoder). The frequency control word is a 23-bit binary number. The instantaneous
frequency of the color subcarrier can be calculated from the following equation:
F
CTRL
FPLL
=
× FSCLK
233
where FPLL is the frequency of the subcarrier PLL, FCTRL is the 23-bit PLL frequency control word and
FSCLK is the 2× pixel frequency.
22
Functional Description
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