SDA9257 Infineon Technologies Corporation, SDA9257 Datasheet - Page 22

• Manufacturer Part Number: SDA9257
• Description: Clock SYNC Generator
• Manufacturer: Infineon Technologies Corporation

Semiconductor Group
to adapt the nominal frequency of the DTO by means of 5
such shifting the center frequency according to the momentary standard used.
For the different applications the following values of INC are allowed (values valid for
a crystal frequency of 24.576 MHz):
Application
PAL
NTSC
PAL (100 Hz/VGA) 31250
NTSC (120 Hz/VGA) 31500
ATV
MUSE
Macintosh
VGA
Note: A change of INC causes spontaneous changes of the generated clock
The DTO generates a saw-tooth with a frequency that is proportional to the increment.
The saw-tooth is converted into a sinusoidal clock signal by means of a D/A converter
and applied to an analog PLL which multiplies the frequency and minimizes residual
jitter.
By means of the
can be set. In this manner a clock is provided that is line-locked with the SYNC-input
signal. The ratio of these clock frequencies to the horizontal frequency of SYNC depends
only on the
For the different modes the following values of S1CL and S2CL are allowed:
Mode
CCIR
CCIR
4:2:2, 4:1:1 enabled
4:2:2, 4:1:1 enabled
VGA
VGA
The digital horizontal PLL supplies a noise-suppressed horizontal pulse.
frequencies!
I
2
YUV-ADC 2FH
enabled
enabled
disabled
disabled
C-Bus bits S1CL, S2CL, HPLL and 2FH.
I
2
C bits S1CL and S2CL the output frequency on pins CLK1 and CLK2
FH [Hz]
15625
15750
32400
33750
35000
38000
0
0
0
0
1
1
2FH
0
0
1
1
1
1
1
1
S1CL
11
11
11
10
01
10
22
S2CL
11
00
11
00
11
11
YUV-ADCs
active
inactive
inactive
active
inactive
inactive
inactive
inactive
I
2
C-Bus bits (INC4...INC0)
f
(MHz)
27
27
27
13.5
6.25 ... 8.75 25 ... 35
12.5 ... 17.5 25 ... 35
CLK1
INC
6
6
6
6
8
11
14
21
f
(MHz)
27
tristate
27
tristate
SDA 9206
CLK2
1999-02-10