STV2246H STMicroelectronics, STV2246H Datasheet - Page 24

• Manufacturer Part Number: STV2246H
• Manufacturer: STMicroelectronics

Specifications of STV2246H

• Lead Free Status / Rohs Status: Compliant

green DC levels for black point adjustment takes
place via the bus.
3.4.9 Bus-controlled Contrast & Saturation
The Contrast Control regulates internal RGB, ex-
ternal RGB and OSD RGB inputs. The maximum
attenuation on internal and external RGB inputs is
-24 dB and is limited to -12 dB for OSD RGB in-
puts. The bus-controlled saturation range is 50 dB.
3.4.10 Bus-controlled Brightness & Sharpness
The total brightness range is 60% of the black-to-
white amplitude at maximum contrast. The bright-
ness control regulates all RGB sources (internal,
external and OSD). Bus-controlled Sharpness
(peaking) is provided in PAL/SECAM/NTSC
standards.
3.4.11 Bus-controlled Coring on Sharpness
When
switched ON, the peaking function is not active on
low amplitude signals (below 10 IRE).
3.4.12 Black Stretch
The Black Stretch circuit can be disabled via the
bus. Two modes are provided, one to be used
when the video signal is transmitted with a set-up
(7.5IRE set-up in NTSC), the other to be used
when the video signal is transmitted without a set-
up (PAL/SECAM).
3.4.13 Bus-controlled Blue Screen
The bus-controlled Blue Screen feature is used to
insert a blue background on the screen when no
video is available. The RGB OSD can be dis-
played when the blue screen is active.
3.4.14 White Insertion
This function is used to force a full white screen at
RGB output via the I²C bus or during Soft mode at
Powerdown.
3.4.15 Automatic RGB Peak Regulation (APR)
The APR function is used to take advantage of the
total RGB output range. APR circuits detect the
peak level of the RGB outputs (before OSD inser-
tion) and regulate the RGB gain (contrast) so that
signals above the APR threshold are limited. For
example, at maximum drive and contrast levels
with the APR function switched OFF, the 100 IRE
input signal gives 3 V(B/W) to the RGB outputs.
With APR ON and the APR threshold at 70 IRE,
the 70 IRE input signal gives 3 V (B/W) at RGB
outputs. For input signals above 70 IRE, the APR
will decrease the RGB gain so that amplitude at
the RGB output is always 3 V (B/W). The APR
gain control voltage is memorized on an external
capacitor where the gain decrease is very fast and
the gain increase is very slow (several frames).
the
Coring-on-sharpness
STV224X, STV228X, STV223X - FUNCTIONAL DESCRIPTION
function
is
The APR function can be enabled or disabled via
the I²C bus.
APR ON when register 10 hex d0 = 1 and register
07 hex d6 = 0.
3.4.16 RGB Peak Limitation
The APR function can be switched into an RGB
Peak Limitation function via the I²C bus: register
07 hex, data d6 = 1 and register 10 hex d0 = 1.
For this purpose, the APR threshold, tracked with
the contrast for the APR function, is changed in a
fixed threshold that is independent of the contrast.
In this case, the APR threshold I²C control should
be set to its maximum value.
3.5 CHROMA CIRCUIT
3.5.1 PAL/SECAM/NTSC Decoders
SVHS Chroma input; bus-controlled SVHS mode.
– 30 dB Automatic Color Control (ACC) range.
– Integrated chroma base band delay line and ON/
– Automatic standard identification, with possibility
– 3-crystal application capability for the South
3.5.2 PAL/NTSC Decoder
ACC carried out by peak detector on synchronous
demodulation of the burst.
Fully-integrated killer function.
VCO using two standard crystals: 4.43 MHz and
3.58 MHz. One crystal is internally selected de-
pending on the standard selection. A third crystal
can be used in PAL/NTSC applications only.
VCO reference signal is available on Pin X1.
– 4.433619 MHz Crystal specification.
– 3.579545 MHz Crystal specification (NTSC M).
The ACC function is an automatic gain control of
the color amplifier.
OFF bus control.
of forcing the standard via the bus.
American market:
The first crystal on Pin XTAL1 (3.5X MHz only),
the second crystal on Pin XTAL2 (3.5X MHz on-
ly), and the third crystal on Pin XTAL3/BTUN
(3.5X MHz only, used for PAL/NTSC application
only).
Mode of operation: serial resonance (without
load capacity),
Motional capacitance: C
Shunt capacitance: C
Serial resistance: R
Mode of operation: serial resonance (without
load capacity),
Motional capacitance: C
S
< 70Ω.
P
< 7pF,
M
M
= 13fF ±3fF,
= 11fF ±3fF,
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