cxa1645p Sony Electronics, cxa1645p Datasheet - Page 12

• Manufacturer Part Number: cxa1645p
• Description: Rgb Encoder
• Manufacturer: Sony Electronics

Notes on Operation
Be careful of the following when using the CXA1645P/M.
1. This IC is designed for image processing of personal computers and video games. When using the IC in
2. Be sure that analog RGB signals are input at 1.0Vp-p maximum and have low enough impedance. High
3. The SC input (Pin 6) can be either a sine wave or a pulse in the range from 0.4 to 5.0Vp-p.
4. When designing a printed circuit board pattern, pay careful attention to the routing of the V
5. SC and SYNC input pulses
6. Connecting an external resistor to the 75 driver output pin
other video devices, make thorough investigations on image quality.
impedance may affect color saturation, hue, etc. Inputting RGB signals in excess of 1.3Vp-p may disable
the clamp operation.
However, when a pulse is input, its phase may be shifted several degrees from that of the sine wave input.
In the IC, the SC input is biased to 1/2 V
deviates from 50%, High- and Low-level pulse voltages may exceed V
subcarrier distortion. In such a case, be very careful that the duty factor keeps to 50%.
leads. To decouple the V
characteristics. Ground the capacitors by connections shown below as closely to each IC pin as possible.
Try to design the leads as short and wide as possible.
Design the pattern so that V
Attach a resistor and a capacitor to eliminate high-frequency components of SC (Figure A) and SYNC
(Figure B) before input.
Be careful not to input pulses containing high-frequency components. Otherwise, high-frequency
components may flow into V
A capacitance of several dozen picofarads at each pin may start oscillation. To prevent oscillation, design
the pattern so that a 75 resistor is mounted near the pin (see Figure C).
When any of the 75
no parasitic capacitance is generated on the printed circuit board.
V
V
CC
CC
1, V
2
REF
Fig. A
... GND1
... GND2
driver output pins is not in use, leave it unconnected and design the pattern so that
CC
2.2k
CC
CC
and V
, GND and peripheral parts, resulting in malfunctions.
(or V
REF
REF
Fig. C
pins, use tantalum, ceramic or other capacitors with good frequency
) is connected to GND via a capacitor at the shortest distance.
5P
CC
. Accordingly, when a 5.0Vp-p pulse is input and the duty factor
75
Make these leads short.
– 12 –
Fig. B
2.2k
CC
and GND in the IC, which causes
47P
CC
CXA1645P/M
and GND