CXA2075M Ver la hoja de datos (PDF) - Sony Semiconductor

Número de pieza

componentes Descripción

Fabricante

CXA2075M

RGB Encoder

Sony Semiconductor 

CXA2075M

Notes on Operation

Be careful of the following when using the CXA2075M.

1. Be sure that analog RGB signals are input at 1.0Vp-p maximum and have low enough impedance. High

impedance may affect color saturation, hue, etc. Inputting RGB signals in excess of 1.3Vp-p may disable

the clamp operation.

2. The SC input (Pin 6) can be either a sine wave or a pulse in the range from 0.4 to 5.0Vp-p.

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 VCC. Accordingly, when a 5.0Vp-p pulse is input and the duty factor

deviates from 50%, High- and Low-level pulse voltages may exceed VCC and GND in the IC, which causes

subcarrier distortion. In such a case, be very careful that the duty factor keeps to 50%.

3. When designing a printed circuit board pattern, pay careful attention to the routing of the VCC and GND

leads. To decouple the VCC pin, use tantalum, ceramic or other capacitors with good frequency

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.

VCC1... GND1

VCC2... GND2

Design the pattern so that VCC is connected to GND via a capacitor at the shortest distance.

4. SC and SYNC input pulses

Attach a resistor and a capacitor to eliminate high-frequency components of SC (Fig. A) and SYNC (Fig. B)

before input.

2.2k

5P

2.2k

47P

Fig. A

Fig. B

Be careful not to input pulses containing high-frequency components. Otherwise, high-frequency

components may flow into VCC, GND and peripheral parts, resulting in malfunctions.

5. Connecting an external resistor to the 75Ω driver output pin

A capacitance of several dozen picofarads at each pin may start oscillation. To prevent oscillation, design

the pattern so that a 75Ω resistor is mounted near the pin (see Fig. C).

∗

∗

75

∗ Make these leads short.

Fig. C

When any of the 75Ω driver output pins is not in use, leave it unconnected and design the pattern so that

no parasitic capacitance is generated on the printed circuit board.

– 13 –

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