M52347SP/FP

Rev.2.00 Sep 14, 2006 page 10 of 16

Application Method

1. Input Block

1) GREEN (SYNC ON VIDEO) IN (Pin 4)

Input with sync negative polarity.

Comparison of pin 4 input signal and the reference voltage of the inside of the IC performs the synchronous

separation. When the input at pin 4 is less than or equal to the reference voltage (2.8 V) and the flowing current is

more than or equal to the input sensitivity current (200

µA or more), the signal is separated.

When only a synchronous signal is input into pin 4, the operatable amplitude and the duty are as shown in Figure 1.

If the IC does not operate normally with the video signal input, change the value of external resistance R to make

the current optimum.

But, when capacity value is too big, output response becomes bad.

2) COMP/H IN, VIN (pins 6 and 8)

The composite sync input is connected to pin 6. H and V of the separate sync input are connected to pins 6 and 8,

respectively. For each of pins 6 and 8, the bias is 2.5 V and the impedance is 10 k. The internal double threshold

converter is used for shaping waveform and for detecting polarity.

Average DC voltage of input signal is 2.5 V. Each threshold voltage is set at a voltage 0.3 V away from this voltage.

of duty test.

Only 5 V TTL input, decrease the amplitude by resistor splitting.

In addition, Figure 4 shows an example for improving the capability of the allowable duty when the input amplitude

To use the IC out of the standard value, remove the filter from pins 7 and 9, observe the waveform and check for a

match with the waveform shown in Figure 5.

30

0

5

10

15

20

25

00.2

0.4

0.6

0.8

1.0

4

R = 56 k

Ω

R = 75 k

Ω

f = 100 kHz

3.3

µ

R

Figure 1

Small POSI Duty

Large NEG Duty

≈ 2.8 V

≈ 2.5 V

≈ 2.2 V

Figure 2