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NJM2267

DUAL VIDEO 6dB AMPLIFIER WITH 75Ω DRIVER

Japan Radio Corporation  

NJM2267

SAG correction circuit generates a low frequency component signal amplified to Vout terminal.

Changes of the luminance signal will be low-frequency components, if you want to output a large signal luminance changes.

Therefore, generate correction signal of change of a luminance signal to Vout pin.

At this time, signal is over the dynamic range of Vout pin. This may cause a lack of sync signal, and waveform distortion.

Please see diagram below (green waveform), if you want to output large changes of a signal luminance, such as 100% white

video signal and black signal. Thus, output signal exceed dynamic range of Vout pin and may be the signal lack.

Input signal

Waveform of Vout

Dynamic range of Vout

Waveform of Vout1

The sync signal is missing because exceed the dynamic

range of Vout.

< Countermeasure for waveform distortion >

1. Please using small value the Sag compensation capacitor (CSAG).

It can ensure the dynamic range by using small value the capacitor (CSAG). It because of low-frequency variation of Vout pin

is smaller. However, the output (COUT) must be use large capacitor for this reason sag characteristics become exacerbated.

2. Please do not use the sag correction circuit.

Signal can output within dynamic range for reason it does not change the DC level of the output terminal.

However, the output (COUT) must be use large capacitor for this reason sag characteristics become exacerbated.

3. To increase the power supply voltage

Internal reference voltage is dividing the power supply voltage and GND.

Therefore, it can ensure the dynamic range by increasing the power supply voltage.

Ver.2016-06-06

-7-

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