Video Filter Amplifier with SmartSleep and

Bidirectional Video Support

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11

CVBS 1

CIN

YIN

EXTCVBSIN

COUT

YOUT

CVBSOUT1

CVBSIN

CVBSOUT2

LPF

GND

+3.3V

CLAMP

OFF

LOAD SENSE

6dB

75Ω

75Ω

LPF

BUFFER

LOAD SENSE

BUFFER

BUFFER

6dB

LOAD SENSE

6dB

75Ω

LOAD SENSE

6dB

75Ω

LPF

MAX9508

7µA

SVIDEO

CHROMA

SVIDEO

LUMA

CURRENT

DAC

CURRENT

DAC

NO VIDEO

SIGNAL

CURRENT

DAC

VIDEO ENCODER

SHDN

INT/EXT

ACTIVE VIDEO

DETECT

SMARTSLEEP

CONTROL

LOGIC

+3.3V

+3.3V

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

CVBS 2

Figure 2. Standby Mode

outputs. If the SmartSleep feature is not activated and

the part is not in shutdown, the filters and output ampli-

fiers completely turn on, regardless of whether there is

a video signal at the CVBSIN input and whether there

are loads connected at the outputs.

SmartSleep only works with DC-coupled loads.

Standby Mode

In standby mode, the filters and output amplifiers are

off and only the active video detect circuit is active.

Quiescent current consumption is approximately 7µA

(Figure 2). The active video-detect circuit checks if

sync is present on the CVBSIN signal. If no sync is

detected the device remains in standby mode.