CVBS Video Filter Amplifier with SmartSleep

and Bidirectional Video Support

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13

Full-Operation Mode

If a load is connected to an output, the corresponding

filter and amplifier turn on and remain on until the out-

put load is disconnected. In full-operation mode,

SmartSleep intelligently reduces the supply current

based on the input signal presence and output loading.

Figures 4, 5, and 6 show which portions of the

MAX9513 turn on and which remain off with different

load configurations.

When an amplifier is on, it continually checks if the load

has been disconnected by detecting if the amplifier

output is sourcing current during a horizontal line time.

If no sourcing current is detected within one horizontal

line time (approximately 64µs), the load has been dis-

connected and the amplifier returns to active-detect

mode. If, at any time, the input video signal is removed,

the MAX9513 returns to standby mode.

If the SmartSleep feature is not activated and the part is

not in shutdown, the filters and amplifiers completely

turn on, regardless of whether there is a video signal at

the CVBSIN input and whether there are loads connect-

ed at the outputs.

EXTCVBSIN

CVBSOUT1

CVBSIN

CVBSOUT2

GND

+3.3V

CLAMP

OFF

75

Ω

BUFFER

LOAD SENSE

6dB

75

Ω

LOAD SENSE

6dB

LPF

MAX9513

2.9mA PLUS

LOAD CURRENT

CVBS1

75

Ω

SHDN

INT/EXT

ACTIVE VIDEO

DETECT

SMARTSLEEP

CONTROL

LOGIC

+3.3V

OFF

CVBS2

+3.3V

VIDEO SIGNAL

PRESENT

0

TO

50mV

CURRENT

DAC

Figure 4. Full-Operation Mode with CVBSOUT1 Loaded