Applications Information

Power-Supply Considerations

The MAX7481/MAX7482 operate from a +2.7V to +3.6V

single supply and require proper layout and bypassing.

For best performance, place components as close as

possible to the device.

Proper grounding improves performance, minimizes

crosstalk, and prevents any switching noise from cou-

pling into the video signal. Connect GND (pin 2) and

CPGND together at a single point on the PCB. Route

CPGND and all traces carrying switching transients

away from GND traces and components in the video

1µF capacitor to GND, placed as close as possible to

with a 1µF capacitor to CPGND, placed as close as

bypass with a low-ESR 1µF capacitor to CPGND as

close as possible to the device.

Bidirectional Video Filters/Buffers for Composite

and S-Video Portable Media Devices

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11

LOWPASS FILTER

CLAMP

CLAMP

CHARGE PUMP

ADC

DAC

ADC

YCON

75

Ω

+6dB OR +7dB

C

CVBS

Y

BIAS

C1P

C1N

REGULATOR

CVBSON

GND

IN1

IN2

OUT4

IN3

IN5

IN4

100k

Ω

+6dB OR +7dB

+6dB OR +7dB

+6dB

+6dB

1

μF

OUT5

OUT2

OUT3

OUT1

150

Ω

150

Ω

P/R

C2 = 1

μF

75

Ω

75

Ω

C1 = 1

μF

1

μF

C4 = 0.1

μF

C5 = 0.1

μF

C3 = 0.1

μF

LOWPASS FILTER

0.1

μF

0.1

μF

MAX7481

MAX7482

DAC

Functional Diagram/Typical Application Circuit