12dB Gain Setting

100k

ance at the node is 50k

Ω. No additional connection is

necessary since the pin offers a minimum noise margin

Output Clamp Level

When sync pulses in the luma signal (Y) are detected,

the DC restore loop is activated. The function of the

loop is to set the sync tip of the video signal to the

desired DC level of 0.8V for YOUT and COUT and the

average DC voltage of COUT at 1.6V.

Applications Information

Input Considerations

Use a 0.1µF ceramic capacitor to AC-couple the input

to the MAX7443/MAX7444. This input capacitor stores

a DC level such that the outputs are clamped to the

appropriate DC voltage level.

Output Considerations

The outputs of the MAX7443/MAX7444 are typically

connected to a 75

Ω series back-match resistor fol-

lowed by the video cable. Because of the inherent

divide by two of this configuration, the blanking level of

the video cable is always less than 1V, which complies

with industry-standard video requirements. The video

buffer can also drive an AC-coupled video load. Good

video performance is achieved with an output capacitor

as low as 220µF.

Power-Supply Bypassing and Layout

The MAX7443/MAX7444 operate from a single +5V

Place all external components as close to the device as

possible. Refer to the MAX7443 evaluation kit for a

proven PC board layout example.

Exposed Pads

Both the SO and thin QFN packages of the MAX7443/

MAX7444 have exposed pads on the bottom of the

packages. These pads are electrically connected to

GND and should be connected to the ground plane for

improved thermal conductivity. Do not route signals

under these packages.

Chip Information

TRANSISTOR COUNT: 4252

PROCESS: BiCMOS

Triple-Channel Video Reconstruction Filter and

Buffer for Composite and Y/C Outputs

_______________________________________________________________________________________________________

5

GSET

GAIN (dB)

GND

6

9.5

Open

12

Table 1. Gain-Setting Control

COUT

GND

1

2

8

7

YOUT

CVOUT

GSET

CIN

YIN

3

4

6

5

THIN QFN

TOP VIEW

COUT

GND

1

2

8

7

YOUT

CVOUT

GSET

CIN

YIN

3

4

6

5

SO

MAX7443

MAX7444

MAX7443

MAX7444

Pin Configurations

Selector Guide

PART

HIGH-FREQUENCY BOOST

MAX7443ETA

No

MAX7443ESA

No

MAX7444ETA

Yes

MAX7444ESA

Yes