Rainbow Electronics MAX7445 User Manual

General description, Applications, Features

General Description

The MAX7445 4-channel, buffered video reconstruction
filter is ideal for anti-aliasing and DAC-smoothing video
applications or wherever analog video is reconstructed
from a digital data stream (such as cable/satellite/ter-
restrial set-top boxes, DVD players, hard-disk recorders
(HDRs), and personal video recorders (PVRs)). This
device operates from a single +5V supply and has a
flat passband out to 5MHz with a stopband attenuation
of 43dB at 27MHz. This makes it ideal for use with
NTSC, PAL, and standard-definition digital TV (SDTV)
video systems. Each output is capable of driving two
standard 150

Ω video loads.

The MAX7445 has three modes of operation. Mode 1
processes CVBS and RGB video signals. Mode 2
processes CVBS, Y, and C signals, as well as a second
asynchronous CVBS video signal. Mode 3 processes
RGB and CVBS (asynchronous) video signals. An exter-
nal pin adjusts the gain of the video buffer to either +6dB,
+9.5dB, or +12dB to accommodate video-encoder DAC
output signals of <1V. High-frequency boost circuitry pro-
vides picture sharpness with +1.2dB of gain boost with-
out degradation in the stopband. The output video drivers
can be disabled with an external pin.

The MAX7445 is available in a 14-pin TSSOP package
with an exposed pad, and is specified over the -40°C to
+85°C extended temperature range.

Applications

Set-Top Boxes/HDRs

DVD Players

Game Consoles

Digital VCRs

Desktop Video Editors

Features

♦ 4-Channel Filter and Buffer for CVBS, RGB, or Y/C

Video Signals

♦ Filter Response Ideal for NTSC, PAL, and

Interlaced SDTV Video Signals

♦ 43dB (typ) Stopband Attenuation at 27MHz
♦ ±0.75dB (max) Passband Ripple Out to 5MHz
♦ Blanking Level Voltage on Cable <1V
♦ Each Channel Drives Two 150Ω Video Loads
♦ +5V Single-Supply Voltage
♦ Selectable Gain: +6dB, +9.5dB, and +12dB
♦ Small 14-Pin TSSOP Package

MAX7445

4-Channel Video Reconstruction Filter

________________________________________________________________ Maxim Integrated Products

GAIN

GND

MAX7445

OUTA

OUTB

OUTC

OUTD

Ω

*OPTIONAL CAPACITORS

INA

0.1

µF

0.1

µF

0.1

µF

0.1

µF

INB

INC

IND

D/A

ENCODER

D/A

SYNC

DETECTOR

LOWPASS

FILTER

LOWPASS

FILTER

LOWPASS

FILTER

LOWPASS

FILTER

SYNC

DETECTOR

DISABLE

SELECT

Functional Diagram

Ordering Information

19-2948; Rev 0; 8/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

*EP = Exposed pad.

Pin Configuration appears at end of data sheet.

PART

TEMP RANGE

PIN-PACKAGE

MAX7445EUD

-40°C to +85°C

14 TSSOP-EP*