Rainbow Electronics MAX7439 User Manual
General description, Applications features, Ordering information
General Description
The MAX7438/MAX7439 three-channel standard defini-
tion video reconstruction filters include a back-porch
clamp that sets the output blanking level of the video
signal to ground. Each channel of the MAX7438/
MAX7439 combines a lowpass filter with adjustable
high-frequency boost levels and an output buffer capa-
ble of driving two standard 150
Ω video loads. The
blanking level of the output video signal on each chan-
nel is clamped to ground, eliminating the need for large
AC-coupling output capacitors. Direct input coupling
circuitry eliminates the need for AC-coupling input
capacitors. This DC-in/DC-out architecture results in
extremely low line-time distortion. The MAX7438/
MAX7439 are ideal for antialiasing and DAC smoothing
in digital video devices such as STBs, DVDs, PVRs,
and hard disk recorders. The MAX7438/MAX7439 oper-
ate from ±5V dual supplies.
The three-channel MAX7438/MAX7439 are ideal for Y,
P
b
, P
r
, and RGB component video signals, three com-
posite video signals, and also Y/C plus CVBS video sig-
nals. Each filter channel achieves 60dB of attenuation at
27MHz and a maximally flat passband from DC to 5MHz.
The MAX7438 offers an internal gain of +2V/V, while the
MAX7439 offers a gain of +3V/V.
Applications
Features
♦ Back-Porch of Video Output Signal Clamped to
Ground
♦ Eliminates Input/Output AC-Coupling Capacitors
♦ 0.1% Line-Time Distortion
♦ Stopband: 55dB at 27MHz
♦ Passband: ±0.8dB out to 5MHz
♦ Diff Gain = 0.05%, Diff Phase = 0.05 Degrees
♦ Output Clamped to Ground with Loss of Input
♦ Each Output Drives Two 150Ω Video Loads
♦ Up to 2dB of High-Frequency Boost Control
♦ Ideal for CVBS, Y/C (S-Video), and RGB (Y, P
b,
P
r
)
Outputs for NTSC, PAL, and SDTV
♦ Filter Bypass Mode
♦ Small 20-Pin 5mm
✕
5mm Thin QFN Package
MAX7438/MAX7439
Triple-Channel Video Reconstruction Filters with
Back-Porch Clamp to GND
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
19-2857; Rev 0; 4/03
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.
PART
TEMP RANGE
PIN-PACKAGE
MAX7438ETP
-40°C to +85°C
20 Thin QFN-EP*
MAX7439ETP
-40°C to +85°C
20 Thin QFN-EP*
*EP = Exposed paddle
Pin Configuration appears at end of data sheet.
EVALUATION KIT
AVAILABLE
IN1
IN2
IN3
MAX7438
MAX7439
ENCODER
V
SS
= -5V
V
CC
= +5V
EXT
10k
Ω
GND
BACK-PORCH
DETECTOR
HIGH-FREQUENCY
BOOST CONTROL/
BYPASS
BIAS
GENERATOR
DAC2
LOWPASS
FILTER
DAC3
HFB1
HFB2
HFB3
DAC1
OUT1
Z
0
= 75
Ω
75
Ω
75
Ω
Z
0
= 75
Ω
75
Ω
75
Ω
GAIN/
LEVEL
SHIFT
LOWPASS
FILTER
LOWPASS
FILTER
OUT2
Z
0
= 75
Ω
75
Ω
75
Ω
Z
0
= 75
Ω
75
Ω
75
Ω
OUT3
Z
0
= 75
Ω
75
Ω
75
Ω
Z
0
= 75
Ω
75
Ω
75
Ω
GAIN/
LEVEL
SHIFT
GAIN/
LEVEL
SHIFT
Functional Diagram
Set-Top Boxes/HDR/DVD
Game Consoles
Camcorders
Composite, Component,
S-Video Output for
NTSC, PAL, SDTV