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KIT
ATION
EVALU
E
BL
AVAILA
Triple-Channel Video Reconstruction Filter and
Buffer for Composite and Y/C Outputs
General Description
The MAX7453 is a low-cost, triple-channel video recon-
struction filter for S-video and CVBS video-signal appli-
cations. This device is ideal for anti-aliasing and DAC
smoothing video applications such as set-top boxes,
DVD players, hard-disk recorders (HDRs), and personal
video recorders. This filter operates from a single +5V
supply. It is optimized for NTSC, PAL, and standard-defi-
nition TV (SDTV) video systems.
Each channel consists of a lowpass filter and an output
buffer capable of driving one (YOUT, COUT) or two
(CVOUT) standard 150Ω video loads. The output buffers
can drive either an AC or a DC load such that the blank-
ing level voltage after the backmatch resistor is less than
1V. The Y and C video inputs are summed to produce
the composite video output. The MAX7453 has a maxi-
mally flat frequency response.
The MAX7453 is available in an 8-pin SO package and is
fully specified over the commercial (0°C to +70°C) tem-
perature range.
Features
♦
Triple-Channel Filter and Buffer for CVBS and
Y/C (S-Video) Video Signals
♦
Filter Response Ideal for NTSC, PAL, and
Interlaced SDTV Signals
♦
42dB (typ) Stopband Attenuation at 27MHz
♦
-0.3dB (typ) Passband Response
♦
♦
♦
♦
<1V Blanking Level Allows DC-Coupled Output
CVOUT Drives Two 150Ω Video Loads
YOUT and COUT Drive One 150Ω Video Load
+5V Single-Supply Voltage
MAX7453
♦
8-Pin SO Package
Ordering Information
PART
MAX7453CSA
TEMP RANGE
0°C to +70°C
PIN-PACKAGE
8 SO
Applications
Set-Top Boxes/HDRs/DVDs
Security Cameras/Digital Cameras
Game Consoles
Digital VCRs
Every Composite, S-Video Output for NTSC,
PAL, and SDTV
GND
3
CIN 4
Pin Configuration
TOP VIEW
YIN 1
N.C. 2
8
7
YOUT
V
CC
CVOUT
COUT
MAX7453
6
5
SO
Functional Diagram
V
CC
*
ENCODER
D/A
YIN
LOWPASS
FILTER
+6dB
YOUT
*
MAX7453
Σ
+6dB
CVOUT
*
D/A
CIN
LOWPASS
FILTER
GND
+6dB
COUT
*
________________________________________________________________
Maxim Integrated Products
1
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.
Triple-Channel Video Reconstruction Filter and
Buffer for Composite and Y/C Outputs
MAX7453
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ...........................................................................+6V
All Other Pins to GND.................................-0.3V to (V
CC
+ 0.3V)
Maximum Current into Any Pin Except V
CC
and GND .....±50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO ....................................................................522.8mW
Operating Temperature Range...............................0°C to +70°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= +5V ±5%, C
L
= 0 to 20pF, all loads to GND for DC-couple, all loads to V
CC
/ 2 for AC-couple, C
YIN
= C
CIN
= 0.1µF,
R
YOUT
= 150Ω, R
COUT
= 150Ω, R
CVOUT
= 75Ω, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
Passband Response
Stopband Attenuation
Chroma/Luma Gain
Differential Gain
Differential Phase
Signal-to-Noise Ratio
Line-Time Distortion
Field-Time Distortion
Clamp Settling Time
Output DC Clamp Level
Low-Frequency Gain Accuracy
Group-Delay Deviation
Group-Delay Matching
Channel-to-Channel Crosstalk
Input Leakage Current
Input Dynamic Swing
SUPPLY
Supply Voltage Range
Supply Current
Power-Supply Rejection Ratio
V
CC
I
CC
PSRR
V
CC
= +5.25V, no load
V
IN
= 100mV
P-P
, f = 0 to 3.5MHz
4.75
65
33
5.25
85
V
mA
dB
A
V
Δt
g
t
g(MATCH)
X
TALK
I
IN
Y
INP-P
C
INP-P
dG
dθ
SNR
H
DIST
V
DIST
A
SB
SYMBOL
f = 27MHz
f = 3.58MHz, reference to CVOUT at 336kHz
5-step modulated staircase
5-step modulated staircase
Peak signal (2V
P-P
) to RMS noise,
f = 100Hz to 50MHz
18µs, 100IRE bar
130 lines, 18µs, 100IRE bar
To ±1%
YOUT
CVOUT
COUT
f = 100kHz, relative to 6dB
Deviation from 100kHz to 4.1MHz
Low-frequency channel-to-channel matching,
f = 100kHz for YOUT and COUT
f = 100kHz to 3.58MHz
0.60
0.60
1.44
-3.0
8
2
61
10
1.2
0.9
300
0.8
0.8
1.6
0.95
0.95
1.95
+2.0
16
%
ns
ns
dB
µA
V
P-P
V
67
CONDITIONS
f = 100kHz to 4.2MHz, relative to 100kHz
MIN
-0.6
39
96
TYP
-0.27
42
98
0.15
0.15
73
0.3
0.5
100
0.5
0.5
MAX
0
UNITS
dB
dB
%
%
Degrees
dB
%
%
Lines
2
_______________________________________________________________________________________
Triple-Channel Video Reconstruction Filter and
Buffer for Composite and Y/C Outputs
Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
MAX7453
AMPLITUDE vs. FREQUENCY
MAX7453 toc01
PASSBAND AMPLITUDE vs. FREQUENCY
MAX7453 toc02
PHASE RESPONSE vs. FREQUENCY
0
-40
PHASE (DEGREES)
-80
-120
-160
-200
-240
MAX7453 toc03
10
0
-10
AMPLITUDE (dB)
-20
-30
-40
-50
-60
-70
-80
1
10
FREQUENCY (MHz)
NORMALIZED TO 0dB
1.0
0.5
0
AMPLITUDE (dB)
-0.5
-1.0
-1.5
-2.0
-2.5
NORMALIZED TO 0dB
-3.0
40
-280
0.1
1
FREQUENCY (MHz)
10
0.1
1
FREQUENCY (MHz)
10
100
GROUP DELAY vs. FREQUENCY
MAX7453 toc04
2T RESPONSE (1IRE = 7.4mV)
MAX7453 toc05
MODULATED 12.5T RESPONSE
(1IRE = 7.14mV)
MAX7453 toc06
90
85
80
GROUP DELAY (ns)
75
70
65
60
55
50
45
40
0.1
1
FREQUENCY (MHz)
MEASURE AT TERMINATION
YIN
500mV/div
YIN
200mV/div
MEASURE AT
TERMINATION
YOUT
500mV/div
YOUT
200mV/div
100ns/div
400ns/div
10
SUPPLY CURRENT vs. TEMPERATURE
DIFFERENTIAL GAIN (%)
MAX7453 toc07
68
66
SUPPLY CURRENT (mA)
64
62
60
58
56
54
52
50
-40
-15
10
35
60
MAX7453 toc08
70
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
1st
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
1st
2nd
2nd
DIFFERENTIAL GAIN
MULTIBURST RESPONSE
MAX7453 toc09
YIN
500mV/div
3rd
4th
5th
6th
MEASURED AT TERMINATION
YOUT
500mV/div
DIFFERENTIAL PHASE (DEGREES)
DIFFERENTIAL PHASE
85
10μs/div
3rd
4th
5th
6th
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Triple-Channel Video Reconstruction Filter and
Buffer for Composite and Y/C Outputs
MAX7453
Pin Description
PIN
1
2
3
4
5
6
7
8
NAME
YIN
N.C.
GND
CIN
COUT
CVOUT
V
CC
YOUT
FUNCTION
Luma (Y) Input
No Connection. No internal connection.
Ground
Chroma (C) Input
Chroma (C) Output
Composite Video Output
5V Power Supply
Luma (Y) Output
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 to
set 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 MAX7453. This input capacitor stores a DC level
such that the outputs are clamped to the appropriate
DC voltage level.
Detailed Description
The primary function of the MAX7453 is to filter and
buffer the encoder DAC outputs that contain digital
video information in applications such as set-top boxes,
HDRs, DVD players, and digital VCRs. This device
reconstructs and cleans up analog video signals. The
MAX7453 consists of a lowpass filter and a +6dB-gain
output video buffer. The luma (YIN) and chroma (CIN)
video inputs are summed internally to provide the com-
posite (CVOUT) video output.
These devices operate from a single +5V supply. The
filters have a nominal cutoff frequency optimized for
NTSC, PAL, and SDTV.
Output Considerations
The outputs of the MAX7453 are typically connected to
a 75Ω series back-match resistor followed by the video
cable. Because of the inherent divide-by-two of this con-
figuration, 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 MAX7453 operates from a single +5V supply.
Bypass V
CC
to GND with a 0.1µF capacitor. Place all
external components as close to the device as possible.
The maximum power dissipation listed in the
Absolute
Maximum Ratings
section assumes that the PC board is
a multilayer board with ground and power planes.
Filter
Filter Response
The reconstruction filter consists of two 2nd-order
Sallen-Key stages. The Butterworth-type response fea-
tures a maximally flat passband for NTSC and PAL
bandwidths. The stopband offers 42dB (typ) of attenua-
tion at sampling frequencies of 27MHz and above (see
the
Typical Operating Characteristics).
Chip Information
TRANSISTOR COUNT: 4100
PROCESS: BiCMOS
Output Buffer
The YOUT and COUT buffers have a fixed +6dB gain
capable of driving one standard 150Ω video load with a
2V
P-P
signal. The CVOUT buffer has a fixed +6dB gain,
capable of driving two 150Ω video loads. The MAX7453
can drive an AC load or drive the video load directly
without using the large output capacitor. The output
buffer of all the channels drives a DC load with an out-
put blanking level of less than 1V.
4
_______________________________________________________________________________________
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