19-3790; Rev 1; 9/05
Single-Channel Video Reconstruction Filters
and Buffers
General Description
The MAX7462/MAX7463 single-channel, standard-defini-
tion, integrated video reconstruction filters and buffers
are ideal for anti-aliasing and digital-to-analog smoothing
video applications or wherever analog video is recon-
structed from digital data (such as cable/satellite/terres-
trial set-top boxes and DVRs).
The MAX7462 includes a disable function, which
places the output in a high-impedance state allowing
multiplexing of multiple output signals. It also has an
external gain control that sets the output buffer gain to
either +6dB or +9.5dB. The higher gain setting allows a
lower DAC output signal than the standard 1V
P-P
sig-
nal. The MAX7463 output buffer has a fixed gain of
+6dB.
The MAX7462/MAX7463 operate from a single +5V
supply and have a flat passband out to 5MHz with a
stopband attenuation of -43dB (typ) at 27MHz.
These devices can drive two standard 150Ω AC-cou-
pled or DC-coupled video loads. The output black level
of the MAX7462/MAX7463 is less than 1V for DC-cou-
pled outputs.
The MAX7462 is available in an 8-pin µMAX
®
package
and an 8-pin SO package. The MAX7463 is available in
an 8-pin SO package. All devices are specified over
the 0°C to +85°C temperature range.
Features
♦
Standard-Definition CVBS Video Reconstruction
Filters and Buffers
♦
Passband: -0.05dB at 5MHz
♦
Stopband: -43dB at 27MHz
♦
Selectable Gain: +6dB and +9.5dB (MAX7462)
♦
Output Disable (MAX7462)
♦
Drives 2V
P-P
into Two 150Ω Video Loads
♦
Output Black Level < 1V for DC-Coupled Output
♦
Very Small µMAX and SO Packages
MAX7462/MAX7463
Ordering Information
PART
MAX7462UUA*
MAX7462USA
MAX7463USA
PIN-
PACKAGE
8 µMAX
8 SO
8 SO
BUFFER GAIN
(dB)
+6/+9.5
selectable
+6/+9.5
selectable
+6 fixed
OUTPUT
DISABLE
Yes
Yes
No
Applications
Cable/Satellite/Terrestrial Set-Top Boxes
DVRs
Hard-Disk Recorders
Note:
All parts are specified over the 0°C to +85°C temperature
range.
*Future
product—contact factory for availability.
Pin Configurations appear at end of data sheet.
Functional Diagram
+5V
V
CC
MAX7462
75Ω
*
220µF
Z
O
= 75Ω
0.1µF
DAC
IN
LOWPASS
FILTER
+6dB/+9.5dB
OUT
75Ω
75Ω
*
220µF
Z
O
= 75Ω
GND
GAIN
*OPTIONAL
DISABLE
75Ω
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
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.
Single-Channel Video Reconstruction Filters
and Buffers
MAX7462/MAX7463
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ........................................................................+6.0V
All Other Pins to GND ...-0.3V to the lower of (V
CC
+ 0.3V) and +6V
Maximum Current into Any Pin Except V
CC
and GND .....±50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) …...... 362mW
8-Pin SO (derate 5.9mW/°C above +70°C) .......... 470.6mW
Operating Temperature Range...............................0°C to +85°C
Storage Temperature Range .............................-65°C to +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, R
L
= 75Ω, C
IN
= 0.1µF, gain = +6dB,
DISABLE
= V
CC
(MAX7462), T
A
=T
MIN
to T
MAX
, unless other-
wise noted. Typical values are at V
CC
= +5V, and T
A
= +25°C.)
PARAMETER
Passband Response
Stopband Attenuation
Output Dynamic Swing
Output Sync Tip Clamp Level
Group Delay Deviation
Differential Gain
Differential Phase
Signal-to-Noise Ratio
Low-Frequency Gain Accuracy
Line Time Distortion
Field Time Distortion
Power-Supply Rejection Ratio
Supply Current
f
≥
27MHz
Gain = GND (MAX7462)
After termination (Note 1)
f = 100kHz to 4.2MHz
Five-step modulated staircase
Five-step modulated staircase
Output signal (2V
P-P
) to RMS noise (100Hz to 5MHz)
f =100kHz, relative to a gain of +6dB
18µs, 100 IRE bar
130 lines, 18µs, 100 IRE bar
V
IN
= 100mV
P-P
, f = 100kHz
No load
-3
0.1
0.1
35
25
35
0.30
CONDITIONS
f = 100kHz to 5MHz, relative to 100kHz
MIN
-0.65
39
TYP
-0.05
43
2.0
0.45
11
0.15
0.15
75
+3
2.4
0.55
MAX
+0.65
UNITS
dB
dB
V
P-P
V
ns
%
Degrees
dB
%
%
%
dB
mA
Note 1:
Measured after 75Ω back-match resistor. Assume a 75Ω termination resistor.
2
_______________________________________________________________________________________
Single-Channel Video Reconstruction Filters
and Buffers
Typical Operating Characteristics
(V
CC
= +5V ±5%, C
L
= 0 to 20pF, R
L
= 75Ω, C
IN
= 0.1µF, gain = +6dB,
DISABLE
= V
CC
(MAX7462), T
A
=T
MIN
to T
MAX
, unless other-
wise noted. Typical values are at V
CC
= +5V, and T
A
= +25°C.)
PASSBAND AMPLITUDE
vs. FREQUENCY
AMPLITUDE vs. FREQUENCY
0
MAX7462/63 toc01
MAX7462/MAX7463
1.5
1.0
AMPLITUDE (dB)
0.5
0
-0.5
-1.0
-1.5
AMPLITUDE (dB)
-20
-40
-60
NORMALIZED TO 0dB
-80
0.1
1
10
100
FREQUENCY (MHz)
NORMALIZED TO 0dB
-2.0
0.1
1
FREQUENCY (MHz)
10
PHASE RESPONSE
vs. FREQUENCY
MAX7462/63 toc03
GROUP DELAY vs. FREQUENCY
MAX7462/63 toc04
200
150
100
PHASE (DEGREES)
50
0
-50
-100
100
90
GROUP DELAY (ns)
80
70
60
-150
-200
0.1
1
FREQUENCY (MHz)
10
50
0.1
1
FREQUENCY (MHz)
10
2T RESPONSE
MAX7462/63 toc05
MODULATED 12.5T RESPONSE
MAX7462/63 toc06
OUT
250mV/div
IN
250mV/div
200ns/div
200ns/div
_______________________________________________________________________________________
MAX7462/63 toc02
2.0
OUT
250mV/div
IN
250mV/div
3
Single-Channel Video Reconstruction Filters
and Buffers
MAX7462/MAX7463
Typical Operating Characteristics (continued)
(V
CC
= +5V ±5%, C
L
= 0 to 20pF, R
L
= 75Ω, C
IN
= 0.1µF, gain = +6dB,
DISABLE
= V
CC
(MAX7462), T
A
=T
MIN
to T
MAX
, unless other-
wise noted. Typical values are at V
CC
= +5V, and T
A
= +25°C.)
SUPPLY CURRENT vs. TEMPERATURE
MAX7462/63 toc07
DIFFERENTIAL GAIN
DIFFERENTIAL GAIN (%)
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
1
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
1
2
3
4
5
6
7
2
3
4
5
6
7
MAX7462/63 toc08
40
V
IN
= +2V
NO LOAD
SUPPLY CURRENT (mA)
30
20
10
0
17
34
51
68
85
TEMPERATURE (°C)
DIFFERENTIAL PHASE (deg)
DIFFERENTIAL PHASE
MULTIBURST RESPONSE
MAX7462/63 toc09
OUT RESPONSE TO A FIELD
SQUARE WAVE
MAX7462/63 toc10
OUT
250mV/div
OUT
500mV/div
IN
250mV/div
IN
500mV/div
10µs/div
2ms/div
DISABLE TURN-ON TIME
MAX7462/63 toc11
DISABLE TURN-OFF TIME
MAX7462/63 toc12
OUT
1V/div
OUT
1V/div
GND
GND
DISABLE
2V/div
GND
100ns/div
DISABLE
2V/div
GND
100ns/div
4
_______________________________________________________________________________________
Single-Channel Video Reconstruction Filters
and Buffers
Pin Description
PIN
MAX7462
1
2
3, 4, 5
—
6
7
8
MAX7463
1
—
3
2, 4, 5, 6
—
7
8
NAME
IN
GAIN
GND
N.C.
DISABLE
V
CC
OUT
FUNCTION
Video Input. AC-couple IN with a series 0.1µF capacitor.
Gain Control Input. Connect GAIN to GND for a gain of +6dB (+2V/V). Connect GAIN to V
CC
for a gain of +9.5dB (+3V/V).
Ground
No Connection. Not internally connected. Connect to GND for better performance.
Disable Input. Connect to V
CC
to enable the output buffer (normal operation). Connect to GND
to put the output buffer in a high-impedance state.
+5V Supply Input
Buffer Output. This output can be either AC- or DC-coupled. Use at minimum a 220µF
capacitor for AC-coupled loads.
MAX7462/MAX7463
Detailed Description
The MAX7462/MAX7463 filters and buffers the analog
CVBS video outputs of DAC video-encoders in applica-
tions such as set-top boxes, hard-disk recorders, DVD
players, and digital VCRs. The MAX7462/MAX7463 con-
sist of a lowpass filter and an output video buffer that can
drive two standard 150Ω video loads. These devices
operate from a single +5V supply and have a bandwidth
optimized for interlaced NTSC, PAL, and SDTV.
capacitor. The output buffer can drive DC loads while
maintaining an output blanking level of less than 1V. The
blanking level allows the MAX7462/MAX7463 to meet the
digital TV interface specifications for DC coupling.
Applications Information
Input Considerations
Use a 0.1µF ceramic capacitor to AC-couple the input.
The input capacitor stores a DC voltage so that the out-
put is clamped to the appropriate DC voltage level.
Filter
The reconstruction filter is a 4th-order Butterworth-type
response that features a maximally flat passband for
NTSC and PAL bandwidths. The stopband attenuation
is optimized for a video-encoder DAC sampling fre-
quency of 27MHz (see the
Typical Operating
Characteristics).
Output Considerations
The outputs are typically connected to a 75Ω series
back-match resistor followed by the video cable.
Because of the inherent divide-by-two of this configura-
tion, the blanking level on the video cable is always
less than 1V, complying with industry-standard video
requirements such as the digital TV standard (which
allows up to 1VDC on the video cable) and the
European SCART standard (which allows up to 2VDC
on the video cable). The video buffer can also drive an
AC-coupled video load. Good video performance is
achieved with an output capacitor as low as 220µF.
Output Buffer
The output buffer can drive two 150Ω video loads with
a 2V
P-P
signal. For the MAX7462, the output buffer gain
is selectable between +6dB and +9.5dB by using GAIN
(see
Table 1). The MAX7463 has a fixed gain of +6dB.
The MAX7462/MAX7463 can drive an AC load or drive
the video load directly without using a large output
Power-Supply Bypassing and Layout
The MAX7462/MAX7463 operate from a single +5V
supply. Bypass V
CC
to GND with a 0.1µF capacitor. In
addition, it is sometimes advantageous to connect a
10µF capacitor within the general vicinity of the video
circuitry. Place all other external components as close
to the device as possible.
Table 1. Gain Setting Control (MAX7462)
GAIN
GND
V
CC
BUFFER GAIN (dB)
+6
+9.5
_______________________________________________________________________________________
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