19-2990; Rev 1; 4/06
KIT
ATION
EVALU
BLE
AVAILA
3-Channel Video Reconstruction Filter
for RGB Component Video
General Description
Features
♦
3-Channel Filter and Buffer for RGB Video Signals
♦
External Sync Signal Input
♦
Filter Response Ideal for NTSC, PAL, and
Interlaced SDTV Video Signals
♦
43dB (typ) Stopband Attenuation at 27MHz
♦
±0.75dB (max) Passband Ripple at 5MHz
♦
Blanking Level Voltage on Output <1V
♦
Each Channel Drives Two 150Ω Video Loads
♦
+5V Single-Supply Voltage
♦
Small 14-Pin TSSOP Package
MAX7449
The MAX7449, 3-channel, buffered video reconstruc-
tion filter is ideal for anti-aliasing and digital-to-analog
converter (DAC)-smoothing video applications or wher-
ever analog video is reconstructed from a digital data
stream (such as cable/satellite/terrestrial set-top boxes,
DVD players, hard-disk recorders (HDRs), and person-
al 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 150Ω video loads.
The MAX7449 processes component RGB video signals.
The output video buffers have a fixed gain of +6dB. The
output video drivers can be disabled with an external pin.
The MAX7449 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.
Ordering Information
PART
TEMP
RANGE
-40°C to
+85°C
PIN-
PACKAGE
14 TSSOP-EP*
PACKAGE
CODE
U14E-3
Applications
Set-Top Boxes/HDRs
Desktop Video Editors
Digital VCRs
Game Consoles
DVD Players
MAX7449EUD
*EP
= Exposed pad.
Pin Configuration appears at end of data sheet.
Functional Diagram
V
CC
ENCODER
75Ω
0.1µF
R
D/A
*
INA
LOWPASS
FILTER
OUTA
75Ω
*
75Ω
75Ω
75Ω
0.1µF
G
D/A
*
INB
LOWPASS
FILTER
OUTB
75Ω
*
75Ω
75Ω
75Ω
0.1µF
B
D/A
INC
LOWPASS
FILTER
OUTC
75Ω
*
*
75Ω
75Ω
MAX7449
GND
EXTSYNC
DISABLE
*OPTIONAL CAPACITORS
________________________________________________________________
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.
3-Channel Video Reconstruction Filter
for RGB Component Video
MAX7449
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)
TSSOP-EP (derate 20.8mW/°C above +70°C) ...........1667mW
Operating Temperature Range ...........................-40°C to +85°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
= +4.75V to +5.25V, C
L
= 0 to 20pF, R
L
= 75Ω to GND for DC-coupled load, R
L
= 75Ω to V
CC
/ 2 for AC-coupled load, C
IN_
=
0.1µF, GAIN = +6dB, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V, T
A
= +25°C.)
PARAMETER
Passband Response
Stopband Attenuation
Differential Gain
Differential Phase
Signal-to-Noise Ratio
Group Delay Deviation
Line-Time Distortion
Field-Time Distortion
Clamp Settling Time
Output DC Clamp Level
Low-Frequency Gain Accuracy
Low-Frequency Gain Matching
Group Delay Matching
Channel-to-Channel Crosstalk
Output Short-Circuit Current
Input Leakage Current
Input Dynamic Swing
SUPPLY
Supply Voltage Range
Supply Current
Power-Supply Rejection Ratio
V
CC
I
CC
PSRR
No load
V
IN
= 100mV
P-P
, f = 0 to 3.5MHz
4.75
75
40
5.25
100
V
mA
dB
A
V
A
V(MATCH)
t
g(MATCH)
X
TALK
I
SC
I
IN
Channels A, B, C
A
SB
dG
dθ
SNR
∆t
g
H
DIST
V
DIST
t
CLAMP
SYMBOL
CONDITIONS
f = 100kHz to 5MHz, relative to 100kHz,
channels A, B, C
f
≥
27MHz
5-step modulated staircase
5-step modulated staircase
Peak signal (2V
P-P
) to RMS noise,
f = 100Hz to 50MHz
Deviation from 100kHz to 4.1MHz
18µs, 100 IRE bar
130 lines, 18µs, 100 IRE bar
To ±1%
Channels A, B, C
f = 100kHz
Low-frequency channel-to-channel
matching, f = 100kHz
Low-frequency channel-to-channel
matching, f = 100kHz
f = 100kHz to 3.58MHz
OUT_ shorted to GND or V
CC
2
60
70
10
0.9
1.1
-3
430
1.5
1.8
+3
4
MIN
-0.75
39
TYP
+0.15
43
0.15
0.15
80
11
20
0.3
0.5
0.50
0.50
MAX
+0.75
UNITS
dB
dB
%
Degrees
dB
ns
%
%
Lines
V
%
%
ns
dB
mA
µA
V
P-P
2
_______________________________________________________________________________________
3-Channel Video Reconstruction Filter
for RGB Component Video
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.75V to +5.25V, C
L
= 0 to 20pF, R
L
= 75Ω to GND for DC-coupled load, R
L
= 75Ω to V
CC
/ 2 for AC-coupled load, C
IN_
=
0.1µF, GAIN = +6dB, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V, T
A
= +25°C.)
PARAMETER
Output Impedance During Disable
Logic-Input High Voltage
Logic-Input Low Voltage
Logic Input Current
SYMBOL
Z
DISABLE
V
IH
V
IL
I
LOGIC
V
IL
= 0V (SINK), V
IH
= V
CC
(SOURCE)
At 5MHz
2.0
0.8
±10
CONDITIONS
MIN
TYP
2
MAX
UNITS
kΩ
V
V
µA
LOGIC INPUTS (DISABLE and EXTSYNC)
MAX7449
Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
AMPLITUDE vs. FREQUENCY
MAX7449 toc01
PASSBAND AMPLITUDE vs. FREQUENCY
MAX7449 toc02
PHASE RESPONSE vs. FREQUENCY
150
100
PHASE (DEGREES)
50
0
-50
-100
-150
MAX7449 toc03
2.0
1.5
1.0
200
0
AMPLITUDE (dB)
AMPLITUDE (dB)
NORMALIZED TO 0dB
-20
0.5
0
-0.5
-1.0
-1.5
-40
-60
-80
1
10
FREQUENCY (MHz)
100
NORMALIZED TO 0dB
-2.0
0.1
1
FREQUENCY (MHz)
10
-200
0.1
1
FREQUENCY (MHz)
10
GROUP DELAY vs. FREQUENCY
MAX7449 toc04
2T RESPONSE (1 IRE = 7.14mV)
MAX7449 toc05
MODULATED 12.5T RESPONSE
(1 IRE = 7.14mV)
MAX7449 toc06
100
90
GROUP DELAY (ns)
IN_
250mV/div
IN_
80
250mV/div
70
OUT_
OUT_
60
250mV/div
50
0.1
1
FREQUENCY (MHz)
10
200ns/div
400ns/div
250mV/div
_______________________________________________________________________________________
3
3-Channel Video Reconstruction Filter
for RGB Component Video
MAX7449
Typical Operating Characteristics (continued)
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX7449 toc07
DIFFERENTIAL GAIN
DIFFERENTIAL PHASE (DEGREES) DIFFERENTIAL GAIN (%)
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
3rd
4th
5th
6th
2nd
3rd
4th
5th
6th
MAX7449 toc08
120
INPUTS BIASED TO +2V
NO LOAD
SUPPLY CURRENT (mA)
110
100
DIFFERENTIAL PHASE
90
80
-40
-15
10
35
60
85
TEMPERATURE (°C)
Pin Description
PIN
1, 10
2
3
4
5
6
7, 8
9, 14
11
12
13
NAME
V
CC
INA
INB
INC
DISABLE
EXTSYNC
GND
N.C.
OUTC
OUTB
OUTA
+5V Supply Input
Channel A Video Input. Use channel A for the red (R) video signal. AC-couple INA with a series 0.1µF capacitor.
Channel B Video Input. Use channel B for the green (G) video signal. AC-couple INB with a series 0.1µF
capacitor.
Channel C Video Input. Use channel C for the blue (B) video signal. AC-couple INC with a series 0.1µF
capacitor.
Disable Logic Input. Connect DISABLE to GND for normal operation. Connect DISABLE to V
CC
to disable all
buffer outputs and put them in a high-impedance state.
External Sync Input. Use TTL logic levels. A logic high enables the DC restore loop and clamps the output
voltages to +1.5V (typ).
Ground
No Connection. Make no connection to these pins.
Channel C Buffer Output. This output can be either AC- or DC-coupled.
Channel B Buffer Output. This output can be either AC- or DC-coupled.
Channel A Buffer Output. This output can be either AC- or DC-coupled.
FUNCTION
4
_______________________________________________________________________________________
3-Channel Video Reconstruction Filter
for RGB Component Video
Detailed Description
The MAX7449 filters and buffers video-encoder DAC
outputs in applications such as set-top boxes, HDRs,
DVD players, and digital VCRs. The MAX7449 recon-
structs and cleans up component RGB analog video
signals. Each channel consists of a lowpass filter and
an output video buffer that drives two standard 150Ω
video loads.
This device operates from a single +5V supply and has
a nominal cutoff frequency of 5MHz optimized for
NTSC, PAL, and SDTV.
Applications Information
Input Considerations
Use 0.1µF ceramic capacitors to AC-couple the inputs.
These input capacitors store a DC level so the outputs
are clamped to an appropriate DC voltage level. The
MAX7449 allows R, G, or B video signals to be processed
by any channel. G must not have sync information.
MAX7449
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 voltage on the video cable is always less than
1V, complying with industry-standard video require-
ments such as the European SCART standard (which
allows up to 2V of DC 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.
Filter
Filter Response
The reconstruction filter consists of two 2nd-order Sallen-
Key stages. The Butterworth-type response features a
maximally flat passband for NTSC and PAL bandwidths.
The stopband offers at least 43dB (typ) of attenuation at
a sampling frequency of
≥27MHz
(see the
Typical
Operating Characteristics).
Power-Supply Bypassing and Layout
The MAX7449 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.
Output Buffers
Each output buffer has a fixed gain of +6dB and can
drive two 150Ω video loads with a 2V
P-P
signal. The
MAX7449 can drive an AC load or drive the video load
directly without using a large output capacitor. The out-
put buffers drive DC loads with an output blanking level
of less than 1V.
Exposed Pads
The TSSOP-EP package has an exposed pad on the
bottom of the package. This pad is electrically connect-
ed to GND and should be connected to the ground
plane for improved thermal conductivity. Do not route
signals under this package.
Output Clamp Level
When a sync pulse is detected on EXTSYNC, the DC
restore loop is activated for channels A, B, and C. The
function of the loop is to set the DC level of the video
signal to the desired level. See Table 1 for clamp levels.
Pin Configuration
TOP VIEW
Table 1. Output Clamp Level
CHANNEL
A
B
C
CLAMP LEVEL (V)
1.5
1.5
1.5
V
CC
1
INA
INB
2
3
14 N.C.
13 OUTA
12 OUTB
INC 4
DISABLE 5
EXTSYNC 6
GND 7
MAX7449
11 OUTC
10 V
CC
9
8
N.C.
GND
TSSOP
Chip Information
TRANSISTOR COUNT: 6300
PROCESS: BiCMOS
_______________________________________________________________________________________
5
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