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General Description
The MAX7449, 3-channel, buffered video reconstruction filter is ideal for anti-aliasing and digital-to-analog
converter (DAC)-smoothing video applications or wherever analog video is reconstructed from a digital data
stream (such as cable/satellite/terrestrial 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 standarddefinition 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.
Applications
Set-Top Boxes/HDRs Game Consoles
Desktop Video Editors DVD Players
Digital VCRs
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
3-Channel Video Reconstruction Filter
for RGB Component Video
________________________________________________________________ Maxim Integrated Products 1
Functional Diagram
Ordering Information
19-2990; Rev 0; 9/03
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.
EVALUATION KIT
AVAILABLE
Pin Configuration appears at end of data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX7449EUD -40°C to +85°C 14 TSSOP-EP*
V
CC
ENCODER
75Ω
0.1µF
INA
INB
INC
GND
LOWPASS
FILTER
LOWPASS
FILTER
LOWPASS
FILTER
MAX7449
EXTSYNC
DISABLE
D/A
R
0.1µF
G
D/A
0.1µF
D/A
B
OUTA
OUTB
OUTC
75Ω
75Ω
75Ω
75Ω
75Ω
*OPTIONAL CAPACITORS
*
*
*
*
*
*
75Ω
75Ω
75Ω
75Ω
75Ω
75Ω
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MAX7449
3-Channel Video Reconstruction Filter
for RGB Component Video
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +4.75V to +5.25V, CL= 0 to 20pF, RL= 75Ω to GND for DC-coupled load, RL= 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 VCC= +5V, TA= +25°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.
VCCto 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
)
Passband Response
Stopband Attenuation A
Differential Gain dG 5-step modulated staircase 0.15 0.50 %
Differential Phase
Signal-to-Noise Ratio SNR
Group Delay Deviation ∆t
Line-Time Distortion H
Field-Time Distortion V
Clamp Settling Time t
Output DC Clamp Level Channels A, B, C 1.1 1.5 1.8 V
Low-Frequency Gain Accuracy A
Low-Frequency Gain Matching A
Group Delay Matching
Channel-to-Channel Crosstalk X
Output Short-Circuit Current I
Input Leakage Current I
Input Dynamic Swing Channels A, B, C 0.9 V
SUPPLY
Supply Voltage Range V
Supply Current I
Power-Supply Rejection Ratio PSRR V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
f = 100kHz to 5MHz, relative to 100kHz,
channels A, B, C
f ≥ 27MHz 39 43 dB
SB
dθ
DIST
DIST
CLAMP
V(MATCH
t
g(MATCH)
TALK
SC
CC
CC
5-step modulated staircase 0.15 0.50 Degrees
Peak signal (2V
f = 100Hz to 50MHz
Deviation from 100kHz to 4.1MHz 11 20 ns
g
18µs, 100 IRE bar 0.3 %
130 lines, 18µs, 100 IRE bar 0.5 %
To ±1% 100 Lines
f = 100kHz -3 +3 %
V
Low-frequency channel-to-channel
matching, f = 100kHz
Low-frequency channel-to-channel
matching, f = 100kHz
f = 100kHz to 3.58MHz 60 dB
OUT_ shorted to GND or V
IN
No load 75 100 mA
= 100mV
IN
-0.75 +0.15 +0.75 dB
) to RMS noise,
P-P
CC
4.75 5.25 V
, f = 0 to 3.5MHz 40 dB
P-P
80 dB
4%
2ns
70 mA
10 µA
P-P
Page 3
MAX7449
3-Channel Video Reconstruction Filter
for RGB Component Video
_______________________________________________________________________________________ 3
Typical Operating Characteristics
(VCC= +5V, TA = +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +4.75V to +5.25V, CL= 0 to 20pF, RL= 75Ω to GND for DC-coupled load, RL= 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 VCC= +5V, TA= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
LOGIC INPUTS (DISABLE and EXTSYNC)
At 5MHz 2 kΩ
Logic-Input High Voltage V
IH
2.0 V
Logic-Input Low Voltage V
IL
0.8 V
Logic Input Current I
LOGIC
VIL = 0V (SINK), VIH = VCC (SOURCE) ±10 µA
Output Impedance During Disable Z
DISABLE
-20
-40
AMPLITUDE (dB)
-60
-80
AMPLITUDE vs. FREQUENCY
0
NORMALIZED TO 0dB
1 100
10
FREQUENCY (MHz)
MAX7449 toc01
PASSBAND AMPLITUDE vs. FREQUENCY
2.0
1.5
1.0
0.5
0
-0.5
AMPLITUDE (dB)
-1.0
-1.5
NORMALIZED TO 0dB
-2.0
0.1 10
1
FREQUENCY (MHz)
MAX7449 toc02
PHASE (DEGREES)
-100
-150
-200
200
150
100
50
0
-50
PHASE RESPONSE vs. FREQUENCY
0.1 10
1
FREQUENCY (MHz)
MAX7449 toc03
GROUP DELAY vs. FREQUENCY
100
90
80
70
GROUP DELAY (ns)
60
50
0.1 10
1
FREQUENCY (MHz)
MAX7449 toc04
250mV/div
250mV/div
2T RESPONSE (1 IRE = 7.14mV)
IN_
OUT_
200ns/div
MAX7449 toc05
IN_
250mV/div
OUT_
250mV/div
MODULATED 12.5T RESPONSE
(1 IRE = 7.14mV)
400ns/div
MAX7449 toc06
Page 4
MAX7449
3-Channel Video Reconstruction Filter
for RGB Component Video
4 _______________________________________________________________________________________
Pin Description
SUPPLY CURRENT vs. TEMPERATURE
MAX7449 toc07
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
603510-15
90
100
110
120
80
-40 85
INPUTS BIASED TO +2V
NO LOAD
DIFFERENTIAL GAIN
MAX7449 toc08
DIFFERENTIAL PHASE (DEGREES)
1st
3rd2nd 4th 5th
6th
1st
3rd2nd 4th 5th
6th
0.2
0.3
0.1
0
-0.1
-0.2
-0.3
DIFFERENTIAL GAIN (%)
0.2
0.3
0.1
0
-0.1
-0.2
-0.3
DIFFERENTIAL PHASE
Typical Operating Characteristics (continued)
(VCC= +5V, TA = +25°C, unless otherwise noted.)
PIN NAME FUNCTION
1, 10 V
CC
+ 5V S up p l y Inp ut
2 INA C hannel A V i d eo Inp ut. U se channel A fo r the r ed ( R) vi d eo si g nal . AC - coup l e IN A w i th a ser i es 0.1µF cap aci tor .
3 INB
4 INC
5 DISABLE
6 EXTSYNC
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
to disable all
CC
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).
7, 8 GND Ground
9, 14 N.C. No Connection. Make no connection to these pins.
11 OUTC Channel C Buffer Output. This output can be either AC- or DC-coupled.
12 OUTB Channel B Buffer Output. This output can be either AC- or DC-coupled.
13 OUTA Channel A Buffer Output. This output can be either AC- or DC-coupled.
Page 5
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 reconstructs 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.
Filter
Filter Response
The reconstruction filter consists of two 2nd-order SallenKey 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).
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 output buffers drive DC loads with an output blanking level
of less than 1V.
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.
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.
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 configuration, the voltage on the video cable is always less than
1V, complying with industry-standard video requirements 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.
Power-Supply Bypassing and Layout
The MAX7449 operates from a single +5V supply.
Bypass VCCto GND with a 0.1µF capacitor. Place all
external components as close to the device as possible.
Exposed Pads
The TSSOP-EP package has an exposed pad on the
bottom of the package. This pad is electrically connected to GND and should be connected to the ground
plane for improved thermal conductivity. Do not route
signals under this package.
MAX7449
3-Channel Video Reconstruction Filter
for RGB Component Video
_______________________________________________________________________________________ 5
Pin Configuration
Chip Information
TRANSISTOR COUNT: 6300
PROCESS: BiCMOS
Table 1. Output Clamp Level
CHANNEL CLAMP LEVEL (V)
A 1.5
B 1.5
C 1.5
TOP VIEW
V
INA
INB
DISABLE
EXTSYNC
1
CC
2
3
4
MAX7449
5
6
7
14
N.C.
13
OUTA
12
OUTB
11
OUTCINC
V
10
CC
9
N.C.
GNDGND
8
TSSOP
Page 6
MAX7449
3-Channel Video Reconstruction Filter
for RGB Component Video
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages
.)
TSSOP 4.4mm BODY.EPS
PACKAGE OUTLINE, TSSOP, 4.40 MM BODY
EXPOSED PAD
21-0108
1
C
1
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