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19-2989; Rev 0; 10/03
KIT ATION EVALU E AILABL AV
4-Channel RGB Video Filter with Asynchronous CVBS Input
Features
o 4-Channel Filter and Buffer for RGB and CVBS Video Signals o Filter Response Ideal for NTSC, PAL, and Interlaced SDTV Video Signals o 43dB (typ) Stopband Attenuation at 27MHz o 0.75dB (max) Passband Ripple Out to 5MHz o Blanking Level Voltage on Cable <1V o Each Channel Drives Two 150 Video Loads o +5V Single-Supply Voltage o Small 14-Pin TSSOP Package
General Description
The MAX7448, 4-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 150 video loads. The MAX7448 processes RGB and asynchronous CVBS video signals. The output video buffers have a fixed gain of +6dB. The channel used for CVBS video has high-frequency boost circuitry, which provides picture sharpness with +1.2dB of gain boost without degradation in the stopband. The output video drivers can be disabled with an external pin. The MAX7448 is available in a 14-pin TSSOP package with an exposed pad, and is specified over the -40C to +85C extended temperature range.
MAX7448
Ordering Information
PART MAX7448EUD TEMP RANGE -40C to +85C PIN-PACKAGE 14 TSSOP-EP*
*EP = Exposed pad.
Applications
Set-Top Boxes/HDRs Game Consoles Desktop Video Editors DVD Players Digital VCRs
Pin Configuration appears at end of data sheet.
Functional Diagram
VCC ENCODER 0.1F G D/A (WITH SYNC) INA LOWPASS FILTER SYNC DETECTOR OUTA 75 * 75 75 0.1F R D/A * INB LOWPASS FILTER OUTB 75 75 0.1F B D/A INC LOWPASS FILTER OUTC 75 75 IND LOWPASS FILTER SYNC DETECTOR OUTD 75 * * * * * 75 75 75 75 75 * 75 75 75
0.1F CVBS D/A (WITH SYNC)
MAX7448
GND DISABLE
*OPTIONAL CAPACITORS
________________________________________________________________ Maxim Integrated Products
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4-Channel RGB Video Filter with Asynchronous CVBS Input MAX7448
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................................+6V All Other Pins to GND.................................-0.3V to (VCC + 0.3V) Maximum Current into Any Pin Except VCC and GND .....50mA Continuous Power Dissipation (TA = +70C) TSSOP-EP (derate 20.8mW/C above +70C) ...........1667mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10s) .................................+300C
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
(VCC = +5V 5%, CL = 0 to 20pF, RL = 75 to GND for DC-coupled load, RL = 75 to VCC / 2 for AC-coupled load, CIN_ = 0.1F, GAIN = +6dB,TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25C.)
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 VCC ICC PSRR No load VIN = 100mVP-P, f = 0 to 3.5MHz 4.75 100 40 5.25 140 V mA dB AV AV(MATCH) tg(MATCH) XTALK ISC IIN Channels A, D Channels B, C ASB dG d SNR tg HDIST VDIST tCLAMP SYMBOL CONDITIONS f = 100kHz to 5MHz, relative to 100kHz f 27MHz 5-step modulated staircase 5-step modulated staircase Peak signal (2VP-P) to RMS noise, f = 100Hz to 50MHz Deviation from 100kHz to 4.1MHz 18s, 100 IRE bar 130 lines, 18s, 100 IRE bar To 1% Channels A, D Channels 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 VCC 2 60 70 10 1.2 0.9 0.6 1.1 -3 0.9 1.5 Channels A, B, C Channel D Channels A, B, C Channel D MIN +0.75 +0.9 39 TYP +0.15 +1.2 43 0.15 0.15 80 11 17 20 30 0.3 0.5 100 1.1 1.8 +3 4 0.50 0.50 MAX +0.75 +1.5 UNITS dB dB % Degrees dB ns % % Lines V % % ns dB mA A VP-P
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4-Channel RGB Video Filter with Asynchronous CVBS Input
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V 5%, CL = 0 to 20pF, RL = 75 to GND for DC-coupled load, RL = 75 to VCC / 2 for AC-coupled load, CIN_ = 0.1F, GAIN = +6dB, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25C.)
PARAMETER DISABLE Output Impedance during Disable Disable Logic-Input High Voltage Disable Logic-Input Low Voltage Disable Logic-Input Current ZDISABLE VIH VIL IDISABLE VIL = 0V (sink), VIH = VCC (source) At 5MHz 2.0 0.8 10 2 k V V A SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX7448
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
AMPLITUDE vs. FREQUENCY
MAX7448 toc01
PASSBAND AMPLITUDE vs. FREQUENCY
MAX7448 toc02
PHASE RESPONSE vs. FREQUENCY
150 100 PHASE (DEGREES) 50 0 -50 -100 -150
MAX7448 toc03
2.0 1.5 1.0 HIGH-FREQUENCY BOOST
200
0
AMPLITUDE (dB)
AMPLITUDE (dB)
-20
0.5 0 -0.5 FLAT PASSBAND RESPONSE -1.0 -1.5
-40
-60 NORMALIZED TO 0dB -80 1 10 FREQUENCY (MHz) 100
NORMALIZED TO 0dB -2.0 0.1 1 FREQUENCY (MHz) 10 -200 0.1 1 FREQUENCY (MHz) 10
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4-Channel RGB Video Filter with Asynchronous CVBS Input MAX7448
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
GROUP DELAY vs. FREQUENCY
MAX7448 toc04
2T RESPONSE (1 IRE = 7.14mV)
MAX7448 toc05
MODULATED 12.5T RESPONSE (1 IRE = 7.14mV)
MAX7448 toc06
100
90 GROUP DELAY (ns)
IN_ 250mV/div
IN_ 250mV/div
80
70 OUT_ 60 250mV/div 50 0.1 1 FREQUENCY (MHz) 10 200ns/div 400ns/div 250mV/div OUT_
SUPPLY CURRENT vs. TEMPERATURE
MAX7448 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
MAX7448 toc08
MULTIBURST RESPONSE
MAX7448 toc09
120 INPUTS BIASED TO +2V NO LOAD SUPPLY CURRENT (mA) 110
IN_ 250mV/div
100
DIFFERENTIAL PHASE
OUT_ 250mV/div
90
80 -40 -15 10 35 60 85 TEMPERATURE (C)
10s/div
4
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4-Channel RGB Video Filter with Asynchronous CVBS Input
Pin Description
PIN 1 2 3 4 5 6-9 10 11 12 NAME INA INB INC IND DISABLE GND VCC OUTD OUTC FUNCTION Channel A Video Input. Use channel A for the green (G with sync) video signal. AC-couple INA with a series 0.1F capacitor. Channel B Video Input. Use channel B for the red (R) video signal. AC-couple INB with a series 0.1F capacitor. Channel C Video Input. Use channel C for the blue (B) video signal. AC-couple INC with a series 0.1F capacitor. Channel D Video Input. Use channel D for a CVBS (with sync) signal. AC-couple IND with a series 0.1F capacitor. Disable Logic Input. A logic-low on DISABLE enables the output buffers. A logic-high on DISABLE disables all buffer outputs and puts them in a high-impedance state. Ground +5V Supply Input Channel D Buffer Output. This output can be either AC- or DC-coupled. Channel C Buffer Output. This output can be either AC- or DC-coupled.
MAX7448
Detailed Description
The MAX7448 filters and buffers video-encoder DAC outputs in applications such as set-top boxes, HDRs, DVD players, and digital VCRs. The MAX7448 reconstructs and cleans up analog video signals from the output of DAC video encoders. Each channel consists of a lowpass filter and an output video buffer that can drive two standard 150 video loads. The MAX7448 is designed to process R, G (with sync), B, and CVBS ASYNC video signals. The video signal processed by channel A (G video signal) requires a sync pulse. This sync pulse provides the required timing for channels A, B, and C. Channel D allows an asynchronous video signal to be processed with its own local sync separator. 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 video-encoder DAC sampling frequency of 27MHz (see the Typical Operating Characteristics). High-Frequency Boost The +1.2dB high-frequency boost on channel D (CVBS video signal) increases image sharpness by compensating for signal degradation and rolloff in the video encoder. Channels A, B, and C do not boost high-frequency signals and have a flat response over the video bandwidth.
Output Buffers
Each output buffer has a fixed gain of +6dB and can drive two 150 video loads with a 2VP-P signal. The MAX7448 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.
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4-Channel RGB Video Filter with Asynchronous CVBS Input MAX7448
Output Clamp Level
When a sync pulse is detected on channel A, the DC restore loop is activated for channel A, B, and C. Channel D's DC restore loop is activated by the sync pulse on channel D. The function of the loop is to set the DC level of the video signal to the specified level of the signal type (R, G, B, CVBS). See Table 1 for clamp levels and sync sources.
Power-Supply Bypassing and Layout
The MAX7448 operates from a single +5V supply. Bypass VCC to GND with a 0.1F 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.
Table 1. Output Clamp Level and Sync Source
CHANNEL A B C D CLAMP LEVEL (V) 0.9 1.5 1.5 0.9 SYNC SOURCE Channel A Channel A Channel A Channel D
Pin Configuration
TOP VIEW
INA 1 INB INC 2 3 14 OUTA 13 OUTB 12 OUTC
Applications Information
Input Considerations
Use 0.1F 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.
IND 4 DISABLE 5 GND 6 GND 7
MAX7448
11 OUTD 10 VCC 9 8 GND GND
TSSOP
Output Considerations
The outputs are typically connected to a 75 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 220F.
Chip Information
TRANSISTOR COUNT: 6300 PROCESS: BiCMOS
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4-Channel RGB Video Filter with Asynchronous CVBS Input
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.)
MAX7448
PACKAGE OUTLINE, TSSOP, 4.40 MM BODY EXPOSED PAD
21-0108
C
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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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
TSSOP 4.4mm BODY.EPS

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