Triple-Channel Video Reconstruction Filter and Buffer for Composite and Y/C Outputs

Transcription

1 9-3269; Rev ; 6/5 EVALUATION KIT AVAILABLE Triple-Channel Video Reconstruction Filter and General escription The is a low-cost, triple-channel video reconstruction filter for S-video and CVBS video-signal applications. This device is ideal for anti-aliasing and AC smoothing video applications such as set-top boxes, V players, hard-disk recorders (HRs), and personal video recorders. This filter operates from a single +5V supply. It is optimized for NTSC, PAL, and standard-definition TV (STV) video systems. Each channel consists of a lowpass filter and an output buffer capable of driving one (, COUT) or two (CVOUT) standard 5Ω video loads. The output buffers can drive either an AC or a C load such that the blanking level voltage after the backmatch resistor is less than V. The Y and C video inputs are summed to produce the composite video output. The has a maximally flat frequency response. The is available in an 8-pin SO package and is fully specified over the commercial ( C to +7 C) temperature range. Applications Set-Top Boxes/HRs/Vs Security Cameras/igital Cameras Game Consoles igital VCRs Every Composite, S-Video Output for NTSC, PAL, and STV Features Triple-Channel Filter and Buffer for CVBS and Y/C (S-Video) Video Signals Filter Response Ideal for NTSC, PAL, and Interlaced STV Signals 42dB (typ) Stopband Attenuation at 27MHz -.3dB (typ) Passband Response <V Blanking Level Allows C-Coupled Output CVOUT rives Two 5Ω Video Loads and COUT rive One 5Ω Video Load +5V Single-Supply Voltage 8-Pin SO Package Ordering Information PART TEMP RANGE PIN-PACKAGE CSA C to +7 C 8 SO TOP VIEW N.C. GN CIN Pin Configuration V CC CVOUT COUT SO Functional iagram ENCOER V CC /A LOWPASS FILTER Σ CVOUT /A CIN LOWPASS FILTER COUT GN Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/allas irect! at , or visit Maxim s website at

2 ABSOLUTE MAXIMUM RATINGS V CC to GN...+6V All Other Pins to GN...-.3V to (V CC +.3V) Maximum Current into Any Pin Except V CC and GN...±5mA Continuous Power issipation (T A = +7 C) 8-Pin SO mW Operating Temperature Range... C to +7 C Storage Temperature Range C to +5 C Junction Temperature...+5 C Lead Temperature (soldering, s)...+3 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 = to 2pF, all loads to GN for C-couple, all loads to V CC / 2 for AC-couple, C = C CIN =.µf, R = 5Ω, R COUT = 5Ω, R CVOUT = 75Ω, T A = T MIN to T MAX, unless otherwise noted. Typical values are at T A = +25 C.) PARAMETER SYMBOL CONITIONS MIN TYP MAX UNITS Passband Response f = khz to 4.2MHz, relative to khz db Stopband Attenuation A SB f = 27MHz db Chroma/Luma Gain f = 3.58MHz, reference to CVOUT at 336kHz % ifferential Gain dg 5-step modulated staircase.5.5 % ifferential Phase dθ 5-step modulated staircase.5.5 egrees Signal-to-Noise Ratio SNR Peak signal (2V P-P ) to RMS noise, f = Hz to 5MHz db Line-Time istortion H IST 8µs, IRE bar.3 % Field-Time istortion V IST 3 lines, 8µs, IRE bar.5 % Clamp Settling Time To ±% 3 Lines Output C Clamp Level CVOUT COUT Low-Frequency Gain Accuracy A V f = khz, relative to 6dB % Group-elay eviation Δt g eviation from khz to 4.MHz 8 6 ns Group-elay Matching tg(match) Low-frequency channel-to-channel matching, f = khz for and COUT V 2 ns Channel-to-Channel Crosstalk X TALK f = khz to 3.58MHz 6 db Input Leakage Current I IN µa Input ynamic Swing SUPPLY Y INP-P.2 C INP-P.9 Supply Voltage Range V CC V Supply Current I CC V CC = +5.25V, no load ma Power-Supply Rejection Ratio PSRR V IN = mv P-P, f = to 3.5MHz 33 db V P-P 2

3 (V CC = +5V, T A = +25 C, unless otherwise noted.) AMPLITUE (db) AMPLITUE vs. FREQUENCY toc AMPLITUE (db) Typical Operating Characteristics PASSBAN AMPLITUE vs. FREQUENCY PHASE RESPONSE vs. FREQUENCY NORMALIZE TO db NORMALIZE TO db toc2 PHASE (EGREES) toc GROUP ELAY vs. FREQUENCY toc4 2T RESPONSE (IRE = 7.4mV) toc5 MOULATE 2.5T RESPONSE (IRE = 7.4mV) toc6 MEASURE AT TERMINATION GROUP ELAY (ns) MEASURE AT TERMINATION 2mV/div 2mV/div 5mV/div 5mV/div 4. ns/div 4ns/div SUPPLY CURRENT (ma) SUPPLY CURRENT vs. TEMPERATURE TEMPERATURE ( C) toc7 IFFERENTIAL PHASE (EGREES) IFFERENTIAL GAIN (%) IFFERENTIAL GAIN st 2nd 3rd 4th 5th 6th IFFERENTIAL PHASE st 2nd 3rd 4th 5th 6th toc8 MULTIBURST RESPONSE μs/div toc9 MEASURE AT TERMINATION 5mV/div 5mV/div 3

4 PIN NAME FUNCTION Luma (Y) Input 2 N.C. No Connection. No internal connection. 3 GN Ground 4 CIN Chroma (C) Input 5 COUT Chroma (C) Output 6 CVOUT Composite Video Output 7 V CC 5V Power Supply 8 Luma (Y) Output Pin escription etailed escription The primary function of the is to filter and buffer the encoder AC outputs that contain digital video information in applications such as set-top boxes, HRs, V players, and digital VCRs. This device reconstructs and cleans up analog video signals. The consists of a lowpass filter and a -gain output video buffer. The luma () and chroma (CIN) video inputs are summed internally to provide the composite (CVOUT) video output. These devices operate from a single +5V supply. The filters have a nominal cutoff frequency optimized for NTSC, PAL, and STV. 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 42dB (typ) of attenuation at sampling frequencies of 27MHz and above (see the Typical Operating Characteristics). Output Buffer The and COUT buffers have a fixed gain capable of driving one standard 5Ω video load with a 2V P-P signal. The CVOUT buffer has a fixed gain, capable of driving two 5Ω video loads. The 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 C load with an output blanking level of less than V. Output Clamp Level When sync pulses in the luma signal (Y) are detected, the C restore loop is activated. The function of the loop is to set the sync tip of the video signal to the desired C level of.8v for and COUT, and to set the average C voltage of COUT at.6v. Applications Information Input Considerations Use a.µf ceramic capacitor to AC-couple the input to the. This input capacitor stores a C level such that the outputs are clamped to the appropriate C voltage level. Output Considerations The outputs of the 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 blanking level of the video cable is always less than V, 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 22µF. Power-Supply Bypassing and Layout The operates from a single +5V supply. Bypass V CC to GN with a.µf 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. Chip Information TRANSISTOR COUNT: 4 PROCESS: BiCMOS 4

5 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 N E H INCHES MILLIMETERS IM A MIN.53 MAX.69 MIN.35 MAX.75 A B C e.5 BSC.27 BSC E H L SOICN.EPS TOP VIEW VARIATIONS: IM INCHES MILLIMETERS MIN MAX MIN MAX N MS AA AB AC A C e B A FRONT VIEW L SIE VIEW -8 PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE,.5" SOIC APPROVAL OCUMENT CONTROL NO. REV. 2-4 B 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, 2 San Gabriel rive, Sunnyvale, CA Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.