19-2948; Rev 0; 8/03 4-Channel Video Reconstruction Filter Features ♦ 4-Channel Filter and Buffer for CVBS, RGB, or Y/C Video Signals The MAX7445 has three modes of operation. Mode 1 processes CVBS and RGB video signals. Mode 2 processes CVBS, Y, and C signals, as well as a second asynchronous CVBS video signal. Mode 3 processes RGB and CVBS (asynchronous) video signals. An external pin adjusts the gain of the video buffer to either +6dB, +9.5dB, or +12dB to accommodate video-encoder DAC output signals of <1V. High-frequency boost circuitry 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. ♦ Filter Response Ideal for NTSC, PAL, and Interlaced SDTV Video Signals ♦ 43dB (typ) Stopband Attenuation at 27MHz ♦ ±0.75dB (max) Passband Ripple Out to 5MHz ♦ Blanking Level Voltage on Cable <1V ♦ Each Channel Drives Two 150Ω Video Loads ♦ +5V Single-Supply Voltage ♦ Selectable Gain: +6dB, +9.5dB, and +12dB ♦ Small 14-Pin TSSOP Package Ordering Information PART TEMP RANGE PIN-PACKAGE MAX7445EUD -40°C to +85°C 14 TSSOP-EP* *EP = Exposed pad. The MAX7445 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 DVD Players Digital VCRs Pin Configuration appears at end of data sheet. Desktop Video Editors Functional Diagram VCC ENCODER 75Ω 0.1µF D/A 75Ω * INA LOWPASS FILTER OUTA SYNC DETECTOR 75Ω * 75Ω 0.1µF D/A 75Ω * INB LOWPASS FILTER OUTB LOWPASS FILTER OUTC 75Ω 75Ω 0.1µF INC D/A 75Ω 75Ω * * * 75Ω 75Ω 75Ω SELECT MAX7445 75Ω 0.1µF D/A IND LOWPASS FILTER OUTD SYNC DETECTOR 75Ω * * 75Ω 75Ω *OPTIONAL CAPACITORS GND DISABLE GAIN ________________________________________________________________ Maxim Integrated Products 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. 1 MAX7445 General Description The MAX7445 4-channel, buffered video reconstruction filter is ideal for anti-aliasing and 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 standard-definition digital TV (SDTV) video systems. Each output is capable of driving two standard 150Ω video loads. MAX7445 4-Channel Video Reconstruction Filter 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 = +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 (VCC = +5V ±5%, CL = 0 to 20pF, RL = 75Ω to GND for DC-coupled load, RL = 75Ω to VCC / 2 for AC-coupled load, CIN_ = 0.1µF, GAIN = GND (+6dB) or VCC (+9.5dB), TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS f = 100kHz to 5MHz, relative to 100kHz Passband Response Stopband Attenuation ASB f ≥ 27MHz Differential Gain dG 5-step modulated staircase Differential Phase Signal-to-Noise Ratio Group Delay Deviation dθ 5-step modulated staircase SNR Peak signal (2VP-P) to RMS noise, f = 100Hz to 50MHz ∆tg Deviation from 100kHz to 4.1MHz MIN TYP MAX Channel without boost (see Table 2) -0.75 +0.15 +0.75 Channel with boost (see Table 2) +0.9 +1.2 +1.5 39 43 UNITS dB dB Gain = +6dB, +9.5dB 0.15 0.50 Gain = +12dB 0.25 0.90 Gain = +6dB, +9.5dB 0.15 0.50 Gain = +12dB 0.15 0.60 Gain = +6dB, +9.5dB, +12dB 69 Channel without boost (see Table 2) 75 11 % Degrees dB 20 ns Channel with boost (see Table 2) 17 30 Line-Time Distortion HDIST 18µs, 100 IRE bar 0.3 Field-Time Distortion VDIST 130 lines, 18µs, 100 IRE bar 0.5 % Clamp Settling Time tCLAMP To ±1% 100 Lines SELECT = GND Output DC Clamp Level SELECT = VCC SELECT = floating Low-Frequency Gain Accuracy AV Low-Frequency Gain Matching AV(MATCH) 2 Channel A 0.6 0.9 1.1 Channels B, C, D 1.1 1.5 1.8 Channels A, B, D 0.6 0.9 1.1 Channel C 1.25 1.6 1.95 Channels A, D 0.6 0.9 1.1 Channels B, C 1.1 1.5 1.8 f = 100kHz, relative to a gain of +6dB -3 Low-frequency channel-to-channel matching, f = 100kHz _______________________________________________________________________________________ % V +3 % 4 % 4-Channel Video Reconstruction Filter (VCC = +5V ±5%, CL = 0 to 20pF, RL = 75Ω to GND for DC-coupled load, RL = 75Ω to VCC / 2 for AC-coupled load, CIN_ = 0.1µF, GAIN = GND (+6dB) or VCC (+9.5dB), TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V, TA = +25°C.) PARAMETER Group Delay Matching Channel-to-Channel Crosstalk SYMBOL CONDITIONS tg(MATCH) Low-frequency channel-to-channel matching, f = 100kHz 2 ns f = 100kHz to 3.58MHz 60 dB OUT_ shorted to GND or VCC 70 XTALK Output Short-Circuit Current ISC Input Leakage Current IIN TYP MAX SELECT = VCC SELECT = floating Channel A UNITS mA 10 SELECT = GND Input Dynamic Swing for Gain of +6dB MIN µA 1.2 Channels B, C, D 0.9 Channels A, B, D 1.2 Channel C 0.9 Channels A, D 1.2 Channels B, C 0.9 VP-P SUPPLY Supply Voltage Range VCC Supply Current ICC Power-Supply Rejection Ratio PSRR 4.75 5.25 V 140 mA No load 100 VIN = 100mVP-P, f = 0 to 3.5MHz 40 dB At 5MHz 2 kΩ DISABLE Output Impedance During Disable Disable Logic-Input High Voltage Disable Logic-Input Low Voltage Disable Logic Input Current ZDISABLE VIH 2.0 VIL IDISABLE VIL = 0V (sink), VIH = VCC (source) V 0.8 V ±10 µA _______________________________________________________________________________________ 3 MAX7445 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = +5V, VGAIN = 0V, TA = +25°C, unless otherwise noted.) PASSBAND AMPLITUDE vs. FREQUENCY 0 1.5 PHASE RESPONSE vs. FREQUENCY 200 MAX7445 toc02 MAX7445 toc01 2.0 HIGH-FREQUENCY BOOST 150 100 -40 PHASE (DEGREES) AMPLITUDE (dB) AMPLITUDE (dB) 1.0 -20 0.5 0 -0.5 FLAT PASSBAND RESPONSE -1.5 NORMALIZED TO 0dB -150 -200 -2.0 10 100 0.1 1 0.1 10 FREQUENCY (MHz) FREQUENCY (MHz) GROUP DELAY vs. FREQUENCY 2T RESPONSE (1 IRE = 7.14mV) MAX7445 toc04 90 80 10 1 FREQUENCY (MHz) MODULATED 12.5T RESPONSE (1 IRE = 7.14mV) MAX7445 toc06 MAX7445 toc05 100 GROUP DELAY (ns) 0 -50 NORMALIZED TO 0dB -80 1 50 -100 -1.0 -60 MAX7445 toc03 AMPLITUDE vs. FREQUENCY IN_ IN_ 250mV/ div 250mV/ div OUT_ OUT_ 250mV/ div 250mV/ div 70 60 50 0.1 200ns/div 400ns/div DIFFERENTIAL GAIN MULTIBURST RESPONSE 10 1 FREQUENCY (MHz) 110 100 90 80 -40 -15 10 35 TEMPERATURE (°C) 4 60 85 MAX7445 toc09 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 MAX7445 toc08 MAX7445 toc07 INPUTS BIASED TO +2V NO LOAD DIFFERENTIAL PHASE (DEGREES) DIFFERENTIAL GAIN (%) SUPPLY CURRENT vs. TEMPERATURE 120 SUPPLY CURRENT (mA) MAX7445 4-Channel Video Reconstruction Filter 1st 2nd 3rd 4th 5th 6th IN_ 250mV/ div DIFFERENTIAL PHASE 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 OUT_ 250mV/ div 1st 2nd 3rd 4th 5th 6th 10µs/div _______________________________________________________________________________________ 4-Channel Video Reconstruction Filter PIN NAME 1 INA Channel A Video Input. AC-couple INA with a series 0.1µF capacitor. 2 INB Channel B Video Input. AC-couple INB with a series 0.1µF capacitor. 3 INC Channel C Video Input. AC-couple INC with a series 0.1µF capacitor. 4 IND Channel D Video Input. AC-couple IND with a series 0.1µF capacitor. 5 6, 8 FUNCTION Disable Logic Input. A logic-low on DISABLE enables the output buffers. A logic-high on DISABLE disables DISABLE all output buffers and puts them in a high-impedance state. GND Ground 7 GAIN Gain-Control Input. Connect GAIN to GND for a gain of +6dB (+2V/V), to VCC for a gain of +9.5dB (+3V/V), or leave unconnected for a gain of +12dB (+4V/V). 9 SELECT 10 VCC 11 OUTD 12 OUTC Channel C Video Output. This output can be either AC- or DC-coupled. 13 OUTB Channel B Video Output. This output can be either AC- or DC-coupled. 14 OUTA Channel A Video Output. This output can be either AC- or DC-coupled. Mode Select Input. Connect to GND for CVBS/RGB processing, to VCC for CVBS/Y/C/CVBSASYNC processing, or leave floating for RGB/CVBSASYNC (G with sync) processing. +5V Supply Input Channel D Video Output. This output can be either AC- or DC-coupled. Detailed Description The MAX7445 filters and buffers video-encoder DAC outputs in applications such as set-top boxes, harddisk recorders, DVD players, and digital VCRs. The MAX7445 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 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. The MAX7445 has three modes of operation allowing different video signals to be processed. The modes are shown in Table 1. Mode 1 requires that channel A is a video signal that includes a sync pulse. A sync separator uses this signal to extract the timing required to clamp all four channels. Modes 2 and 3 require that channel A and channel D have a sync pulse to provide the required timing information. Channel A provides the required timing for channels A, B, and C while channel D provides its own sync separator to extract the sync signal from an asynchronous video signal. Table 1. Operating Modes MODE MODE 1 CVBS/RGB MODE 2 CVBS/Y/C/ CVBSASYNC SELECT GND VCC MODE 3 RGB/CVBSASYNC FLOATING (G with sync) CHANNEL SIGNAL A CVBS B R C G D B A CVBS B Y C C D CVBSASYNC A G (with sync) B R C B D CVBSASYNC 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). _______________________________________________________________________________________ 5 MAX7445 Pin Description MAX7445 4-Channel Video Reconstruction Filter 12dB Gain Setting GAIN is biased internally to V CC / 2 with a resistordivider pair of 100kΩ resistors from VCC to GND such that the internal impedance at the node is 50kΩ. No additional connection is necessary since the input offers a minimum noise-margin immunity of 1VP-P. Table 2. High-Frequency Boost for Each Mode CHANNEL HIGH-FREQUENCY BOOST (dB) MODE 1 MODE 2 MODE 3 A +1.2 +1.2 – B – +1.2 – C – +1.2 – D – +1.2 +1.2 Output Clamp Level When sync pulses are detected in either a CVBS or G video signal, the DC restore loop is activated. The function of the loop is to set the DC level of the video signal to a specified voltage. See Table 4 for clamp levels. Table 3. Gain Setting Control Applications Information GAIN BUFFER GAIN (dB) GND +6 VCC +9.5 Floating +12 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. High-Frequency Boost The high-frequency boost available on the CVBS, Y, and C video channels increases image sharpness by compensating for signal degradation and roll-off in the video encoder. Table 2 shows the channels that have the highfrequency boost option for the three operating modes. The channels without high-frequency boost have a flat response over the video bandwidth. Output Buffers Each output buffer can drive two 150Ω video loads with a 2VP-P signal. The output buffer gain is selectable between +6dB, +9.5dB, or +12dB by using GAIN (see Table 3). The MAX7445 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 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 MAX7445 operates from a single +5V supply. Bypass VCC to GND with a 0.1µF capacitor. Place all external components as close to the device as possible. Table 4. Output Clamp Level CHANNEL 6 MODE 1: SELECT = GND MODE 2: SELECT = VCC MODE 3: SELECT = FLOATING CLAMP LEVEL (V) SYNC SOURCE CLAMP LEVEL (V) SYNC SOURCE CLAMP LEVEL (V) SYNC SOURCE A 0.8 Channel A 0.8 Channel A 0.8 Channel A B 1.4 Channel A 0.8 Channel A 1.4 Channel A C 1.4 Channel A 1.6 Channel A 1.4 Channel A D 1.4 Channel A 0.8 Channel D 0.8 Channel D _______________________________________________________________________________________ 4-Channel Video Reconstruction Filter TOP VIEW INA 1 14 OUTA INB 2 13 OUTB INC 3 12 OUTC IND 4 MAX7445 11 OUTD 10 VCC DISABLE 5 GND 6 9 SELECT GAIN 7 8 GND 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. Chip Information TRANSISTOR COUNT: 6300 PROCESS: BiCMOS TSSOP _______________________________________________________________________________________ 7 MAX7445 Pin Configuration 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 MAX7445 4-Channel Video Reconstruction Filter 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. 8 _____________________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.