general description the max7447 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/ter- restrial 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 150 ? video loads. the max7447 processes s-video and cvbs video sig- nals. the video output buffers have a fixed gain of +6db. each channel has high-frequency boost circuitry that pro- vides picture sharpness with up to +1.2db of gain boost without degradation in the stopband. the output video drivers can be disabled with an external pin. the max7447 is available in a 14-pin tssop package with an exposed pad, and is specified over the -40? to +85? extended temperature range. applications set-top boxes/hdrs dvd players game consoles digital vcrs desktop video editors features ? 4-channel filter and buffer for s-video and cvbs signals ? 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 output <1v ? each channel drives two 150 ? video loads ? +5v single-supply voltage ? small 14-pin tssop package max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input ________________________________________________________________ maxim integrated products 1 disable v cc gnd max7447 outa * * outb * * outc * * outd * * 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? 75 ? *optional capacitors ina 0.1 f 0.1 f 0.1 f 0.1 f inb inc ind d/a encoder cvbs cvbs y c d/a d/a d/a sync detector lowpass filter lowpass filter lowpass filter lowpass filter sync detector functional diagram ordering information 19-2950; rev 1; 4/06 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. * ep = exposed pad. pin configuration appears at end of data sheet. part temp range pin- package package code max7447eud -40? to +85? 14 tssop-ep* u14e-3
max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v cc = +5v ?%, c l = 0 to 20pf, r l = 75 ? to gnd for dc-coupled load, r l = 75 ? to v cc / 2 for ac-coupled load, c in_ = 0.1?, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, t a = +25?.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. 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 .....?0ma continuous power dissipation (t a = +70?) tssop-ep (derate 20.8mw/? above +70?) ...........1667mw operating temperature range ...........................-40? to +85? storage temperature range .............................-65? to +150? junction temperature ......................................................+150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units passband response f = 100khz to 5mhz, relative to 100khz 0.9 1.2 1.5 db stopband attenuation a sb f 27mhz 39 43 db differential gain dg 5-step modulated staircase 0.15 0.50 % differential phase d 5-step modulated staircase 0.15 0.50 d eg r ees signal-to-noise ratio snr peak signal (2v p-p ) to rms noise, f = 100hz to 50mhz 80 db group delay deviation ? t g deviation from 100khz to 4.1mhz 17 30 ns line-time distortion h dist 18?, 100 ire bar 0.3 % field-time distortion v dist 130 lines, 18?, 100 ire bar 0.5 % clamp settling time t clamp to ?% 430 lines channel a, b, d 0.6 0.9 1.1 output dc clamp level channel c 1.25 1.60 1.95 v low-frequency gain accuracy a v f = 100khz, relative to a gain of +6db -3 +3 % low-frequency gain matching a v ( m atc h ) low-frequency channel-to-channel matching, f = 100khz 4% group delay matching t g(match) low-frequency channel-to-channel matching, f = 100khz 2ns channel-to-channel crosstalk x talk f = 100khz to 3.58mhz 60 db output short-circuit current i sc out_ shorted to gnd or v cc 70 ma input leakage current i in 10 ? channel a, b, d 1.2 input dynamic swing channel c 0.9 v p-p supply supply voltage range v cc 4.75 5.25 v supply current i cc no load 100 140 ma power-supply rejection ratio psrr v in = 100mv p-p , f = 0 to 3.5mhz 40 db
max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input _______________________________________________________________________________________ 3 amplitude vs. frequency max7447 toc01 frequency (mhz) amplitude (db) 10 -80 -60 -40 -20 0 1100 normalized to 0db passband amplitude vs. frequency max7447 toc02 frequency (mhz) amplitude (db) 1 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 -2.0 0.1 10 normalized to 0db high-frequency boost phase response vs. frequency max7447 toc03 frequency (mhz) phase (degrees) 1 -150 -100 -50 0 50 100 150 200 -200 0.1 10 group delay vs. frequency max7447 toc04 frequency (mhz) group delay (ns) 1 60 70 80 90 100 50 0.1 10 2t response (1 ire = 7.14mv) max7447 toc05 200ns/div 250mv/div 250mv/div out- in- modulated 12.5t response (1 ire = 7.14mv) max7447 toc06 400ns/div 250mv/div 250mv/div in- out- t ypical operating characteristics (v cc = +5v, t a = +25?, unless otherwise noted.) electrical characteristics (continued) (v cc = +5v ?%, c l = 0 to 20pf, r l = 75 ? to gnd for dc-coupled load, r l = 75 ? to v cc / 2 for ac-coupled load, c in_ = 0.1?, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, t a = +25?.) parameter symbol conditions min typ max units disable outp ut im p ed ance d ur i ng d i sab l e z disable at 5mhz 2 k ?
max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input 4 _______________________________________________________________________________________ pin description detailed description the max7447 filters and buffers video-encoder dac outputs in applications such as set-top boxes, hard- disk recorders, dvd players, and digital vcrs. the max7447 reconstructs and cleans up analog video sig- nals from the output of dac video encoders. each channel consists of a lowpass filter and an output video buffer that drives two standard 150 ? video loads. the max7447 is designed to process s-video and cvbs video signals. the video signal processed by channel a (cvbs video signal) must include a sync pulse. this sync pulse provides the required timing for channels a, b, and c. channel d allows an asynchro- nous cvbs 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. supply current vs. temperature max7447 toc07 temperature ( c) supply current (ma) 60 35 10 -15 90 100 110 120 80 -40 85 inputs biased to +2v no load differential gain max7447 toc08 differential phase (degrees) 1st 3rd 2nd 4th 5th 6th 1st 3rd 2nd 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 multiburst response max7447 toc09 10 s/div 250mv/div 250mv/div t ypical operating characteristics (continued) (v cc = +5v, t a = +25?, unless otherwise noted.) pin name function 1 ina c hannel a v i d eo inp ut. u se ch annel a for a c v bs video signal. ac - c oup l e in a w i th a ser i es 0.1 f cap aci tor . 2 inb channel b video input. use channel b for the luma (y) video signal. ac-couple inb with a series 0.1? capacitor. 3 inc channel c video input. use channel c for the chroma (c) video signal. ac-couple inc with a series 0.1? capacitor. 4 ind channel d video input. use channel d for a second cvbs video signal. ac-couple ind with a series 0.1? capacitor. 5 disable disable logic input. a logic-low on disable enables the output buffers. a logic-high on disable disables all output buffers and puts them in a high-impedance state. 6? gnd ground 10 v cc +5v supply input 11 outd channel d video output. this output can be either ac- or dc-coupled. 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.
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 video-encoder dac sampling frequency of 27mhz and above (see the typical operating characteristics ). high-frequency boost each channel has a +1.2db high-frequency boost that increases image sharpness by compensating for signal degradation and rolloff in the video encoder. output buffers each output buffer has a fixed gain of +6db and can drive two 150 ? video loads with a 2v p-p signal. the max7447 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. output clamp level when a sync pulse is detected on channel a (cvbs), the dc restore loop is activated for channels a, b, and c. channel d? 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 a specified voltage. see table 1 for clamp levels and sync source. applications information input considerations use 0.1? 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. 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 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 220?. power-supply bypassing and layout the max7447 operates from a single +5v supply. bypass v cc to gnd with a 0.1 f 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 connect- ed to gnd and should be connected to the ground plane for improved thermal conductivity. do not route signals under this package. max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input _______________________________________________________________________________________ 5 14 13 12 11 10 9 8 1 2 3 4 5 6 7 outa outb outc outd ind inc inb ina top view max7447 v cc gnd gnd gnd gnd disable tssop pin configuration chip information transistor count: 6300 process: bicmos table 1. output clamp level and sync source channel clamp level (v) sync source (v) a 0.8 channel a b 0.8 channel a c 1.6 channel a d 0.8 channel d
max7447 4-channel s-video, cvbs video filter with asynchronous cvbs input maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it 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 2006 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .) tssop 4.4mm body.eps e 1 1 21-0108 package outline, tssop, 4.40 mm body, exposed pad xx xx
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