KA22712B dolby b-type nr processor introduction the KA22712B is a monolithic intergrated circuit designed for use in dolby*b-type noise reduction systems. features few external components low quiescent circuit current (typ i ccq = 5.3ma) high crosstalk rejection ratio built in nr-swich, rec/pb-switch recommended supply voltage : v cc = 6.5v ~ 16v block diagram *; ? dolby ? and double-d symbol are trademarks of dolby laboratories licensing corporation. this i.c is availavle only to licensees of dolby laboratories licensing corporation, san francisco, from whom licensing and applicationinformation must be obtained. voltage regulator control swtch 10 12 13 4 7 9 11 buffer vca & hpf rms detector gain factor rms detector vca & hpf 8 6 buffer 2 5 15 3 1 14 16 rec in2 pb in2 pb out2 rec out2 v cc ripple filter nr sw r/r sw gnd rec in1 pb in1 pb out1 rec out1 fig. 1 ordering information device package operating temperature KA22712B 16-dip-300a -30 c ~ +85 c KA22712Bd 16-sop-225a 16-sop-225a 16-dip-300a ripple filter r-constabt ripple filter
KA22712B dolby b-type nr processor pin configuration absolute maximum ratings (ta = 25 c ) characteristic symbol value unit supply voltage v cc 16 v power dissipation p d 750 mw operating temperature t opr -30 ~ +85 c storage temperature t stg -40 ~ +125 c note : derated above ta = 25 c in the propation of 10mw/ c electrical characteristics (ta = 25 c , vcc = 9v, f = 1khz, 0db = 245mw (-10dbm) at rec out, unless otherwise specified) characteristic symbol test condition min typ max unit quiescent citcuit current i ccq rec mode, nr-off, v i = 0 4.5 5.3 7 ma buffer voltage gain g v rec mode, pb out = 0db 22 24 26 db 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 ka2271b fig. 2 rec output1 ripple filter pb output1 rec/pb control r-constant pb input1 gnd rec input1 rec output2 ripple filter pb output2 nr control input ripple filter pb input2 v cc rec input2 ka00712b
KA22712B dolby b-type nr processor recout = -25db, f = 500hz 1.4 2.9 4.4 db recout = -25db, f = 2khz 5.4 7.0 8.5 db nr-rec boost g v(bst) recout = -25db, f = 5khz 3.9 5.4 6.9 db recout = -40db, f = 10khz 9.1 10.4 11.9 db recout = 0db, f = 10khz -1.1 0.4 1.9 db nr-boost balance cb nr-rec boost ch to ratio 0 1 db max.recout level v o (max) rec mode, nr-off thd = 1% 14 16 db rec output voltage thd rec mode, nr-off recout = 10db 0.04 0.1 % rec mode, nr-on recout = 10db 0.04 0.1 % nr-effect s/n s/n rec mode, r g = 2.2k filter = ccir/arm 65 69 db crosstalk ct nr-off output = 0db pb to rec -70 -65 db ch to ch, nr-off output = 0db -70 -65 db input impedance z i 30 47 65 k w switch control v ctl high mode 2.4 v voltage low mode 0 0.4 v input level rec v i rec mode, nr-off recout = 0db 19.5 24.5 31.0 mv pb v i pb mode, nr-off recout = 0db 19.5 24.5 31.0 mv output level v o rec mode, nr-off recout = 0db testpoint = pb output
KA22712B dolby b-type nr processor application information 1) power supply the KA22712B can be operated at 6.5v ~ 16v in case of signale and 3.25v - 8v in dual power supply. 2) switch control voltage all function of KA22712B are controlled by internal electronic switchs. the function switch is operated by d.c. voltage of nr and r.p control pins. nr, r/p v h v l condition pb rec nr-off nr-on single dual power 2.4v ?a v h 0.4v ?? v l v h ? 3 v ee + 2.4v v ee + 0.4v 3 v l 3) reference level the reference output level of dolby noise reduction system is defined as dolby level. the dolby level of KA22712B is 245mv (-10dbm) at f = 400hz.100 5 6 7 8 12 11 10 9 dual power connection ka2271b fig. 4 KA22712B +v bb gnd -v ee
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