KA2271B dolby b-type nr processor introduction the KA2271B 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 = 8v ~ 16v block diagram *; ? dolby ? and double-d symbol are trademarks of dolby laboratories licensing corporation. this i.c is available only to licensees of dolby laboratories licensing corporation, san francisco, from whom licensing and application information must be obtained. 11 9 5 2 4 7 8 9 3 1 14 16 15 10 12 13 vca & hpf rms detector gain factor rms detector vca & hpf buffer buffer voltage regulator control switch rec in2 pb in2 pb out2 rec out2 pipple filter r-constant ripple filter rec out1 pb out1 pb in1 rec in1 gnd r/p sw nr sw r/r vcc ordering information device package operating temperature KA2271B 16-dip-300a KA2271Bd 16-sop-225a 16-sop-225a 16-dip-300a -30 c ~ +85 c fig. 1
KA2271B 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 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
KA2271B dolby b-type nr processor electrical characteristics (ta = 25 c, vcc = 12v, 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 3.5 5.6 7 ma buffer voltage gain g v rec mode, pb out = 0db 25 27 29 db recout = -25db, f = 500hz 1.4 2.9 4.4 db recout = -25db, f = 2khz 5.5 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 9.0 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 15.9 db rec output voltage thd rec mode, nr-off recout = 10db 0.04 0.2 % rec mode, nr-on recout = 10db 0.04 0.3 % 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 -60 db ch to ch, nr-off output = 0db -70 -60 db input impedance z i 30 47 60 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 -32 -30 -28 dbm pb v i pb mode, nr-off recout = 0db -32 -30 -28 dbm output level v o rec mode, nr-off recout = 0db testpoint = pb output 489 549 616 m v
KA2271B dolby b-type nr processor 1 2 3 4 5 6 7 8 13 14 15 16 KA2271B 9 10 11 12 rec output2 pb output2 pb input2 rec input2 vcc rec output1 pb output1 pb input1 rec 100k 100k 2.2k 2.2k 1u 1u 1u 1u 100u 0.68u (10%) nr on off 15k 4.7k r/p pb rec 100k 100k 2.2k 2.2k 1u 1u 1uf 1u 0.68u (10%) 47k input1 (2%) test circuit fig. 3
KA2271B dolby b-type nr processor application information 1) power supply the KA2271B can be operated at 8v ~ 16v in case of single and 4v ~ 8v in dual power supply. 2) switch control voltage all function of KA2271B 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 3 v h 0.4v 3 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 KA2271B is 245mv (-10dbm) at f = 400hz. 5 6 7 8 12 11 10 9 dual power connection KA2271B fig. 4 gnd +v bb -v ee
|
