ADT2450 5v operating ir receiver with excellent noise performance for r/c feb. 05. 2005 / rev. 0.0 http://www.ad-tech.co.kr 1/4 ADT2450 is a m i nia t urized r e c e ive r ic for us e in the infrare d re mote control syste m . it has 5v voltage oper a ting, a high sens itivity, and good noise i m munit y to a power and ext e rnal light. this can a l so be suitable for high optic al and el ectri c a l disturbances and good for a n 5v appli cat ion system. it has the frequency selecting pads f o r setting the center f r equency of band-pass f ilter and also has 5 tri m ming pa ds for the fi ned adjust of c e nt er frequency. this ic is capabl e of a c c e pti ng a photodiode di rectly and i n clude many exc e ll ent c i rcuit such as an interna l vol tage r e ference for bet t er te mperature c hara ct eristics, a high ga in initi al a m pli f i e r, a gain contr o l a m pl ifier, a li mi ter, a band pass fil t er, a det e ct i on circui t, two comparator c i rcui ts, gain control circuits, integra t or ci rcuits, a wavefor m shapi ng circui t assem b led on a single chip. this ic also has a powerful noise suppression to any kinds of externa l l i ght. general d e s c r iption features ? 5v operating ? i nternal vol tage r e ference and curre nt reference circui t for bett er temper ature char acteristics ? m axi m um i n terference safety against optical and ele c tri c a l disturbances ? n o externa l components nec e ssary ? t he center frequency c a n be varied with option pad s ( 32.7khz, 36.7khz, 37.9khz, 40khz, 56.7khz ) ? in ternal filter for a high frequency lighting flu o rescent lamp w i th a g c control (powerful noise cancel) ? o pen coll e c t or output (open coll e c t o r output with a pull-up resistor) ? o utput ac ti ve low abso lute m aximum ratings parameter s ymbol m in. supply voltage vcc 0 6.0 v output volt age vout 0 6.0 v output current iout 0 2.5 ma operating te mper ature t opr -20 8 0 ? -40 tst max. unit storage temperatur e 125 ? * st ress ab ove t h o s e l i s t e d un der abs o l u t e m a xi m u m r a t i ng s m a y cause per m anent dam a g e of devi ce. t h i s i s st ress rat i ng on l y and fu nct i o nal o p e r a t i on of t h e d e vi ce at t h ese or any ot her condi t i o n s abo v e t h o s e i n dicat ed in t h e o p e ratio n a l se ctio n s o f this sp ecifi c a tio n i s no t im p lied . ex po su re to abso l u te max i m u m r a tin g co nd iti on s for lon g e r p e rio d s m a y a f f e ct d e v i ce r e li ab ility. d u rin g o v erload con d iti on s (vin>vcc or vin ADT2450 5v operating ir receiver with excellent noise performance for r/c feb. 05. 2005 / rev. 0.0 http://www.ad-tech.co.kr 2/4 recommen d ed o p erating co n d iti o ns parameter s ymbol m in. operating voltage vcc 4.5 5.0 5.5 v input frequency f in 30 38 60 khz -20 top typ. max. unit operating temper ature 2 5 8 0 ? f u n ctio nal block diagram in pre amp i-v converter & input bias control agc amp lim i t amp band-pass filter frequency setting frequency t r i mmi ng f s et bias c i rcui t noise det. & gain ctrl w ith gap d e t. com p arator threshold control circuit integrator & wave sha p ing output sta g e trimming pads(t1~t 5 ) fr eq.sele c tion op t i on pads (s 1~ s4) * fc( cent e r frequency) c a n be varied with 4 option pads : 32.7khz , 36.7khz, 37.9khz, 40.0khz, 56.7khz gnd vcc voltage & curr e n t reference circuit out fc(center frequency) pad settin g method (s1,s2,s3,s4) 32.7 khz s4(p ad10) is ground 36.7 khz s3(p ad11) is ground 37.9 khz s2(p ad12) is ground 40.0 khz 56.7 khz s1(p ad13) is ground no connec t i o n
ADT2450 5v operating ir receiver with excellent noise performance for r/c feb. 05. 2005 / rev. 0.0 http://www.ad-tech.co.kr 3/4 electrical specificatio ns s p eci ficat i ons hol d o v er t h e r eco m m e nded operat i ng c o ndi t i o n s , u n l e ss o t herwi s e no t e d her e i n . all values are at 25 ? and v cc=5.0v . symbol min. typ. max. unit conditio n s parameter icc --- 1.2 2.5 ma iin = 0 u supply current i in 300 - 800 ua vin = 0 v max. input current av 85 95 110 db fin=37.9khz , vin=30 o p-p wh en agc is off. max. voltage gain f bw - 4.0 6.0 khz -3db bandwidth vin=30 o p-p bpf bandwidth t pw1 500 - 800 k fin=37.9khz , burst wave vin=500 o p-p note*1 output pulse width t pw2 500 - 800 k fin=37.9khz , burst wave vin= 50m v p-p note*1 v ol - 0.2 0.4 v isink=2.5ma low l e vel output volt a ge v oh 4.8 5.0 - v - high leve l output volt a ge note 1 : (input burst wave for m ) (output pulse) 60 0 k c a rrier frequency : 37 .9 khz 60 0 k 60 0 k 60 0 k 60 0 k
ADT2450 5v operating ir receiver with excellent noise performance for r/c feb. 05. 2005 / rev. 0.0 http://www.ad-tech.co.kr 4/4 application guide 1. exa m pl e of module(37.9khz) pac k aging using ADT2450 2. functiona l guide of ADT2450 -. ADT2450 has high gain a m pli f i e r for high sensitivity. so if you want bet t e r chara c t e ristic of re ceivable distanc e , you hav e much c a re ful att e ntion in bonding of gnd pad s and s hielding to gnd. -. for m o r e bet t er dist anc e per f orma nc e, i t is i m portant to suppress the supply noise. the supply fil t er r 1 ,c 1 have to be loc a t e d c l ose to ic if possible. -. the photo diode are the i m port a nt factor in i r rec e iver module and you select it considerat el y. -. in packa g ing of ir module, the photo lens is good for re ceiving of photo signal. but i f the chip is incl uded in the l e ns, the chip also rece ive s the photo signal and the signal a c ts as a noise in the chip. so when you design the l e ns or module fra m e , the above point must be considered. -. in the de tec tion or de modulat i on( wave shape) of incoming signal, ADT2450 need the mi ni mum burst length of modul at ed signals. the inc o ming photo signal is m o dulat ed w ith proper carri er signal(e.g.37.9khz) a nd if the ?1? d ata bit is modulate d with carri er signal, the period of dat a bit?1? is i m portant. be cause the c a rrier signals is in this period, in the integr a t or & wave shape block of ADT2450 the int e gration need mini mum period to the reach of appropriately level. henc e t h e mini mum burst length is i m portant chara c t e ristic and spe c i f ica tion of re mote control syste m s. the mini mu m burst length of ADT2450 is about 10~11 c y cles of carr i er. (~10~11*tfc) you can easily unde rstand as see the figure 1. in fc set pins gnd vcc out s1 s2 s3 s4 vcc out gnd ADT2450 c 1 : 4 . 7uf r 1 : 1 00o hm figur e 1. (integrator output) bu rst len g th c a rrier frequency : 37 .9 khz (output pulse) (input burst wave for m ) t h e mi n i mu m bu rst len g th * the m i n. burst length o f ADT2450 : ~10-~11cycle s of carr ier ( ~ 10~11*tfc)
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