ec5 575a 1 4 + 1 c h annels v o l tag e b u ffer w i th otp/ocp fo r tft lcd e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 1 / 6 fe a tures ? w ide supply vo lt age range 6.5v ~ 18v ? rail - to - rail o u t p u t sw i n g ( t he hi gh e s t t wo stage & l ow e st two sta g e) ? high slew rate 30 v/s for vcom buffer ? 30 m hz - 3 d b b a n d w idt h fo r vco m b u ff e r ? ov e r tempe rat u re p r o te ctio n (o t p ) ? over current prot ection (ocp) ? larg e vco m driv e current : 100m a (ma x ) ? ultra - sm a ll package tqfp - 48 a p p l i c a tions ? tft - lcd reference driver general description t h e e c5 5 7 5 a is a 1 4 + 1 ch a n n e l v o lta g e b u ff e rs t h a t b u ff e rs re f e ren c e v o lta g e f o r g a m m a co rr e ctio n in a th in fi l m tra n sist o r li q u id cr y sta l d ispla y (t ft l cd ). t h is d e v ice inco rpo ra tin g a v co m a m p li f ier cir cu it , f o ur rail to r a il b u ff e r a m p li f ier cir cu its (t h e h ig h e st tw o st a g e and low e st tw o sta g e ) a n d 1 0 b u ff e r a m p li f iers cir cu its. the e c55 7 5 a is a v a il a b le in a sp a c e sa v ing 48 - pi n t qf p p a cka g e , an d th e o p e ratin g te m p e rat u re is f ro m C 2 0 c to + 8 5 c. p in a s s i gn m e nt the EC5575A is a 1 4 +1 channel volta g e buffers that buffers reference voltage for gamma correction in a thin fi l m transistor liquid crystal display (tft l cd). this device inco rporating a vcom amplifier circuit, f o ur r ai l to r ai l b uf f er a m pl i f i er c i r c ui ts (the highest two stage and lowest two stage) and 1 0 buffer amplifiers circuits. the EC5575A is available in a s pace saving 48 - pi n tqf p package , an d th e operating temperature is from C 20c to +85c. ? s up ply v oltage r ange 6v ~ 18v ? rail - to - r ail o utput voltage s wing ? high s lew r ate --- vcom buffer 30v/s --- gamma buffer 2 v/s ? thermal shutdown protection ? short - ci r c ui t current limit protection ? continuous output driv e current --- vcom buffer 100 m a (ma x ) --- gamma buffer 3 0m a (ma x ) ? ultra - sm a ll package tqfp - 48 l(exposed pad) http://
ec5 575a 1 4 + 1 c h annels v o l tag e b u ffer w i th otp/ocp fo r tft lcd e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 2 / 6 orde ring informa tio n part no. t op mark package d e scription EC5575A nght as15 - hf yyww t lllllll l tqfp - 48 l ( exposed p ad ) yyww is date code, lllllll is lot no. t tracking code
ec5 575a 1 4 + 1 c h annels v o l tag e b u ffer w i th otp/ocp fo r tft lcd e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 3 / 6 parameter de s cription conditi o n min t y p max units input c h ara c teristi c s v os input offset voltage v c m = 0v 2 12 mv tcv os average offset voltage dr i ft [1] 5 v/c i b input bias c u rr e nt v c m = 0v 2 50 na r in input imped a nce 1 g c in input ca p aci t ance 1.35 pf outp u t c h a r act e ristics v ol output swing low i l = - 5ma (a, b, m , n, com buffers) - 4.92 - 4.85 v v oh output swing high i l = 5ma (a, b, m , n, com buffers) 4.85 4.92 v v ol output swing low i l = - 5ma (c ~ l buffers) - 3 .5 v v oh output swing high i l = 5ma (c ~ l buffers) 3.5 v i sc( a~n ) short cir c uit current (a ~ n buffers) 120 ma i ou t ( a~n ) output current (a ~ n buffers) 30 ma i sc(c o m) short cir c uit current (com buff e r) 300 ma i ou t (com) output current (co m buff e r) 100 ma p o w e r supp l y performance psrr p o w e r s u pp l y reject i on r a tio v s is moved from 3.25v to 7.75v 60 80 db i s ( a~r ) sup pl y curr e nt (per amplifier) no l o ad (a ~ n buffers) 500 750 a i s (co m) supply current (com buffer) 3 ma d y namic pe r forman c e sr a~ r slew rate [2] - 4.0v Q v ou t Q 4.0v, 20% to 8 0 % 2 v/s sr com slew rate [2] - 4.0v Q v ou t Q 4.0v, 20% to 8 0 % 30 v/s t s settling to +0.1% (av = + 1 ) (av = + 1 ), v o =2v step 5 s bw a~ r - 3db ban d w i dth rl = 1 0 k , cl = 10pf 2 mhz bw com - 3db ban d w i dth rl = 1 0 k , cl = 10pf 30 mhz pm phase m arg i n rl = 1 0 k , cl = 1 0pf 60 degrees cs ch a nnel se p aration f = 1 mhz 75 db temper a tu r e performa nc e temp ther m al shu t d o w n 150 1. meas u r e d over op e rati n g temperature ran g e 2. slew rate i s me a s u re d o n risi n g and f alling ed g es absolute m ax i mum r a tings ( t a = 25 c) v a lue s b e y o n d a b so l u t e max im u m r a tin g s m a y ca u se p e r m a n e n t d a m a g e t o t h e d e v ice. th e se a re stre ss ratin g s o n ly ; f u n ctio n a l d e v ice o p e rat io n is not im p li e d . exposure to amr conditions for extended periods may affect device reliabili t y. su p pl y v o lt a g e be t w e e n v s+ a n d v s - +18v storage t e mperature - 65c to +150 c input volt a ge ( for rail - to - ra i l ) v s - 0.5v, v s + 0.5v operati n g t e mperatu r e - 4 0c to +85c maximum con t inuous output current (a ~ n b uffers) maximum c o n t in u ous output current( c om b u ffer) maximum d i e t e mperature 30ma 100ma +150c le a d t e mperature esd voltage 260 c 2kv im port a nt not e : all paramet er s having min / max sp e c ific a tions are gu a ranteed. typical values a re for informati o n pur p oses o n ly . unless ot h erw i s e n oted, all tests are at the sp e c ified temp e rat u re and a re pu lsed t e sts, theref o re: t j = t c = t a el ec t r i c a l c h a r a c t er i st i cs v s + = +5v, v s - = - 5v, r l = 10k ? a nd c l = 1 0 pf , t a = 25 c u nless o the r w ise specif i ed.
e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 ec5 575a 1 4 + 1 c h annels v o l tag e b u ffer w i th otp/ocp fo r tft lcd 4 / 6 applic a tions inform a t ion product de s cription the EC5575A rail - t o - rail 1 4 +1 cha n ne l voltage buffers are built on an a d vanc e d high voltage cm o s process. its beyond rai l s input c a pabili t y and full sw i ng of output ran g e made itself an ideal amplifier for use in a wide ran g e of g e n era l - p u rp o s e appl i c atio n s . the feat u r e s of high s lew rate ( vcom: 30v/s , gammas: 2 v/s) , fa s t s ettling time, high unity - gain bandwidth ( vcom: 30 mhz, gammas: 2mhz ) as well as h igh ou t put driving capability have proven t h e EC5575A a g o o d voltage ref e re n c e b uffer i n tft - lc d for grayscale r e fere n c e appl i c atio n s . high ph a se m a rgin and extr e m e ly low p o w e r co n s u m ption ( vcom: 3ma, gammas: 500a) m a ke the EC5575A ideal f o r c o n n e c ted in voltage foll o wer m o de for low pow e r high drive ap plicati o ns . s u p p l y v o lt age , inp u t r a n g e and o u tput s w i n g t he e c557 5a c a n be o p erate d w i t h a s i ng l e nom i na l w i de s u pp l y v ol t a ge r an g i ng f r om 6v to 18v wi t h s tab l e p e r f or m an c e ov er ope r ati ng tem pe r atu r e s o f - 2 0 c t o + 8 5 c. w i th 5 0 0m v great e r th a n r a i l - to - r ai l i n pu t c om m o n m od e v o l ta g e r an ge a n d 7 5d b of com m o n mo d e rej e c ti o n r a t i o, the e c5 57 5 a al l o w s a w i d e r a nge se n s i n g am o ng m an y a p p l i c at i o n s wi t ho ut ha v i ng any co n c e r n s ov er ex c ee d i ng th e ra n ge a n d no c om p r om i s e i n ac c u r a c y . t he out p ut s wi n g s of the e c5 57 5 a t y p i c al l y ex ten d to w i t hi n 8 0 m v of po s i ti v e a nd n eg at i v e s u p p l y r ai l s wi t h lo a d c urr en ts of 5m a . t he out p ut v ol t ag e s w i n g c an b e ev en c l o s er to t he su p pl y r a i l s b y m erel y d ec r e as i ng the l oa d c u rr e nt. f i gu re 1 sh o w s t h e i n pu t an d ou t p ut w a v ef or m s f or the de v i c e i n th e u ni t y - ga i n c o nf i g urati on . t he amplifier i s o perat e d un de r 10 v supply with a 1 0 k and 10pf load co n n e c ted to gnd. the input is a 10vp - p sin u so i d. an approximately 9.985 v p - p of o utp u t voltage swing can be e asily achiev e d. figure 1. ope r ation w i t h r a i l - to - rail i n put a n d output outp u t sho r t circuit cu r rent li m it a n output sh o rt cir cuit current ( vcom: 30 0ma , gammas: 120ma ) will be limited by the EC5575A if the output is dir e c t ly short e d to the positive or the n e gative su p ply. for an indefinitely output sh o rt circuit, the p ow e r d i ss i pa t ion could ea s ily incre a se s u ch that the device may be dam a ged. the inter n al metal interc o nn e ctio n s are well d e sig n ed to prevent the output c o ntinuo u s current from exceedi n g 3 0 ma for gammas and 1 0 0 ma for vcom such that the maxi m um reliability can be well maintained. outp u t pha s e re v ersal the EC5575A is desig n ed to prevent its output fr o m being p h a s e reversal as l ong a s the i n put voltage is limited from v s - 0.5v to v s+ 0.5v. figure 2 sh ow s a photo of the device o u tput with its input voltage driven b eyo n d the supply rails. althou g h the ph a se of the dev ice ' s output will not be reversed, the input's over - volt a ge sh o uld be avoided. an impro p er input voltage exc e eds su p ply r a nge by m o re t han 0.6v may result in an ov er str e ss d a mage. figure 2. o p eration w i th b e y ond - the rails input p o w e r diss ipation the EC5575A is d e si g ned f or maxim u m output curre n t ca p ability. even though m oment a ry output sh o rted to gro u nd ca u s e s little dama g e to the device. f or the hi gh dri v e a m pl i f i er e c5 57 5 a , it is p o s s i bl e t o ex c e e d th e 'a bs o l ute - m ax i m u m ju n c ti on tem pe r a ture' un d e r c ert ai n l oa d c u rr e nt co n di ti o n s . t he r e f o r e, it i s i m po r t a nt to ca l c ul a te the m ax i m u m ju n c t i on tem pe r atu r e f or th e ap p l ic ati o n to de term i ne i f l oa d c o n d i ti o n s n e ed to b e m o di f i ed f or t h e am pl i f i er to r em a i n in t h e s af e op e r ati n g are a. t he m a x i m u m po w er d i s s i p a ti o n a l l o wed i n a p a c k a g e i s det e r m i n ed ac c ordi ng to : p d m a x = t j m a x - t a m a x ja
e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 ec5 575a 1 4 + 1 c h annels v o ltage buffer with otp/ocp fo r tft lcd 5 / 6 wh e r e: t jm ax = m ax i m u m j un c ti on t e m pe r atu r e t a m ax = ma x i m u m a m bi e n t t e m pe r atu r e ja = t h e rm a l res i sta n ce of the packa g e p dmax = maximum pow e r dissi p ation in the package. the maxim u m pow e r diss i pation act u ally produced b y an ic is t h e total qui e s ce n t supply current times the total pow e r supply voltag e , plus the po wer i n the ic due to the lo a ds, or: p d m ax = i [ v s * i s m ax + (v s+ C v o ) * i l ] wh e n s o urci n g, and p d m ax = i [ v s * i s m ax + ( v o C v s - ) * i l ] wh e n s i n k ing. wh e re: i = 1 to 15 v s = total supp ly voltage i smax = maximum supply current per a mplifier v o = maximum output voltage of the a p plicati o n i l = load current r l = l o ad r e sist a nce = ( v s+ C v o )/ i l = ( v o C v s - )/ i l a calculati o n for r l to prevent device from over h eat can b e eas i ly solved by sett ing the two p dm a x equati o ns eq ual to each other. dri v ing ca p aciti v e loads the EC5575A is desig n ed to drive a wide r a nge of ca p acitive l o ads. in a dd ition, the output c u rrent handl i ng ca p ability of the device all o ws f o r go o d sl e wing c h aracter i stics ev en wi th large cap a citive loa d s. the combinati o n of these features m a ke the EC5575A ide a lly for applications s u ch as tft l cd panel gra y scale refer e nce voltage buff e rs, adc i n put amplifiers, etc. a s l oa d c a p ac i t a n c e i n c r e as es , h o w e v er, the - 3 d b ban d wi dth o f the d e v i c e wi l l d e c r e a s e a nd t h e pe a k i ng i nc r e as e. dep en d i ng on the ap p l i c a ti o n, i t m u s t be ne c es s ar y to r ed u c e pe ak i ng a nd t o i m prov e de v i c e s tab i l i t y . t o i m prov e de v i c e s tab i l i t y , a s m al l v a l u e o f s er i es r es i st o r ( us ua l l y b et w e en 5 a n d 50 ) must be pl a c ed in ser i es with the output. the advant a ge is that it improv e s the settling a n d overshooti n g perf o rma n c e with very large capacitive loads. figure 3 sh ow s the t ypical a pplication c onfiguration . figure 3 . typical applica tion configuration. p o w e r su p p l y b y p as si n g and p r int ed ci r cuit bo ar d l a y out with high p h ase m a rgin, the EC5575A perfor m s stab l e gain at high freque n cy. like any high - freq u e n cy device, g o od l ayout of the p rinted circuit board u s ually com e s with optimum p e rforma n c e. g rou n d pla n e co n s tr u c tion is highly recomme n ded, l ead le n gt h s sh o uld be as sh o rt as possible and the power s u pply pins m u st b e well byp a ssed to r e d u ce the r i sk of oscillation. fo r normal sin g l e supply operation, where the v s - pin is conn e cted t o ground, a 0.1 f ceram i c ca p acit o r sh o uld be placed from v s+ pin to v s - pin as a byp a ss i ng ca p acit o r. a 4. 7 f tantal u m c a p a citor sh o uld then be co n n e c t e d in parallel, placed in the regi o n of the amplifier. one 4.7f ca p acitor may be us e d for m ultiple dev ic es. th i s s a me cap a cit o r comb i nation sh o uld be p l ac e d at each supply pin to gro u nd if split suppl i es a re to be us e d.
e - cmos corp. (ww w .e c mo s . c om.tw) 3k29 n - rev. f 001 ec5 575a 1 4 + 1 c h annels v o ltage buffer with otp/ocp fo r tft lcd 6 / 6
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