Low-pass filter for UWB system with the circuit for compensation of process induced on-chip capacitor variation

Transcription

1 Oiginal scienific pape Low-pass file fo UB sysem wih he cicui fo compensaion of pocess induced on-chip capacio vaiaion Banislava Milinković,, Milenko Milićević,, Đođe imić, Goan ojanović, Radivoje Đuić TE Eleconic oluions GmbH, uga, Gemany Univesiy of Novi ad, Faculy of Technical ciences, Depamen fo Powe, Eleconic and ommunicaion Engineeing, Novi ad, ebia Univesiy of Belgade, chool of Elecical Engineeing, Depamen of Eleconics, Belgade, ebia Absac: This pape descibes he design and opimizaion of a hebyshev 5h ode low pass file wih included cicui fo auomaic pocess calibaion and compensaion The file is ealized using lumped elemens in 0 nm adio fequency (RF) MO pocess and is dedicaed o cove lowe sub-band (4 GHz 48 GHz) of ula-wideband (UB) sysem The poposed full on-chip calibaion concep esimaes -apacio (Meal-Insulao-Meal) capaciance pocess-induced vaiaion agains moe sable on-chip MO capacio efeence In ode o esimae he capaciance value, a low fequency oscillao is designed, which uses boh ypes of capacios fo geneaing he oscillaions, one afe anohe The capacio value is deemined in digial domain based on he aio of wo oscillaion fequencies and is exac needed value is obained using a compensaion capacio bank Deailed mahemaical opimizaion of he calibaion mehod is pesened All RF, analog and digial cicuis have been inegaed on a es chip and fabicaed in 0 nm RF MO pocess The poduced Is have been on-wafe measued and compaed o simulaion esuls Accoding o obained esuls, he poposed calibaion concep lowes pocess-induced file ansfe chaaceisic vaiaion fom appoximaely 5 db o 06 db a he ciical fequency The calibaion needs o be applied jus once a he beginning of cicui opeaion The oal aea of implemened calibaion cicui is less han 0 mm The same mehod and he compensaion cicui can be employed fo he calibaion of all on-chip cicuis whose pefomance is affeced by capaciance pocess vaiaion Keywods: pocess vaiaion; compensaion; capacio; low-pass file; UB Nizko pasovni file za UB sysem z vezjem za kompenzacijo pocesno vzpodbujenega speminjanja inegianega kondenzaoja Izvleček: Članek opisuje opimizacijo hebyshevega nizkopasovnega fila peega eda, ki vključuje vezje za avomasko kalibacijo in kompenzacijo File je ealizian z upoabo 0 nm MO pocesa in je namenjen za podpas (4 GHz 48 GHz) UB sisema Pedlagan polno inegian koncep kalibacije ocenjuje spemembe kapaciivnosi kondenzaoja v naspoju s sabilnim efeenčnim MO kondenzaojem Za oceno kapaciivnosi je upoabljen nizkofekvenčni oscilao Opavljena je bila naančna maemaična opimizacija kalibacijske meode RF, analogna in digialna vezja so inegiana na esnem čipu v 00 nm RF MO ehnologiji Čipi so bili mejeni na ezini Glede na ezulae pedlagana kalibacija zmanjšuje pocesno požen penos kaakeisike spememb za 06 do 5 db pi kiični fekvenci Isa meodologija se lahko upoabi za vsa vezja, ki so obemenjena s spemembami kapaciivnosi Ključne besede: vaiacije pocesa; kompenzacija; kondenzao; nizkopasovni file; UB Jounal of Micoeleconics, Eleconic omponens and Maeials Vol 45, No 4 (05), * oesponding Auho s banislavamilinkovic@es-dscom 66 MIDEM ociey

2 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), Inoducion onsan I manufacuing echnology scaling allows he device inegaion in eve smalle aea As an advese effec, he size educion causes degadaion of he ininsic pecision of he manufacued componens [] In ode o saisfy exeme design consains on he analog/rf cicuis wih given componen oleances, some mehod of digial calibaion mus be applied [] Fo he mass poduc soluions, i is vey impoan ha he calibaion cicuis ake as small aea on he silicon as possible ince wih he echnology scaling he size of digial devices is educed, i is possible o implemen complex digial calibaion cicuis occupying vey small on-chip aea Moeove, fo consume poducs, exenal efeences ae no applicable, since he exenal componen size is almos compaable o he chip size [] In his pape, he design of a passive, L low-pass file is descibed The D inducance value fo on-chip inducos is mosly insensiive o pocess vaiaions [], bu on-chip capacios noably change hei values due o he finie manufacuing accuacy The Table pesens capacio value vaiaions fo hee ypes of capacios, available in he used echnology The -capacios ae he mos suiable fo RF applicaions, since hey ae he mos linea and have he highes Q-faco of all available on-chip capacio ypes, so his ype of he capacio is chosen o be used in he design In case of -capacios, he shif in capaciance occus mosly due o he oxide hickness vaiaion, ahe han o he empeaue-induced vaiaion Unfounaely, he shif in he capaciance value will degade he final pefomance of cicuis beyond allowed limiaions, so an adequae calibaion and compensaion mehod mus be applied Pesened calibaion concep compensaes -capacio vaiaion and can be applied in any cicui which chaaceisics ae deeioaed due o cap pocess-induced vaiaions Table : Toleances of he available capacios in he used echnology apacio ype Pocess and empeaue (-40:5 ) oleance ±5% MOM ±5% MO ±4% The Pape [] has demonsaed a way o esimae and compensae capacio values using an exenal efeence In [], he calibaion concep wih he inenal on-chip efeence has been poposed, which makes calibaion suiable fo he small fom faco soluions The pice is paid by limied accuacy of he efeence, bu a he ohe hand, he appoach is insensiive o paasiic and sysemaic eos inoduced by calibaion cicui This pape combines hese wo calibaion appoaches wih addiional opimizaions, offeing unique calibaion soluion, applicable fo mass poducion The poposed soluion is applied on he lowpass file calibaion The concep is veified hough measuemens The second secion descibes low-pass file implemenaion In he hid secion, he calibaion concep is eviewed in deail The expeimenal esuls ae pesened in he fouh secion ha is followed by conclusion in he fifh secion Low-pass file Descipion Ula ideband (UB) sysems ae vey suiable fo low cos, low powe o high daa ae, sho ange communicaion By using a lage bandwidh, hey ae immune o naow band inefeence and mulipah fading These sysems ae pefeable in he applicaions ha demand high secuiy level, since ansmied signal is noise-like, and hence had o inecep Files ae one of he key componens in UB sysems In ansmie, hey conol ou-of-band adiaion and suppess highe hamonics In eceive, files enable he suppession of unwaned signals and inefees Poposed file is designed fo he lowe band of UB sysem accoding o 8054a sandad [4] The file can be applied in boh, ansmie and eceive The specificaions of he poposed 5 h ode hebyshev low-pass file ae lised in Table The specificaions ae chosen based on ansmie ansmission powe level and lineaiy and esimaed levels of unwaned signals and inefees in image band on he eceive side The hebyshev file has he bes compomise beween pass-band ipple, which degades Eo Veco Modulaion (EVM) and seleciviy, which limis ou-ofband emission and ecepion Table : File specificaions Iem Value Descipion Zin 50Ω Zou 50Ω <-0dB 67

3 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), <-0dB IL < db Goal Ode 5 hebyshev Ripple ±05dB Fc 48GHz db poin eleciviy -5dB @067GHz The fis file implemenaion has been synhesized using ideal componen values fom [5] Due o he low Q-faco of he on-chip passive componens, opimizaion of componen values unde nominal condiions has been pefomed The file schemaic and obained -paamee simulaion esuls hough all hee pocess vaiaion cones ae pesened in Figue and Figue, especively The esuls ae obained on he schemaic level and exaced paasiic effecs afe he cicui layou will inoduce addiional losses RF IN PAD Figue : LPF- schemaic L L RF OUT PAD alibaion In his secion, he calibaion concep using inenal efeence is descibed in deails The mos suiable inenal efeence fo on-chip capacio calibaion can be obained using MO capacios As i can be seen fom he Table, he vaiaion wih a pocess and empeaue is accepable ±4% Bu MO capacios ae vey nonlinea and can be used in he cicuis wihou appopiae polaizaion Fo he pupose of he calibaion, he efeence MO capacio is polaized in he egion whee is nonlinea behavio is negligible oncep Each of hee capacios fom Figue is eplaced wih a bank of one base and seveal uning capacios, used fo he compensaion Depending on pocess vaiaion effecs on he capaciance value, he coesponding compensaion capacios ae included o excluded fom he cicui opeaion using RF swiches, Figue Thus, he effecive capaciance is adjused o he nominal value unde all pocess vaiaions onol signals fo he swiches ae geneaed fom he cicuis ha esimae capacio pocess vaiaion ' nom TRL M M M TRL TRL Figue : apacio bank Figue : File ansfe chaaceisic in slow(blue), ypical(geen) and fas(ed) cone Figue 4 illusaes he concep of -capacio value esimaion The oscillao coe geneaes oscillaions on chage-pump pinciple using fis he and han he MO capaciance The -capacio value is calculaed in digial domain by deemining aio of he oscillaion fequencies which coesponds o invese aio of he and MO capacio values As i can be seen fom Table and Figue, he specificaions ae no fulfilled unde all pocess vaiaions One way o ovecome his poblem is o incease he ode of he file Tha leads o ovedesign a he pice of lage chip aea Anohe soluion is o apply a calibaion and his soluion is he pefeed one UP V DON V O coe V UP/ H DON UP 0 V h v IN DON v IN I B I B MO DIGITAL NETORK TRL LK _ MHz FLT 5 0 5dB 48GHz Figue 4: alibaion concep The eal advanage of he poposed appoach is cancellaion of PVT (Pocess, Volage and Tempeaue) 68

4 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), vaiaions fo all componens used fo fequency aio deeminaion since he same oscillao coe geneaes oscillaions in boh cases (wih and MO capacios) Values of he capacios in he cap bank and he pocess values a which hey ae included in he cicui opeaion ae chosen accoding o he calculaion deived in [] New value of he nominal capacio is: ε = () ' nom nom kmax hee nom is he capacio nominal value, ε is maximal accepable eo caused by discee naue of compensaion and k max is maximal pocess value- k max = σ, whee σ is nomalized sandad pocess deviaion fo -capacios New, n-h compensaion capacio () is included in he cicui opeaion a he pocess value given by means of () I is assumed ha nom is Noe, ha a k n pocess value, only n is included in he cicui opeaion n k n ε ( ε ) = n () σ ( ε ) ε n ε i k i= n = max aisfacoy accuacy of up o ε=% can be eached using hee compensaion capacios Nomalized values of he compensaion capacios ae pesened in Table All capacio values ae nomalized o nom Table : Nomalized values of he compensaion capacios in cap bank pesened in Figue apacio name apacio value nom wich design ompensaion capaciances ae included in he cicui opeaion via RF swiches as pesened in he Figue The swiches ae opimized so ha he bes compomise beween inseion loss (when he swiches ae on ) and isolaion (when he swiches ae off ) is obained fo he given applicaion () On sae hen he swich is on, he gae volage coesponds o V DD, while V D = V =0 The impedance seen beween dain and souce eminals of he ansiso is dominaed by ds esisance, (4) Z ON µ ox L ( V V ) h DD Fo he minimal ansiso lengh and he fixed polaizaion we can assume ha swich on esisance is appoximaely R ON K R /, whee K - =µ 0x (V -V )/L is R DD h consan This appoximaion is good enough in he obseved case In ode o calculae conibuion of he swich on esisance o he file inseion loss, we need o ansfom impedances (Figue 5) R P = R ( Q ), P = Q, Q = Q ω R Figue 5: A seies o paallel impedance ansfomaion Fo Q>0 we ge: R P R Q, P ince we have hee swiches in he cicui, he oal conibuion of he swich on esisance o he node impedance can be expessed via equivalen paallel esisance, (7) Influence of he swich on esisance on file pefomance is measued by means of Q-faco Equivalen Q-faco of he obseved node has he lowes value in he case when all hee swiches ae on This case coesponds o he fas cone (k=k min ) R eq Q R Q (4) (5) (6) = R R Q (7) In ha case, he equivalen Q-faco of each capacio can be expessed by (8) Q = ω k min R P 0 K R ( RP nom hee i coesponds o i / nom aio fo i=,, and 0 = / These values ae lised in Table ω is nom nom ) (8) angula fequency, k min is minimal pocess value, nom 69

5 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), is nominal capacio value, K R is swich consan expessed above and i is widh of he i-h swich which includes he compensaion capacios i ino he cicui opeaion Off sae Figue 6 pesens swich paasiic capacios in off sae gd and gs ae oiginaing fom ovelap of he gae poly and dain/souce aeas and hey can be appoximaely expessed via gd = gs = ov = L ov ox db and sb ae juncion capaciances beween dain/souce eminal and subsae This capaciance is usually decomposed ino boom plae capaciance, associaed wih he boom of he juncion, j and sidewall capaciance due o he peimee of he juncion, jsw j and jsw ae capaciance pe uni aea and uni lengh, especively, and boh can be expessed as j = j0 /(V R /ф B ) m, whee V R is evese volage acoss juncion ф B is he juncion build-in poenial and m is ypically in he ange of 0 and 04 [6] In ode o make hese capaciances as low as possible, muli-finge sucue is adoped and he dain is conneced o he supply volage in swich off sae The swich polaizaion, as pesened in Figue, is done via invee and a high value esiso The esiso inceases oupu invee impedance since i appeas in paallel wih swich off impedance hee is ansiso widh, E is widh of he diffusion a dain eminal, L ov is deemined by he echnology and epesens lengh of an ovelap aea beween gae poly and dain diffusion aea, while is oxide capaciance pe uni ox aea ih he adoped polaizaion, we can appoximaely conclude ha he dain capaciance is deemined wih he echnology paamees and ansiso widh, dain K Noe ha in he fequency ange of inees (up o 0GHz) and wih a good layou we can neglec R sub in a given echnology Also />>E is assumed apacio eo (ε p ) due o he swich paasiic capaciance is lages when all swiches ae off and ha occus in slow pocess cone k=k max (9) (0) sb gs G R b gd db D wich opimizaion ihou compensaion, he IL (Inseion Loss) is deemined by Q-faco of he inducos ih he compensaion pesen, he swiches can significanly degade he IL In ode o peven i, equivalen capacio Q- faco has o be high enough a he fequency ange of inees B Figue 6: wich in off sae R sub models he subsae esisance fom he juncion o he subsae gound and in he given echnology i depends on size and disance of he subsae conacs, he ansiso size, he numbe of he gae finges, and even of neaby cicui elemens [7] ih he given polaizaion and muli-finge sucue and wih neglecing R sub he impedance seen fom he dain eminal is mainly capaciive and given by means of he following fomula: Accoding o (8) equivalen capacio Q-faco deceases wih a fequency Thus, inseion loss will be he mos degaded a he highes fequency whee i is impoan: a cuoff fequency (ƒ=ƒ c =48GHz) Based on simulaion esuls ha conside degadaion of IL due o equivalen capacio Q-faco degadaion, i is found ha fo capacios having Q-faco above 40 a f c, he degadaion will be lowe han 05dB Fom (8) we can obseve ha ansiso widh should be maximal in ode o have high Q-faco Fom he ohe side, he widh should be minimal fo he minimal eo, (0) so, he opimal ade-off beween inseion loss and capacio eo needs o be made The calculaion below gives he opimum aio of swich widh fo a given Q-faco 70

6 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), The goal is o minimize ε p fo a given Q Fo he deivaion we ae going o use Jesen s inequaliy- x, x, x : f ( x ) f ( x ) f ( x) f ( x x x) hee ƒ is a convex funcion, x, x and x in is domain,, and posiive weighs fo which applies = Equaliy applies if and only if x = x = x o ƒ is linea Fo ƒ(x)=/x, we can wie: () cos of highe IL Fo Q =40 we obain maximal eo of ε p % which is accepable Fo he capacio he swiches ae sized fo hese values Fo and we ae esiced wih he minimal size of swiches in he used echnology In his case, Q =5 fo ε p % Noe ha he wos IL degadaion and maximum eo aise in he case of diffeen cones Fo seleced swich widhs, he IL degadaion a f c is below 06 db ompensaed file The compensaed file is simulaed on he exaced level hough fas, ypical and slow cones and obained -paamee esuls ae pesened in Figue 7 = Fom (0), () and () we can obain: ε p k max kmax K nom ( Using (8) we can ewie (): ε k p k k max max min K ) 0 ω K Q R () () (4) a) Fo consan Q a f c, he expession fom he igh side in (4) is consan Noe ha he expession doesn vay wih he fequency, since i cancels ou Minimal eo can be obained in he case when he lef and he igh side of (4) ae equal I will be he case if and only if: k K max nom max nom max nom = = (5) k K e can han ewie (5) ino condiion: k K = = (6) ih specified Q-faco a f c and (6) and (8) we can obain he widhs of he swiches fo all hee capacios Noe ha wih choosing Q-faco value a f c, we deemine he capacio eo, oo o if he eo fo chosen Q-faco is no saisfacoy, one can decease i a he b) Figue 7: -paamees of he compensaed file in slow (blue), ypical (geen) and fas (ed) cone- a) b) If we compae he esuls wih he ones obained in he non compensaed case, Figue, we can conclude ha he file ansfe chaaceisic vaiaion of 5 db a he ciical fequency 64 GHz is loweed o only 06 db and he specificaions ae me unde all pocess vaiaions 7

7 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), apacio value esimaion In his secion, cicui ha geneaes conol bis fo designed swiches is descibed in deail 4 Oscillao The oscillao concep is pesened in Figue 8 and is in deail descibed in [] ingle-ended oscillao cicui geneaes oscillaions on he chage-pump pinciple Alhough he opology is moe-less he same like in [], he design opimizaion diffes a lo As noed, he design pocedue in his wok gains he benefis fom using he inenal efeence, since he accuacy of he capacio value esimaion is insensiive o he empeaue, powe supply and pocess vaiaions and on he paasiic influences of he line connecions Figue 8: Oscillao- concep Digial logic coodinaes he oscillao Digial signal osc_enb ses he oscillao in he iniial sae and enables is unning The / MO signal deemineds weahe he oscillaion ae geneaed wih o MO capaciance The signal EL in he oscillao has he ecangula shape Is fequency coesponds o he oscillaion fequency and is measued in he digial domain The oscillaion peiod is popoional o he value of he measued capaciance, (7) T / MO / MO V / MO ( V V ) = = (7) I I B In digial domain, he oscillaions using each of capacios ae couned wihin pedefined measue ime, T measue OUNT OUNT OUNT V V V MO 700 / MO V 800 mv V 600 mv EL VMP ELN VMPN UP / DON MO Tmeasue / = (8) T MO T = T MP mv MP Q R Qn _ ideal MO _ ideal ELN EL NON_OVER / MO ( α ( α MO ) = ) UP / DON VMPN VMP DON /UP MO B α α MO MO (9) In (9) α and α MO model he oscillaion peiod deviaions fom he nominal values caused by non-idealiies; namely, inaccuae on-chip cuen souce, non-ideal UP DON Vdd I B I B / MO MO / V V MO MO cuen mioing, offse of opeaional amplifies, V and V vaiaions, paasiic capaciance and esisance of he connecion lines ince non-idealiies ae almos he same in boh cases of oscillaions due o he same oscillao coe, follows ha α α MO Volages V and V have o be high enough ha nonlinea behavio of MO capacio does no affec he calibaion accuacy Fom he ohe side, hese volages have o be low enough, so he P side of cuen mios has high oupu impedance Poposed calculaion shows he influence of V and V volages on he esimaion eo caused by MO cap non-lineaiy Accoding o AM (Advance ompac MOFET) model, gae capaciance, fo V D =0, can be expessed by means of () [9] gae = gs gd gb (0) gae n IF = 0 x 0x () n n IF [ IF ln( IF ) ] VG VT 0 V, D = φ () n ' n = n( V ), = L, φ 6mV ( = 7 ) () G ox 0x In (), 0x is gae oxide capaciance, n is so-called slope faco and is a funcion of gae volage, IF is invesion faco which can be calculaed using () In (), V T0 is heshold volage, Φ is hemal volage and V G, V and V D ae ansiso gae, souce and dain volages Fo he chosen value of MO capacio and high enough V G, he ox is deemined Using he pocedue descibed in [9] we can exac paamees V T0 and n(v G ) Fo V D =V =0 fom (), we can expess IF and subsiue i in () Now we ae obaining he gae capaciance as a funcion of gae volage, gae = gae (V G ) ih his expession, we can calculae deviaion of T / T MO aio in nominal condiions fom ideal (T /T MO =) as a funcion of V G Using (4) we can expess volage acoss MO cap (gae volage) as a funcion of ime e ae assuming ha capacio chages fom volage V wih consan bias cuen, I B I dv = gae( v ), v (0) V (4) d B = Fom (5) we can find ime needed o chage obseved cap fom V o V, namely T MO (V,V ) v ( MO V ) = V T ( V, ) (5) 7

8 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), In ode o have ideal aio T /T MO =, we ae choosing: gae( V ) gae( V ) = (6) ombining (7) and (6) we can expess T =T (V, V ) ih ha and (5), we can expess eo (T /T MO - ) 00% in espec o V i V The absolue eo is depiced in Figue 9 as he funcion of V fo V =V 0 V, V =V 0 V and V =V 0 V As can be seen fom he Figue 9 he eo caused by MO cap non lineaiy is negligible fo V >06 V fo V - V 0 V In ode o have consan cuen capacio (de)chaging, which is assumed duing all calculaions, cuen mios should have high oupu esisance Fuhemoe, T osc / should be lage han clock fo digial logic unde all PVT vaiaions in ode o synchonize and sense he oscillaions in digial newok The nominal values of /MO =0 pf, I B =00 µa, V =06 V and V =08 V allow hese condiions o be ealizable wih he accepable aea of he oscillao Figue 9: Eo in cap value esimaion due o he finie MO cap lineaiy vesus V, fo V =V 0 V (geen), V =V 0 V (puple) and V =V 0 V (blue) changes a lo, due o he full on-chip implemenaion The obained fequencies ae in he ange fom 7MHz o 54MHz Figue 0 pesens ime wavefoms of he slowes, nominal and fases oscillaions ha occu wih -capacios The oscillao wih he bias souces is fully implemened Two cuen souces ae designed, one fo he compaaos polaizaion, anohe fo he pupose of chaging and dischaging he capacios hough cuen mio The souces ae self-biased and opeae using he posiive feedback Fo each souce, chmi igge is designed in ode o povide ceain sa unde all PVT vaiaions Oscillaion fequency fo boh, MO and capacios, simulaed hough 8 diffeen PVT combinaions, Figue 0: Oscillaion wavefoms in he slowes, nominal and fases case Table 4: / MO aio fo diffeen PVT values on he exaced level Iem Vdd=4V Vdd=V Vdd=6V T [º] ORE cone cap in slow cone (ideal=5) slow ypical fas cap in ypical cone (ideal=) slow ypical fas cap in fas cone (ideal=085) slow ypical fas

9 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), Table 4 summaizes esimaed values of -capacio hough diffeen cones, supply volages and empeaues Nine diffeen combinaions of empeaue and supply volage ae consideed- when all excep ae in one cone, coe cone, and is in anohe, noncoelaed cone Esimaion eo is always smalle o equal o 6% (in 96% cases eo is 5%) 4 Digial logic ince he calibaion pocess is being pefomed only once afe powe supply is applied, he speed and he low powe consumpion of he digial logic ae no so impoan equiemens The aea should be esiced, which is no a poblem, due o low complexiy and lage level of inegaion of digial logic Figue : onol block- FM (Finie ae Machine) Block diagam of he digial logic is pesened in Figue The logic is synchonized wih an exenal clock of MHz Digial logic coodinaes he oscillao unning, deemines he aio of he oscillaion fequencies and accoding o he aio value, ses he conol bis fo he file capacio bank Figue : oune of he oscillaions and ime coune Figue : Digial newok fo geneaing file conol bis Exenal signal ese_n ses he iniial sae of he logic All exenal signals ae synchonized wih he clock in ode no o violae seup and hold imes of used flipflops, o avoid flip-flops o each measable sae hosen oscillaions ha should be measued ae pesened a he inpu po osc of he digial newok ignal cal is exenal and i sas he calibaion pocess again Oupu signals fl_cl_b[:0] conol he swiches in he file adjusable capacio bank Digial pa of he design consiss of he fou main blocks descibed by Veilog code: () ONTROL BLOK, which is he coe of he digial logic ealized as he finie sae machine, Figue ; () O_OUNTER, ha couns oscillaion in he pedefined ime peiod T measue, equaion (8); () DIVIDER, which divides OUNT MO and OUNT equaion (9); (4) FLT_TRL block, ha geneaes file conol bis accoding o he division esul The lised digial blocks ae descibed via Veilog code and ae implemened in he silicon hole logic is implemened using 450 digial gaes and akes he aea of 4µm x 0µm Afe synhesis and place-and-oue, iming and funcional checks wee pefomed 4 Expeimenal esuls- Measuemens The file wih is compensaion capacios, oscillao and digial newok ae designed and fully inegaed The layou of he whole design is pesened in Figue 4 As i can be obseved fom he figue, he compensaion capacios ae ealized wih muliple capacios conneced in seies This has been done due o he high minimal value of capacios in used echnology The effecive aea of he design is significanly smalle han he size of he enie chip The eason fo ha and fo layou aspec aio is adjusing he design o available on-chip measuemen equipmen and inegaion of he es chip on he muli-pojec-wafe available aea I should be emphasized ha, in ode o have possibiliy of exenal calibaion, an addiional cicui is added The cicui is composed of he hee muliplexes conolled by signal ese_n which deemines whehe he calibaion is inenal o exenal Also, shif egise is implemened fo wiing hee conol bis via wo exenal signals 74

10 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), µm a) 490µm b) Figue 5: File a) and b) paamees in compensaed (geen), simulaed (ed) and non-compensaed case (puple) Figue 4: Inegaed design- layou view The Figue 5 shows he measuemen esuls of he cicui using inenal calibaion pocedue Measuemens ae pefomed unde nominal condiions - a he oom empeaue and nominal supply volage As i can be seen fom he figue, he compensaed file ansfe chaaceisic maches well wih he simulaed one - a he cuoff fequency he diffeence is 06 db Also, uncompensaed file chaaceisic is shown In his case, conol bis have andom values The diffeence beween simulaed and non-compensaed case a cu-off fequency is unaccepable db Figue 6 and Figue 7 pesen he phoo of he I die and he measuemen se-up using he on-wafe pobes Figue 6: Die phoo 5 onclusion This pape poposes one way of fully inegaed onchip calibaion of -capacio pocess induced vaiaion, uilizing moe sable MO capacio as efeence The es cicui is designed and veified using sandad 0 nm MO pocess The concep is applied o lowpass file design and is veified hough simulaions and measuemens Afe he calibaion is applied, capaciance vaiaion is loweed fom 5% o 8% Moeove, opimizaion of RF swiches is poposed 75

11 B Milinković e al; Infomacije Midem, Vol 45, No 4 (05), Figue 7: Die wih pobes ih adoped opimizaion, he swiches incease file inseion loss no moe han 06 db in on sae, and inoduce addiional capacio eo below % when hey ae all off The same mehod can be used fo compensaing he pocess vaiaion in any ohe cicui ype and in any ohe MO echnology pocess 6 Acknowledgmens 4 IEEE d 8054a-007 (007) Amendmen o : ieless Medium Access onol (MA) and Physical Laye (PHY) pecificaions fo Low-Rae ieless Pesonal Aea Newoks (LR- PANs) 5 R Rhea (994) HF File Design and ompue imulaion, Noble Publishing opoaion, Geogia- UA 6 B Razavi (00) Design of Analog MO Inegaed icuis, McGaw-Hill, New Yok 7 B Min (008) ige/mo Millimee-ave Inegaed icuis and afe-cale Packaging fo Phased Aay ysems, PhD hesis, The Univesiy of Michigan 8 A Niknejad (007) Elecomagneics fo High- peed Analog and Digial ommunicaion icui, ambidge Univesiy Pess, New Yok 9 M chneide, Galup-Monoo (00) MO Analog Design Using All-Region MOFET Modeling, ambidge Univesiy Pess, New Yok 0 J Bhaske, R hadha (009) aic Timing Analysis fo Nanomee Designs- A Pacical Appoach, pinge, New Yok D Hais, Hais (0) Digial Design and ompue Achiecue, Elsevie, alham, Massachuses Aived: Acceped: 05 The auhos would like o hank Faculy of Technical cience, Depamen fo Powe, Eleconic and Telecommunicaion Engineeing in Novi ad, ebia, fo poviding measuemen faciliies The design is pa of he ENEIVER pojec- wwwsenseivecom founded by Euopean Union s evenh Famewok Pogamme 7 Refeences M Pase, M Kayal (006) Mehodology fo he Digial alibaion of Analog icuis and ysems, pinge, Nehelands - Lee (0) On-chip Benchmaking and alibaion wihou Exenal Refeences, PhD hesis, EE Depamen, Univesiy of alifonia, Bekeley I Milosavljević, D Gujić, Đ imić, J Popović- Božović (04) Esimaion and compensaion of pocess-induced vaiaions in capacios fo impoved eliabiliy in inegaed cicuis, Analog Inegaed icuis and ignal Pocessing, vol 8, no, pp