TE 9 FEQUENY ESONSE hapte Outline 9. w Fequency epne the S and E pliie 9. ntenal apacitive Eect and the ih Fequency del 9. ih Fequency epne the S and E pliie 9.4 Tl the nalyi the ih Fequency epne pliie 9.5 le k at the ih Fequency epne 9.6 ih Fequency epne the and acde pliie NTUEE Electnic.. u 9
Fequency epne apliie idband: The equency ane inteet apliie ae capacit can be teated a ht cicuit and all capacit can be teated a pen cicuit ain i cntant and can be btained by all nal analyi w equency band: ain dp at equencie lwe than ae capacit can n lne be teated a ht cicuit The ain ll i ainly due t cuplin and by pa capacit ih equency band: ain dp at equencie hihe than Sall capacit can n lne teated a pen cicuit The ain ll i ainly due t paaitic capacitance the OSFET and JT NTUEE Electnic.. u 9
9. w Fequency epne the S and E pliie The S apliie Sall nal analyi: NTUEE Electnic.. u 9 S d d S d
eteinin the lwe d equency uplin and by pa capacit eult in a hih pa equency epne with thee ple the ple ae uiciently epaated de plt can be ued t evaluate the epne iplicity The lwe d equency i the hihet equency ple i typically the hihet equency ple due t all eitance the ple ae lcated clely The lwe d equency ha t be evaluated by the tane unctin which i e cplicated eteinin the ple equency by inpectin educe t ze nide each capacit epaately teat the the capacit a ht cicuit Find the ttal eitance between the teinal Selectin value cuplin and by pa capacit Thee capacit ae typically equied dicete apliie den S i it deteined t atiy needed and ae chen uch that ple ae 5 t 0 tie lwe than NTUEE Electnic.. u 9 4
The E apliie Sall nal analyi nidein the eect each capacit epaately nidein nly : NTUEE Electnic.. u 9 5
nidein nly E : nidein nly : NTUEE Electnic.. u 9 6 e E e E e b E e b
eteinin the lwe d equency uplin and by pa capacit eult in a hih pa equency epne with thee ple The lwe d equency i iply the hihet equency ple i the ple ae uiciently epaated The hihet equency ple i typically due t the all eitance E n appxiatin the lwe d equency i iven by Selectin value the cuplin and by pa capacit Thee capacit ae typically equied dicete apliie den E i it deteined t atiy needed and ae chen uch that ple ae 5 t 0 tie lwe than NTUEE Electnic.. u 9 7 E E
9. ntenal apacitive Eect and the ih Fequency del The OSFET device Thee ae baically tw type intenal capacitance in the OSFET ate capacitance eect: the ate electde a paallel plate capacit with ate xide in the iddle Junctin capacitance eect: the ucebdy and dainbdy ae pn junctin at evee bia The ate capacitive eect OSFET in tide ein: W OSFET in atuatin ein: W OSFET in cut ein: Ovelap capacitance: W v x v x v x v v v b W x The junctin capacitance Junctin capacitance include cpnent the btt ide and the ide wall The ipliied expein ae iven by b b0 S 0 db db0 0 NTUEE Electnic.. u 9 8
The hih equency OSFET del b b db n x v W W x x W b0 S db0 W v v x n x W Sipliied hih equency OSFET del Suce and bdy teinal ae hted play an iptant le in the apliie equency epne db i nelected t ipliy the analyi NTUEE Electnic.. u 9 9
The unity ain equency T The equency at which the cuent ain bece unity typically ued a an indicat t evaluate the hih equency capability Salle paaitic capacitance and ae deiable hihe unity ain equency i T i The unity ain equency can al be expeed a T T W nx W n x O n 4 O n W x The unity ain equency i tnly inluenced by the channel lenth ihe unity ain equency can be achieved a iven OSFET by inceain the bia cuent the vedive vltae NTUEE Electnic.. u 9 0
The JT evice ih equency hybid del: The bae chain diuin capacitance de : The bae eitte junctin capacitance je : The cllect bae junctin capacitance : The cut unity ain equency: NTUEE Electnic.. u 9 T F F de j0 je c 0 0 T T e b c e b b c h h 0
9. ih Fequency epne the S and E pliie The cn uce apliie idband ain: Fequency epne: The cn uce apliie ha ne ze and tw ple at hihe equencie The apliie ain all at equencie beynd idband The apliie bandwidth i deined by the d equency which i typically evaluated by the dinant ple the lwet equency ple in the tane unctin NTUEE Electnic.. u 9
Sipliied analyi technique uin the ain i nealy cntant Find the equivalent capacitance at the input with identical [ ] eq eq ille eect Nelect the all cuent at the utput { [ ]} [ ] The dinant ple i nally deteined by eq The equency epne the cn uce apliie i appxiated by a ST NTUEE Electnic.. u 9
The cn eitte apliie Sipliied analyi equency epne ille eect: eplacin with eq The epne i appxiated by a ST {[ ][ ]} NTUEE Electnic.. u 9 4
9.4 Ueul Tl the nalyi the ih Fequency epne pliie eteinin the uppe d equency eneal tane unctin the apliie The uppe d equency dinant ple epne One the ple i uch lwe equency than any the the ple and ze inant ple: the lwet equency ple i at leat 4 away the neaet ple ze NTUEE Electnic.. u 9 5 n F 4 4 j F F
Open cicuit tie cntant ethd t evaluate apliie bandwidth eneal tane unctin the apliie Open cicuit tie cntant exact lutin: inant ple appxiatin: ille Thee technique t eplace the bidin capacitance The equivalent input and utput ipedance ae: NTUEE Electnic.. u 9 6 n b n i i i b i i i n b b n n n b b b a a a F K K K
Tie cntant ethd* technique ued t deteine the ceicient the tane unctin the cicuit F eteinin b : b n b b 0 0 0 a a Set all independent uce ze 0 ii: the equivalent eitance in paallel with i by teatin the the capacit a pen cicuit eteinin b : b 0 0 0 Set all independent uce ze j ii: the equivalent eitance in paallel with i by teatin j ht and the the capacit pen a b n n NTUEE Electnic.. u 9 7
9.5 le k at the ih Fequency epne Exact analyi by tane unctin Tane unctin the apliie: Step : deine ndal vltae Step : ind banch cuent Step : K equatin Step 4: tane unctin by lvin the linea equatin le and ze: NTUEE Electnic.. u 9 8 ] [ } ] {[ ] [ } ] {[ ] [ ] [ ] [ ] [
nalyi by uin pen cicuit tie cntant Open cicuit tie cntant: NTUEE Electnic.. u 9 9 ] [ ] [
nalyi by uin ille Thee idin capacitance i eplaced by and Tane unctin and : Open cicuit tie cntant analyi baed n ille equivalent cicuit: NTUEE Electnic.. u 9 0 K K K K in ] [ in in in ] [ ] [
S apliie with a all uce eitance The cae whee uce eitance i ze 0 The tane unctin the apliie: [ idband ain: ] The tane unctin ha ne ple and ne ze [ ] idband ain and ze ae vitually unchaned The lwet equency ple n lne exit ain bandwidth pduct: ain ll beynd 0 ddecade The ain bece 0 d at t : t NTUEE Electnic.. u 9
9.6 ih Fequency epne the and acde pliie ih equency epne the apliie The equency epne by nelectin : idband ain: le: [ The uppe d equency Typically hihe than the S apliie The equency epne includin : Open cicuit tie cntant ethd in [ in ] ] NTUEE Electnic.. u 9
ih equency epne the cacde apliie Open cicuit tie cntant ethd: apacitance ee a eitance apacitance ee a eitance apacitance db + ee a eitance d apacitance + ee a eitance d d Eective tie cntant in [ ] d The uppe d equency: n the cae a lae : [ d d] db d The it te dinate i the ille ultiplie i lae typically with lae d and all t the de i needed extended bandwidth The idband ain dp a the value deceae tade exit between ain and bandwidth { [ d] d db } NTUEE Electnic.. u 9
n the cae a all : The it te bece neliible and the thid te dinate lae t the de 0 can be ued t bt the apliie ain n the cae ze : t Suay S and cacde apliie NTUEE Electnic.. u 9 4
ih equency epne the bipla cacde apliie The iila analyi technique can be applied bipla cacde apliie. NTUEE Electnic.. u 9 5
9.7 ih Fequency epne the Suce and Eitte Fllwe The uce llwe: w equency idband ain and utput eitance: ih equency chaacteitic: ih equency ze: Output bece 0 at = = ih equency ze: = T tanit unity ain equency The d equency : NTUEE Electnic.. u 9 6
The eitte llwe: w equency idband ain and utput eitance: e [ e ] ih equency chaacteitic: ih equency ze: Output bece 0 at = = e ih equency ze: = e T tanit unity ain equency The d equency : [ ] e NTUEE Electnic.. u 9 7
9.8 ih Fequency epne ieential pliie eitively aded OS ieential pliie: ieential de peatin: Ue dieential hal cicuit analyi dentical t the cae cn uce apliie an be appxiated by a dinant ple yte n de peatin: Ue cn de hal cicuit analyi The capacitance SS i niicant SS eult in a ze at lwe equency Othe capacitance hih equency ple and ze c c SS SS SS SS SS SS SS SS SS NTUEE Electnic.. u 9 8
n de ejectin ati : The equency dependence can be evaluated deceae at hihe equencie due t the ple d and the ze c NTUEE Electnic.. u 9 9
ctive aded OS ieential pliie: ieential de peatin: Equivalent capacitance: Tancnductance : The ple and ze ae at vey hih equencie in ple and ze nea unity ain equency NTUEE Electnic.. u 9 0 x db db db db 4 4 4 T T 4 4 4 4 id id id d d id id d id
The tane unctin the apliie: The dinant ple i typically id id id n de peatin: y takin SS int accunt the id band cn de ain: c SS SS SS SS SS 4 SS 4 ntibute t a ze at lwe equency n de ejectin ati : deceae due t the dinant ple d and the ze c NTUEE Electnic.. u 9