Microelectronic Circuits II. Ch 8 : Frequency Response

Transcription

1 Micrelectrnic ircuit II h 8 : Frequency ene 8. -Frequency ene f S & E Amlifier NU EE 8.-

2 Intrductin - ain i cntant indeendent f the frequency f the inut nal à infinite andidth à Nt true, - midand : ain remain almt cntant ver a ide frequency rane culin & ya caacitr à hrt, internal caacitance à en - ler freq. and : culin & ya caacitr n lner have l imedance, f : ler end f mid-frequency, reactance /j - hih freq. and : internal caacitance f tranitr n lner have hih imedance, f H : uer end f mid-frequency, reactance /j - Amlifier andidth f H f - Extenin f andidth i.e., increae f H à urce deeneratin reitance NU EE Manitude f the ain f a dicrete JT r MOS amlifier v. frequency 8.-

3 Aendix E : ST Sinle Time ntant circuit - inle-time-cntant ST circuit : ne reactive cmnent r & ne reitance - An ST circuit : time cntant t / r - Evaluatin the time cntant reduce the excitatin t zer : vltae urce à hrt, current urce à en find equivalent reitance eq een y the ne reactive cmnent : eq 4 [ 3 ] 3 time cntant i either / eq r eq t { 4 [ 3 ]} NU EE 8.-3

4 laificatin f ST circuit - T caterie : l-a & hih-a H tye - l-a circuit a dc i.e., nal / zer freq. and attenuate hih freq. / zer tranmiin at - At 0, caacitr à en circuit /j, inductr à hrt circuit j 0 - At, caacitr à hrt circuit /j 0, inductr à en circuit j l-a tye hih-a tye NU EE 8.-4

5 -a circuit manitude rene hae rene - ST l-a circuit tranfer functin T T j j 0 K: ain at 0, 0 /t t :time cntant - Manitude rene, hae rene K - j f - tan Manitude axi d : 0l Tj/K - freq. axi rad/ec:larithmic cale/ 0 - l-frequency aymtte Tj ~ ~0d - / 0 >> : if dule, Tj i halved à le : -6d/ctave, -0d/decade - t traiht-line aymtte f the manitude rene curve meet at the rner freq. r reak freq. 0-0, ain dr y a factr f relative t the dc ain à crner freq. 3-d frequency NU EE 8.-5 T K 0 T j» K T j0 K K 0

6 Hih-a circuit manitude rene hae rene - ST hih-a circuit tranfer functin K K T T j 0 - j 0 K: ain at, 0 /t t :time cntant - Manitude rene, hae rene K - T j f tan Manitude axi d : 0l Tj/K - freq. axi rad/ec:larithmic cale/ 0 - hih-frequency aymtte Tj ~ ~0d - / 0 << : if dule, Tj i duled à le : 6d/ctave, 0d/decade T j» K 0 - t traiht-line aymtte f the manitude rene curve meet at the rner freq. r reak freq. 0-0, ain dr y a factr f relative t the ain at hih frequency à crner freq. 3-d frequency T j0 K NU EE 8.-6

7 Frequency rene f ST netrk NU EE 8.-7

8 Small-nal equivalent circuit mdel MOSFET 등가회로 모델 T mdel aturatin mde / W id kn GS - v tn NU EE 8.-8

9 -Frequency rene f S amlifier frequency indeendent analyi -,,: culin caacitr - S mf: ya caacitr - Effect f caacitance n ain / - at midand frequencie,,, S mf àneliily mall imedance, and aume erfect hrt circuit à midand ain r G A M º - m D G - at l frequencie, reactance /j f,, S mf increae & amlifier ain decreae three frequency and - midand : ueful and f amlifier - l-frequency and :,, S - hih-frequency and :, d NU EE 8.-9

10 -frequency rene f S amlifier T mdel Determinin / at l frequency - current urce I : en - vltae urce DD : hrt - direct mall-nal analyi N r - Determinin, I d, I, & G G G G G G ulin caacitr intrduce a hih-a ST rene / a reak frequency Drain current I d frm amlifier inut I d m m NU EE m S S 8.-0 m S S intrduce a frequencydeendent factr& ST hih-a tye / a reak frequency

11 NU EE 8.- [ ] [ ] D m G G M M D m G G d d A A I I frequency rene f S amlifier D d D I I - O frm I d y uin current-divider rule D d D D I I - intrduce a 3 rd hih-a factr / a 3 rd reak frequency at Overall l-frequency tranfer functin f S amlifier 3 D A M : Midand ain ith,, S actin a erfect hrt circuit

12 -frequency rene f S amlifier Determinin ler 3-d frequency, f - er 3-d frequency, f frequency at hich / dr t A M / - If the reak frequency,, & 3 are ufficiently earated, their effect aear ditinct. - At each reak frequency, ain le increae y 0d/decade - f, f & f 3 : l-frequency le - If the hihet-frequency le, f, i earated frm the nearet le, f 3 y at leat a factr f 4 t ctave : - The hihet le, f ~ ecaue interact ith / m, hich i l Determinin the le frequencie y inectin. educe t zer. nider each caacitr earately; that i, aume that the ther t caacitr are actin a erfect hrt circuit 3. Fr each caacitr, find the ttal reitance een eteen it terminal. Thi i the reitance that determine the time cntant aciated ith thi caacitr NU EE 8.- f

13 Small-nal equivalent circuit mdel JT 등가회로 모델 T mdel NU EE 8.-3

14 -frequency rene f E amlifier frequency indeendent analyi -,, E mf: hrt circuit -, m F rane: en circuit - A M cntant in the midand A M º r - r r three frequency and - midand : ueful and f amlifier - l-frequency and :,, E - hih-frequency and :, m m andidth r 3-d andidth W f H f ~ f H hen f << f H ain-andidth rduct G A M W : trade-ff ain fr andidth NU EE 8.-4

15 -frequency rene f E amlifier T mdel Simle circuit fr Frequency rene - current urce I : en - vltae urce : hrt - inre & m : en - nelect r x ince r x << r Analyi f the l-frequency rene f the E amlifier - cnider the effect f the three caacitr, E & ne at a time NU EE 8.-5

16 -frequency rene f E amlifier 모델 Effect f ith E & hrt-circuited r r r - r m é ê ê ê ê ë - [ intrduce a ST hih-a tye / a reak frequency NU EE A M [ r ] i the reitance een eteen the terminal f hen v 0 m r ù ú ú ú ] ú û [ r ]

17 NU EE frequency rene f E amlifier ú û ù ê ë é / e E e E e E e E e r r r r I r I Effect f E ith & hrt-circuited & utilizin Thevenin therem [r e /] i the reitance een eteen the t terminal f E hen v 0 E intrduce a ST hih-a tye / a reak frequency T 모델

18 NU EE frequency rene f E amlifier 3 3 M A - ú ú ú ú û ù ê ê ê ê ë é - - m m r r r r Effect f ith E & hrt-circuited i the reitance een eteen the terminal f hen v 0 intrduce a ST hih-a tye / a reak frequency 3 모델

19 NU EE frequency rene f E amlifier Overall l-frequency tranfer functin f E amlifier - 3 M A 3-d frequency f i determined y the hihet f the three reak frequencie the reak frequency i caued y the ya caacitr E, that i f ~ f