THE ARCHITECTURE OF THE BROADBAND AMPLIFIERS WITHOUT CLASSICAL STAGES WITH A COMMON BASE AND A COMMON EMITTER

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1 VOL. 0, NO. 8, OCTOBE 205 ISSN Asan esearch Publshng Network (APN. All rghts reserved. THE ACHITECTUE OF THE BOADBAND AMPLIFIES WITHOUT CLASSICAL STAGES WITH A COMMON BASE AND A COMMON EMITTE Nkolay Nkolaevch Prokopenko, Nkolay Vladmrovch Butyrlagn and Ilya Vktorovch Pakhomov Don State Techncal Unversty, ostov-on-don, Gagarn, ostov-on-don, ostov egon, ussa E-Mal: prokopenko@sssu.ru ABSTACT Ths artcle consders a new desgn method of broadband amplfers (BrA for automaton and control systems wth hgher voltage transfer rato (Gan = 8 58 db. The feature of the proposed archtectures of BrA les n ther mplementaton on the bass of emtter followers and current mrrors n the elemental bass of bpolar n-p-n transstors, for example, desgnated for the technologcal process SGB25VD and n the absence of classcal stages wth a common emtter or a common base. The results of computer smulatons n the Cadence and Orcad envronments are submtted. eywords: broadband amplfer, current mrror, emtter follower, transfer rato. INTODUCTION The use of CMOS transstors s a man vector of the development of ntegrated crcuts for sensor systems and automatc devces. At equal geometry rules the operatng band of bpolar transstor amplfers, among whch the complementary-symmetry crcuts [-2] occupy a specal place, occurs hgher than on the feld-effect devces. There are other advantages of BJTs [-4]. In addton, there are "nches" for the effectve applcaton of the crcuts on actve elements of BJT [5]. The use of conventonal actve loads n the analog ntegrated crcuts wth the technology SGB25VD [] s lmted by the capactes of CMOS transstors as p-n-p bpolar transstors are not realzed n ths technology. The concepts of nherent compensaton and cancellaton of mpedances, suggested n [], allow developng analog functonal unts (operatonal amplfers, comparators, voltage regulators, etc. wthout applcaton of FETs and p- n-p bpolar transstors. Ths artcle consders a new desgn method of broadband amplfers (BrA [], based on the fundamental propertes of current and voltage followers [6-8]. Ther man dfference les n the absence of classc stages wth a common emtter or a common base. THE ACHITECTUE OF THE BOADBAND AMPLIFIES ON THE BASIS OF A DIFFEENTIAL EMITTE FOLLOWE The archtecture of BrA (Fgure-, suggested n [2], allows obtanng the output voltage at asymmetrcal load startng whch depends on the voltage (u n. on the base of both transstors VT and VT2 of nput emtter followers,.e. realzng the functons of the dfferental amplfer u n 0( un. un. 2, where 0 - s the voltage gan of BrA. In the statc mode the emtter current values of transstors VT and VT2 are set by the current sources I and I 2 and they are also due to the choce of resstance values of resstors and. If the voltage u n. s appled to the nput In. t causes an ncrease of current through the resstor : un. u un. ( 0, ( where 0=u out u n. - s the voltage gan of BrA. Fgure-. The archtecture of BrA on the base of the emtter followers and the current mrror (CM. Meanwhle, the current ncrement s transmtted through the current mrror CM nto the resstor 2 and causes an ncrease of voltage on ths resstor. Therefore, the voltage u 2 on the current source I 2, stablzng the current flow, decreases. It leads to a decrease of the voltage on the output u out of the broadband amplfer and on the current source I, ths s due to the 8085

2 VOL. 0, NO. 8, OCTOBE 205 ISSN Asan esearch Publshng Network (APN. All rghts reserved. fact that at the transfer rato BA= of the buffer amplfer (on the transstor VT the followng equaton s satsfed: uout u2 u. (2 Thus, the voltage phase u out on the output of the BrA s opposed to the nput voltage phase u n and the amplfcaton factor s equal to: 2. Gan, ( 2. the current mrror (CM and the current flow through the resstor. Therefore, n ths mode the output voltage of BrA and the nput voltage u n.2 have the same phase. The computer smulaton of BrA, carred out on transstors of FSUE and DE "Pulsar", shows that 0 of the stage (Fgure- can be more than 00 db f t comprses an deal current mrror ( 2.= and an deal buffer amplfer. It s enough n most cases of the use n automatc devces. Thus, wth the chosen parameters of elements ( 00 Ohm, I I 2 ma, BA= the crcut of Fgure- provdes the amplfcaton of the sgnal wth Gan 80 db, f Fgure-2. CM. where 2. s the current transfer rato of the current mrror (CM. If =, and the coeffcent 2.= , then at hgh-resstance load ( load= the coeffcent 0 wll be: 0. (4 2. It means that the crcut of Fgure- provdes the amplfcaton, whch s bgger than one. If the load resstance load, we ll have the followng: 2. 0, (5 2. where β load - s the equvalent 2 resstance n the output crcut of the current mrror (CM; β s the current gan of the base of transstor VT of the output of emtter follower (BA. In ths case, to get the maxmum value of 0.max. t s necessary to choose takng nto consderaton the followng equaton: Fgure-2. The dependence of the cut-off amplfcaton factor of BrA (Fgure- on the transfer rato of current mrror 2.= CM f BA=. In practcal crcuts of BrA wth a standard current mrror the coeffcent 0 0 (60 db. It s 4 5 possble to get 0 0 0, f we desgn the current mrror (CM n a specal way. For example, t can be smlar to Vlson s scheme or t may have more senstve buffer amplfers provdng BA. The lmt values of 0.max when 2. CM are defned by the technologcal dsperson of emtter resstors (Fgure (6 If the nput voltage u n.2 s appled through the second nput of BrA (In.2, t nduces the common-mode voltage change on the base of transstor VT. The values of the output voltage u out and the voltage u also change. Consequently, the current flow through the resstor decreases, ths causes a decrease of the output current of Fgure-. The nfluence of the dsperson of the resstors and on the cut-off amplfcaton factor of BrA (Fgure

3 VOL. 0, NO. 8, OCTOBE 205 ISSN Asan esearch Publshng Network (APN. All rghts reserved. However, the numercal values of 0 reach 0 70 db, f the relatve error of resstors and s not hgher than / 0%. Fgure-4 shows the crcut of BrA (Fgure- n the Cadence computer smulaton carred out on SGe prototypes of ntegrated transstors. Fgure-5 llustrates the dependence of the voltage gan of BrA on the frequency. Fgure-6. Dfferental stage desgned on the bass of current and voltage followers []. If postve voltage ncrement u n s appled to the nput of DS (Fgure-6, t causes an ncrease of emtter and collector currents of the transstor VT: Fgure-4. The crcut of BrA n the Cadence computer smulaton. Accordng to the graphs, shown n (Fgure-5, the voltage gan of BrA (Fgure-4 reaches 2 db. Fgure-5. The dependence of the voltage gan of BrA (Fgure-4 on the frequency. THE DIFFEENTIAL STAGES BASED ON NPN SIGE TANSISTOS Accordng to the archtecture of Fgure- the crcuts of dfferent dfferental stages are realzed on the bass of n-p-n SGe transstors (Fgure-6 []. u u u ( n A n 0 e c, (7 re where r e - are resstances of emtter juncton of the transstor VT; - are resstance values of and ; s a voltage transfer rato from nput nto the crcut of emtter of the transstor VT4 (. The numercal values of 0 ( are defned by the dfference between resstances of and. They also depend on the rate of accuracy of the current mrror (CM and the buffer amplfer (BA whch s defned by the dfference of ther transfer ratos from one ( I2., BA. The ncrement e comes to the nput of the current mrror (CM, the output current of whch s out e. Then the ncrement e goes to the resstor, emtter and collector of the transstor VT2: u n e2 e ( 0 c2. (8 That s why the alternatng current wll flow through the resstor and t wll generate the output voltage u out: un 2e 2( 0, (9 8087

4 VOL. 0, NO. 8, OCTOBE 205 ISSN Asan esearch Publshng Network (APN. All rghts reserved. u out 2( 0. (0 Consequently, the voltage gan of DS (Fgure-6 wll be: Gan 2( 0. ( For practcal crcuts , ths ncreases the amplfcaton factor consderably. These conclusons are proved by the results of computer smulaton of the crcuts (Fgure-7 on the prototypes of the transstors produced by FSUE and DE "Pulsar". Fgure-8. The crcut of the operatonal amplfer based on the current mrror (CM and emtter followers. Fgure-9 shows the crcut of OA (Fgure-8 n the Cadence computer smulaton on SGe ntegrated transstors SG25H and frequency dependence of ts voltage gan. a b Fgure-7. The crcut of DS (Fgure-6 n the PSpce envronment of computer smulaton (a and frequency dependence of ts voltage gan (b. SIGE OPEATIONAL AMPLIFIES The operatonal amplfers (ОА are realzed on the bass of dfferental stages of Fgure-6 whch allow ntroducng common negatve feedback on drect current (Fgure-8. a 8088

5 VOL. 0, NO. 8, OCTOBE 205 ISSN Asan esearch Publshng Network (APN. All rghts reserved. EFEENCES b Fgure-9. The crcut of OA n the Cadence computer smulaton on SGe ntegrated transstors (a and frequency dependence of ts voltage gan (b. The analyss of the graphs of Fgure-9 shows that, at constant current the voltage gan of the operatonal amplfer s n the range of db. CONCLUSIONS The consdered archtectures of amplfers extend the dea, exstng among engneers, about desgn methods of analog ntegrated crcuts, realzed on SGB25VD, SG25H technologes wthout p-n-p transstors. The lmt values of amplfcaton factors of dfferental stages of the consdered category are defned by the dfference between resstances of emtter resstors and whch must not have dsperson more than 0%; by ther absolute value and also by the correcton of the current rato of current mrror CM from unty, by the nput resstance of buffer amplfer and ts voltage transfer rato (К ВА. The most effectve feld of applcaton of the consdered broadband amplfers, dfferental stages and operatonal amplfers made on ther bass s low voltage technologcal processes, where p-n-p transstors are not realzed or they are very neffectve. ACNOWLEDGEMENT Ths artcle was prepared under the project / of the state assgnment of Mnstry of Educaton and Scence of the ussan Federaton for [] Prokopenko N. N., Serebryakov A. I., Budyakov P. S. Archtecture of the mcrowave dfferental operatng amplfers wth paraphrase output// Internatonal Conference on Sgnals and Electronc Systems (ICSES: conference proceedngs. IEEE Catalog Number: CFP057D-USB (Glwce, Poland, 7-0 September, 200 С WOS: [2] Dostal J. 99. Operatonal Amplfers, Second Edton, Butterworth-Henemann. p. 87. [] O. E. Matta, H. lmach and S. Bamp esstorless BJT bas and curvature compensaton crcut at.4nw for CMOS bandgap voltage references. Electroncs Letters. 50(2: [4] F. For, P. S. Crovett and V. Pozzolo Predcton of F nterference n operatonal amplfers by a new analytcal model. Electromagnetc Compatblty. EMC, IEEE Internatonal Symposum on electromagnetc compatblty, Montreal, Canada. pp [5] A. Gupta, A. Bhansal, S. Bhargava, S. Jan Confguraton of Operatonal Amplfer Usng CMOS. [Onlne]. Avalable: comp/4.pdf. [Accessed: 09-Sep-204]. [6] N. N. Prokopenko, N. V. ovbasyuk. Shakhty Archtecture and crcut desgn of analog crcuts wth nherent compensaton and cancellaton of mpedances: Monograph /: SSUES [7] N. N. Prokopenko, P. S. Budyakov, A. I. Serebryakov. 20. Dfferental amplfer. U Patent [8] N. N. Prokopenko, A. I. Serebryakov, N. N. Nkulchev. 20. Dfferental amplfer wth hgh voltage gan. U Patent