PEATINAL AMPLIFIES Why do we study them at ths pont???. pamps are ery useful electronc components. We hae already the tools to analyze practcal crcuts usng pamps 3. The lnear models for pamps nclude dependent sources TYPICAL DEICE USING P-AMPS
LM34 DIP LMC694 MAX440 P-AMP ASSEMBLED N PINTED CICUIT BAD APEX PA03 DIMENSINAL DIAGAM LM 34 PIN UT F LM34
CICUIT SYMBL F AN P-AMP SHWING PWE SUPPLIES LINEA MDEL INPUT ESISTANCE UTPUT ESISTANCE TYPICAL ALUES : A :0 0 5 5 : Ω Ω 0 0 50Ω 7 Ω GAIN
CICUIT WITH PEATINAL AMPLIFIE P-AMP LAD DIING CICUIT
TANSFE PLTS F SME CMECIAL P-AMPS LINEA EGIN SATUATIN EGIN IDENTIFY SATUATIN EGINS P-AMP IN SATUATIN
CICUIT AND MDEL F UNITY GAIN BUFFE WHY UNIT GAIN BUFFE? PEFMANCE F EAL P-AMPS p-amp BUFFE GAIN LM34 0.99999 LMC649 0.9998 MAX440 0.99995 KL : s KL : I - out I A n I A n CNTLLING AIABLE: SLING BUFFE GAIN out s A A out S n 0 0 I
THE IDEAL P-AMP IDEAL 0,, A 0 A ( A
THE UNITY GAIN BUFFE IDEAL P-AMP ASSUMPTIN s UT UT S UT UT S USING LINEA (NN-IDEAL P-AMP MDEL WE BTAINED out s A PEFMANCE F EAL P-AMPS p-amp BUFFE GAIN LM34 0.99999 LMC649 0.9998 MAX440 0.99995 IDEAL P-AMP ASSUMPTIN YIELDS EXCELLENT APPXIMATIN!
WHY USE THE LTAGE FLLWE UNITY GAIN BUFFE? s S THE LTAGE FLLWE ACTS AS BUFFE AMPLIFIE THE LTAGE FLLWE ISLATES NE CICUIT FM ANTHE ESPECIALLY USEFUL IF THE SUCE HAS EY LITTLE PWE CNNECTIN WITHUT BUFFE CNNECTIN WITH BUFFE S THE SUCE SUPPLIES PWE THE SUCE SUPPLIES N PWE
LEANING EXAMPLE DETEMINE APPLY KCL @ - s 0 out 0 0 THE GAIN 0 G out s G out s 0 0 A o 0 0 F CMPAISN, NEXT WE EXAMINE THE SAME CICUIT WITHUT THE ASSUMPTIN F IDEAL P-AMP
EPLACING P-AMPS BY THEI LINEA MDEL WE USE THIS EXAMPLE T DEELP A PCEDUE T DETEMINE P-AMP CICUITS USING THE LINEA MDELS
. Identfy p Amp nodes 3. Draw components of lnear pamp (on crcut of step o o A (. edraw the crcut cuttng out the p Amp 4. edraw as needed o
INETING AMPLIFIE: ANALYSIS F NN IDEAL CASE USE LINEA ALGEBA NDE ANALYSIS CNTLLING AIABLE IN TEMS F NDE LTAGES TYPICAL P - AMP: 8 0 Ω, 0Ω A 0 5, kω, 5kΩ 4.9996994 A 5. 000 S S
SUMMAY CMPAISN: IDEAL P-AMP AND NN-IDEAL CASE 0 0 0 A 0 KCL @ INETING TEMINAL 0 S 0 0 s GAIN F NN-IDEAL CASE NN-IDEAL CASE EPLACE P-AMP BY LINEA MDEL SLE THE ESULTING CICUIT WITH DEPENDENT SUCES THE IDEAL P-AMP ASSUMPTIN PIDES EXCELLENT APPXIMATIN. (UNLESS FCED THEWISE WE WILL ALWAYS USE IT!
THINK NDES! LEANING EXAMPLE: DIFFEENTIAL AMPLIFIE UTPUT CUENT IS NT KNWN THE P-AMP IS DEFINED BY ITS 3 NDES. HENCE IT NEEDS 3 EQUATINS KCL AT _ AND YIELD TW EQUATINS (INFINITE INPUT ESISTANCE IMPLIES THAT -, AE KNWN DN T USE KCL AT UTPUT NDE. GET THID EQUATIN FM INFINITE GAIN ASSUMPTIN ( -
LEANING EXAMPLE: DIFFEENTIAL AMPLIFIE NDES @ INETING TEMINAL NDES @ NN INETING TEMINAL IDEAL P-AMP CNDITINS 4 3 4 4 3 4 0 (, 3 4
LEANING EXAMPLE: USE IDEAL P-AMP FIND o m m m o m 6 NDE EQUATINS IDEAL P-AMP FINISH WITH INPUT NDE EQUATINS USE INFINTE GAIN ASSUMPTIN m m USE EMAINING NDE EQUATINS @ m @ 0 o : 0 : G o m G NLY UNKWNS AE UTPUT NDE LTAGES SLE F EQUIED AIABLE o 0 o 0 0
LEANING EXTENSIN FIND I. ASSUME IDEAL P - AMP A 0 KCL@ o : 0 k k o 84 o I 4mA 0 k 8.
LEANING EXTENSIN NNINETING AMPLIFIE - IDEAL P-AMP 0 _ o 0 SET LTAGE INFINITE GAIN ASSUMPTIN nerse oltage dder 0 0 INFINITE INPUT ESISTANCE
FIND GAIN AND INPUT ESISTANCE - NN IDEAL P-AMP CMPLETE EQUIALENT F MESH ANALYSIS A ( DETEMINE EQUIALENT CICUIT USING LINEA MDEL F P-AMP NW E-DAW CICUIT T ENHANCE CLAITY. THEE AE NLY TW LPS MESH MESH CNTLLNG AIABLE IN TEMS F LP CUENTS (
INPUT ESISTANCE n GAIN G MESH MESH CNTLLNG AIABLE IN TEMS F LP CUENTS MATHEMATICAL MDEL ( EPLACE AND PUT IN MATIX FM 0 ( ( A 0 ( ( A THE FMAL SLUTIN ( ( ( A ( ( ( A Adj 0 ( ( ( A THE SLUTINS ( A A??? ( ( ( ( A A A n G
A SEMI-IDEAL P-AMP MDEL Ths s an ntermedate model, more accurate than the deal op-amp model but smpler than the lnear model used so far, 0, A A 0!! e n eplacement Equaton A A ( e Non-nertng amplfer and sem-deal model A S ; β A β S! (as before actual gan-deal gan GE A ( (replaces deal gan S A β
Sample Problem S - S 0 Set oltages? S Use nfnte gan assumpton S Use nfnte nput resstance assumpton and apply KCL to nertng nput S o o S 0 S Fnd the expresson for o. Indcate where and how you are usng the Ideal pamp assumptons
Sample Problem DAW THE LINEA EQUIALENT CICUIT AND WITE THE LP EQUATINS 4. edraw f necessary o S A ( S - A( - -. Locate nodes. Erase p-amp 3. Place lnear model TW LPS. NE CUENT SUCE. USE MESHES MESH s MESH ( S ( A( _ CNTLLING AIABLE _ (
LEANING EXTENSIN FIND GAIN AND S S _ S 0 INESE LTAGE DIIDE 00 k k k G 0 S S m 0. 0 S S
LEANING EXAMPLE If, 3 dc suppls are ± 0 UNDE IDEAL CNDITINS BTH CICUITS SATISFY 8 4 DETEMINE IF BTH IMPLEMENTATINS PDUCE THE FULL ANGE F THE UTPU X, 3 K! 4 X 4 8 K! X X X Y 8 6 8 Y EXCEEDS SUPPLY ALUE. THIS P-AMP SATUATES! P IMPLEMENTATIN
CMPAAT CICUITS Some EAL pamps requre a pull up resstor. ZE-CSSING DETECT
LEANING BY APPLICATIN P-AMP BASED AMMETE NN-INETING AMPLIFIE G I I I GI I I
LEANING EXAMPLE DC MT CNTL - EISITED CHSE NN-INETING AMPLIFIE (WITH PWE P-AMP PA03 B 4 (desgn eq. A Constrants: 0 M Power dsspaton n amplfer 00mW Smplfyng assumptons:, 0 Sgnfcant power losses ccur only n a, b Worst case occurs when m0 P MX (0 00mW A B 4000Ω A B A B 3 ne soluton: 3 kω, kω B Standard alues at 5%! A
DESIGN EXAMPLE: INSTUMENTATIN AMPLIFIE G DESIGN SPECIFICATINS G 0 ANALISIS F PPSED CNFIGUATIN ; Infnte gan A B X @ B : Y 0 @ A : 0 DESIGN EQUATIN: X Y HIGH INPUT ESISTENCE LW PWE DISSIPATIN PEATE FM AA BATTEIES ( SIMPLIFY DESIGN BY MAKING 9 MAX440 eg.., 00 kω, 450kΩ USE LAGE ESISTS F LW PWE
DESIGN EXAMPLE Max o s 0 DESIGN SPECIFICATIN 0 Power loss n resstors should not exceed 00mW when Desgn equatons: P n 0 n (0 00mW Sole desgn equatons (by tral and error f necessary 400Ω n 9 4kΩ
DESIGN EXAMPLE IMPLEMENT THE PEATIN 0.9 0. ANALYSIS F PSSIBLE SLUTIN 0 @ : 0 DESIGN CNSTAINTS AS FEW CMPNENTS AS PSSIBLE MINIMIZE PWE DISSIPATED USE ESISTS N LAGE THAN 0K Gen the functon (weghted sum wth sgn change a basc weghted adder may work 9 0. > > SLE DESIGN EQUATINS USING TIAL AND E IF NECESSAY 0 k,5.6 k,... ANALYZE EACH SLUTIN F THE CNSTAINTS AND FACTS; e.g. D WE USE NLY STANDAD CMPNENTS? DESIGN EQUATINS
DESIGN EXAMPLE DESIGN 4-0mA T 0 5 CNETE. CNET CUENT T LTAGE USING A ESIST I I I CANNT GIE DESIED ANGE!. CHSE ESIST T PIDE THE 5 CHANGE AND SHIFT LEELS DWN! 5 0 MAX MIN 3.5Ω I I 0.00 0.004 MAX I MIN.5 6.5 MUST SHIFT DWN BY.5 (SUBSTACT.5 I ( SHIFT SHIFT ( I SHIFT
LEANING BY DESIGN DES NT LAD PHNGAPH DETEMINE, S THAT IT PIDES AN AMPLIFICATIN F000 ((
LEANING EXAMPLE T 57.45e 0.07T UNITY GAIN BUFFE CMPAAT CICUITS NLY NE LED IS N AT ANY GIEN TIME
MATLAB SIMULATIN F TEMPEATUE SENS WE SHW THE SEQUENCE F MATLAB INSTUCTINS USED T BTAIN THE PLT F THE LTAGE AS FUNCTIN F THE TEMPEATUE»T[60:0.:90]'; %defne a column array of temperature alues» T57.45*exp(-0.07*T; %model of thermstor» X9.3; %computed resstance needed for oltage dder» T3*X./(XT; %oltage dder equaton. Notce./ to create output array» plot(t,t, mo ; %basc plottng nstructon» ttle('utput F TEMPEATUE SENS'; %proper graph labelng tools» xlabel('tempeatue(deg. FAENHEIT'» ylabel('lts'» legend('ltage _T'
EXAMPLE F TANSFE CUE SHWING SATUATIN 0 THIS SUCE CEATES THE FFSET THE TANSFE CUE UTPUT CANNT EXCEED SUPPLY (0 KCL @ _ IN LINEA ANGE FFSET