Lecture 0 Op-mp Crcuts ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Characterstcs f Ideal Op mps Infnte gan fr the dfferental nput sgnal Zer gan fr the cmmn-mde mde nput sgnal Infnte nput mpedances Zer utput mpedance Infnte bandwdth ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
eal Versus Ideal Op mp Parameter Typcal ange Ideal Values Open-lp gan 0^5-0^8 Input resstance, 0^5 t 0^3Ω Ω Output resstance, 0 t 00Ω 0 Ω ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
74 Op-mp ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
74 Op-mp Current Mrrrs Output Stage Dfferental mplfer Class mplfer ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
SUMMING-POINT CONSTINT Operatnal amplfers are almst always used wth negate feedback, n whch part f the utput sgnal s returned t the nput n ppstn t the surce sgnal. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
In a negate feedback system, the deal p- amp utput ltage attans the alue needed t frce the dfferental nput ltage and nput current t zer. We call ths fact the summng-pnt cnstrant. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Ideal p-amp crcuts are analyzed by the fllwng steps:. Verfy that negate feedback s present.. ssume that the dfferental nput ltage and the nput current f the p amp are frced t zer. (Ths s the summng-pnt cnstrant.) ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
3. pply standard crcut-analyss prncples, such as Krchhff s laws and Ohm s law, t sle fr the quanttes f nterest. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
The asc Inerter x > 0 << 0 x decreases ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
pplyng the Summng Pnt Cnstrant 0 n n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. n n n
Inertng mplfer Z 0 n n Vut n Zut n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Summng mplfer ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Summng mplfer g F V V V V F V V V V 0 ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. F F F F
Summng mplfer g V t t 0 V 0 V V ut f V ut ut F ut F ut ut 0 V F F ut F ut ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Summng mplfer Input resstance seen by Input resstance seen by Snce the utput ltage des nt depend n the lad resstance L, the utput mpedance s zer. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.(a) Fnd,, x, and : n V m kω x m L L x n ( 0m)(k Ω) 0V 0kΩ V 0 m kω kω 0m m m 0 k Ω kω (V ) ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. n
Exercse 4.(b) V m m k V 5 5 0 5 5 Ω m k V k V m k 5 5 5 0 5 5 3 Ω Ω Ω ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. V k k m m m 5 5 0 5 5 3 4 Ω Ω
Exercse 4.3 ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.3 0 0 Inertng amplfer Summng amplfer ut 0 0 kω 0kΩ 4 0k 0k 0k 0 0k Ω Ω Ω Ω ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Pste Feedback Wth pste feedback, the p amp s nput and utput ltages ncrease n magntude untl the utput ltage reaches ne f ts extremes. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Nn-nertng mplfer g 0 n n n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. n
Nn-nertng mplfer n ut V n 0 V ut n ut 0 n n n ut ut ut n ut n n n n ut ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
NONINVETING MPLIFIES Under the deal-pamp assumptn, the nn- nertng amplfer s an deal ltage amplfer hang nfnte nput resstance and zer utput resstance. n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Vltage Fllwer n 0 ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.4 ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.4 0 0 n n n n 0 n 0 ut n n n n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.4 0 0 n n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Vltage-t-Current Cnerter ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Vltage-t-Current Cnerter n n F ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Exercse 4.6 n 3 n ) ( ) ( ) ( n n n n n 3 3 ) ( ) ( n n n n n n ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc. 3
Desgn f Smple mplfers mplfer desgn usng p amps manly cnssts f selectng a sutable crcut cnfguratn and alues fr the feedback resstrs. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
If the resstances are t small, an mpractcal amunt f current and pwer wll be needed t perate the amplfer. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Very large resstance may be unstable n alue and lead t stray cuplng f undesred sgnals. ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Example 4.3 Want the ltage gan t be -0 ± 5 percent: Varyng resstance ut s S 0 ± 5% Need >> S s that arablty n S s a small percentage change ut S y ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Example 4.3 Chse 00 s 50kΩ S mn 50kΩ S max 50.5kΩ5kΩ max mn 50.5kΩ 50kΩ 50kΩ 0.5 50 % ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.
Example 4.3 T get tthe gan f 0, chse 0 500kΩ Snce, S, can all ary, use % tlerance resstrs: 49.9kΩ ± 499Ω 499kΩ±4.99kΩ ELECTICL ENGINEEING: PINCIPLES ND PPLICTIONS, Furth Edtn, by llan. Hambley, 008 Pearsn Educatn, Inc.