LINEAR INTEGRATED CIRCUITS ANDAPPLICATIONS

• LTP 300

• Text Book :Op-Amps & Linear Ics by Ramakanth A. Gayakwad

contents• Unit I

• Introduction to Operational Amplifiers : Ideal Op-Amp, Block diagram

• Representation of Operational amplifier, Voltage Transfer Curve of Op-Amp,

• Integrated Circuit Package Types, Pin Identification and Temperature Ranges,

• Interpretation of Data sheets of an Op-amp

• Operational Amplifier Configurations : Open loop configuration, Closed loop

• configurations, Block diagram representation of Feedback Configurations, voltage

• followers & High input impedance configuration, Differential amplifier

• Unit II

• Practical Operational Amplifier : AC characteristics, DC characteristics, CMRR

• Frequency response of an Operational Amplifier : Frequency response

• compensator networks, Frequency response of internally compensated OP-AMP & non-compensated OP-AMP, High frequency OP-AMP equivalent circuit, Open loop voltage gain as a function of frequency, Slew Rate causes and effects

• Unit III

• General Applications of Operational Amplifier : Summing, Scaling and averaging

• amplifier, V to I and I to V converter, Integrator and Differentiator, Log and anti-log amplifier, Instrumentation amplifier

• Unit IV• Comparators and Converters : Basic comparator & its characteristics, Zero• crossing detector, clipper and clamper, Voltage to frequency converter and frequency• to voltage converters, Sample and hold circuit• Oscillators : Oscillator principle, Types of Oscillators, Phase Shift Oscillator, Wien• Bridge Oscillator, Square wave,triangular wave and saw tooth wave generators,• Voltage Control Oscillator(VCO)• Unit V• Timers and Phase Lock Loop(PLL) : Introduction to 555 timer, Detailed Operation• of 555 timer IC, Applications of 555 Timer IC, Phase lock Loop(PLL)- Introduction,• block schematics and Working principle• A to D and D to A Converters : Introduction, ADC conversion techniques, IC 1408• Operation, DAC conversion techniques, ADC & DAC Specifications• Unit VI• Active filters : Introduction to active filters, Advantages and classifications of Active• Filters, 1st order LPF, HPF,BPF , Band Reject Filter and All pass filter

Academic tasks

Operational Amplifiers

What is an operational amplifier? This particular form of amplifier had the name “Operational” attached to it many years ago.

As early as 1952, Philbrick Operational Amplifiers (marketed by George A. Philbrick) were constructed with vacuum tubes and were used in analog computers.* Even as late as 1965, vacuum tube operational amplifiers were still in use and cost in the range of $75. * Some reports say that Loebe Julie actually developed the operational amplifier circuitry.

2

Basic Electric Circuits

Operational Amplifiers

The Philbrick Operational Amplifier.

From “Operational Amplifier”, by Tony van Roon: http://www.uoguelph.ca/~antoon/gadgets/741/741.html

Operational Amplifiers

My belief is that “operational” was used as a descriptorearly-on because this form of amplifier can performoperations of

• adding signals

• subtracting signals

• integrating signals, dttx )(

The applications of operational amplifiers ( shortenedto op amp ) have grown beyond those listed above.

3

Operational Amplifiers

At this level of study we will be concerned with howto use the op amp as a device.

The internal configuration (design) is beyond basiccircuit theory and will be studied in later electroniccourses. The complexity is illustrated in the followingcircuit.

4

Operational Amplifiers

The op amp is built using VLSI techniques. The circuitdiagram of an LM 741 from National Semiconductor isshown below.

5

V+

V-

Vo

Vin(-)

Vin(+)

Figure 8.1: Internal circuitry of LM741.Taken from National Semiconductor

data sheet as shown on the web.

Operational Amplifiers

Fortunately, we do not have to sweat a circuit with 22transistors and twelve resistors in order to use the op amp

The circuit in the previous slide is usually encapsulated intoa dual in-line pack (DIP). For a single LM741, the pin connections for the chip are shown below.

Taken from National Semiconductordata sheet as shown on the web.6

Figure 8.2: Pin connection, LM741.

Operational Amplifiers

i n ve r t i n g i n p u t

n o n i n ve r t i n g i n p u to u t p u t

V -

V +

The basic op amp with supply voltage included is shownin the diagram below.

7

Figure 8.3: Basic op am diagram with supply voltage.

Operational Amplifiers

In most cases only the two inputs and the output areshown for the op amp. However, one should keep inmind that supply voltage is required, and a ground.The basic op am without a ground is shown below.

8Figure 8.4: Outer op am diagram.

Operational Amplifiers

A model of the op amp, with respect to the symbol, isshown below.

V 1

V 2

_

+

V d R i

R o

A V d

V o

Figure 8.5: Op Amp Model.9

ECE 201 Circuit Theory I 15

Ideal OP AMP (Open Loop)

( )

0

o p n

in

p n

p n

v A v v

R

A

v v

i i

A

A = “open-loop” gain

Through-hole

• Single in-line package: SIP

• Dual in-line package (DIP)

• CDIP: Ceramic DIP[1]

• CERDIP: glass sealed ceramic DIP[1]

• QIP: Quadruple in-line package, like DIP but with staggered (zig-zag) pins.[1]

• SDIP: Skinny DIP

• ZIP: Zig-zag in-line package

• MDIP: Molded DIP[2]

• PDIP: Plastic DIP[1]

SMD

• CCGA: ceramic column grid array (CGA)

• CGA: column grid array

• CERPACK: ceramic package [4]

• CQGP:[5]

• LLP: Lead Less lead frame Package, a package with metric pin distribution

• LGA: Land Grid Array

• LTCC: Low temperature co-fired ceramic [7]

• MCM: Multi-Chip Module [8]

• MICRO SMDXT: micro Surface Mount Device extended technology [9]

Chip carrierA chip carrier is a rectangular package with contacts on all four edges. Leaded chip carriers have metal leads wrapped around the edge of the package, in the shape of a letter J. Leadless chip carriers have metal pads on the edges. Chip carrier packages may be made of

ceramic or plastic and are usually secured to a printed circuit board by soldering, though sockets can be used for testing

• BCC: Bump Chip Carrier [3]

• CLCC: Ceramic Leadless Chip Carrier [1]

• LCC: Leadless Chip Carrier, contacts are recessed vertically.[3]

• LCC: Leaded Chip Carrier [3]

• LCCC: Leaded Ceramic Chip Carrier • DLCC: Dual Lead-Less Chip Carrier (Ceramic)

PLCC: Plastic Leaded Chip Carrier

Pin grid arrays

• OPGA: Organic Pin Grid Array

• FCPGA: Flip-chip Pin Grid Array [3]

• PAC: Pin Array Cartridge [10]

• PGA: Pin grid array (also known as PPGA) CPGA: Ceramic Pin Grid Array

Flat packages

• Flat pack, early metal/ceramic case with flat leads

• CFP: Ceramic Flat Pack [3]

• CQFP: ceramic quad flat-pack, similar to PQFP

• BQFP: Bumpered Quad Flat Pack [3]

• DFN: Dual Flat Pack, No Lead [3]

• ETQFP: Exposed Thin Quad Flat Package [11]

• PQFN: power quad flat-pack, no-leads, with exposed die-pad[s] for heatsinking [12]

• PQFP: Plastic quad flat package [1][3]

• LQFP: Low-profile Quad Flat Package [3]

• QFN: Quad Flat No Leads, also called micro lead frame (MLF).[3][13]

• Quad Flat Package: (QFP) [1][3]

• MQFP - Metric Quad Flat Pack,a QFP with metric pin distribution [3]

• HVQFN: Heat-sink very-thin quad flat-pack no-leads

• TQFP: Thin Quad Flat Pack [1][3]

• TQFN: Thin Quad Flat No-Lead

• VQFP: Very-thin Quad Flat Pack [3]

Small outline packages• CSOP: ceramic SOP

• MSOP: Mini Small-Outline Package

• PSOP: Plastic small-outline package [3]

• PSON: Plastic small-outline no lead package

• QSOP: Quarter-Size Small-Outline package, with pin spacing of 0.635 mm.[3]

• SOIC: Small Outline Integrated Circuit (Also SOIC NARROW and SOIC WIDE).

• SOP: Small Outline Package [1]

• SSOP: Shrink Small-Outline Package [3]

• TSOP: Thin Small-outline Package [3]

• TSSOP: Thin Shrink Small Outline Package [3]

• TVSOP: Thin Very Small-Outline Package [3]

• µMAX: Similar to a SOIC.

• WSON: Very Very Thin Small Outline No Lead Package

BGA

– FBGA: fine pitch ball grid array, with a square or rectangular array of solder balls on one surface [3]

– LBGA : Low Profile Ball Grid Array (see BGA) (also Laminate Ball Grid Array) [3]

– TEPBGA: Thermally Enhanced Plastic BGA.– CBGA: Ceramic Ball Grid Array [3]

– OBGA: Organic Ball Grid Array [3]

– TFBGA - thin fine pitch BGA.[3]

– PBGA: Plastic Ball Grid Array [3]

– UCSP: Similar to a BGA (A Maxim trademark example) [17]

– μBGA - micro-BGA (Ball grid array), with ball spacing less than 1 mm– LFBGA - low profile fine pitch ball grid array [3]

– TBGA: Thin Ball Grid Array [3]

– SBGA: Super BGA - above 500 Pin count [3]

– UFBGA: Ultra Fine BGA [3]

Chip-scale packages

• CSP: Chip Scale Package (package no more than 1.2x the size of the silicon chip)

• TCSP: True Chip Size Package (package is same size as silicon) [18]

• TDSP: True Die Size Package (same as TCSP) [18]

• MICRO SMD: a chip-size package (CSP) developed by National Semiconductor [19]

• COB: chip-on-board; a bare silicon chip, that is usually an integrated circuit, is supplied without a package.

• COF: chip-on-flex; a variation of COB, where a chip is mounted directly to a flex circuit.

• COG: chip-on-glass; a variation of COB, where a chip is mounted directly to a piece of glass - typically an LCD.

Open loop OPAMP Configuration

• In the case of amplifiers the term open loop indicates that no connection, exists between input and output terminals of any type. That is, the output signal is not fedback in any form as part of the input signal.

• In open loop configuration, The OPAMP functions as a high gain amplifier. There are three open loop OPAMP configurations

open loop differential amplifier in which input signals vin1 and vin2 are applied to

the positive and negative input terminals.

• Since the OPAMP amplifies the difference the between the two input signals, this configuration is called the differential amplifier. The OPAMP amplifies both ac and dc input signals. The source resistance Rin1 and Rin2 are normally negligible compared to the input resistance Ri. Therefore voltage drop across these resistances can be assumed to be zero.

• Therefore

• v1 = vin1 and v2 = vin2.

• vo = Ad (vin1 – vin2 )

• where, Ad is the open loop gain.

Operational Amplifiers (Op Amps)

Discussion D3.1

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

The Inverting Amplifier: If the input is applied to only inverting terminal and non-inverting terminal is

grounded then it is called inverting amplifier.v1= 0, v2 = vin.

vo = -Ad vin

• The negative sign indicates that the output voltage is out of phase with respect to input 180 ° or is of opposite polarity. Thus the input signal is amplified and inverted also.

The non-inverting amplifier:  

• In this configuration, the input voltage is applied to non-inverting terminals and inverting terminal is ground .

• v1 = +vin                  v2 = 0

• vo = +Ad vin

• This means that the input voltage is amplified by Ad and there is no phase reversal at the output.

• In all there configurations any input signal slightly greater than zero drive the output to saturation level. This is because of very high gain. Thus when operated in open-loop, the output of the OPAMP is either negative or positive saturation or switches between positive and negative saturation levels. Therefore open loop op-amp is not used in linear applications

Ideal Op Amp

1) 0 vv A v v

The open-loop gain, Av, is very large, approaching infinity.

2) 0i i The current into the inputs are zero.

+

-

i

ov

v

vi

DDV

SSV

0SS DDV v V

Ideal Op Amp with Negative Feedback+

-ov

v

v

Network

Golden Rules of Op Amps:

1. The output attempts to do whatever is necessary to make the voltage difference between the inputs zero.

2. The inputs draw no current.

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Non-inverting Amplifier

+

-

1R2R

ivov

v

v oF

i

vA

v

2

1

1oF

i

v RA

v R

1

1 2i o

Rv v v v

R R

Closed-loop voltage gain

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Unity-Gain Buffer

+

-ov

v

v

ivo

Fi

vA

v

1oF

i

vA

v

i ov v v v

Closed-loop voltage gain

Used as a "line driver" that transforms a high input impedance (resistance) to a low output impedance. Can provide substantial current gain.

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Inverting Amplifier

0v v

1 1

0i ii

v vi

R R

Current into op amp is zero

+

-

1R

2R

ivov

v

vii ii

0 0

2 2

0i

v vi

R R

2

1

oF

i

v RA

v R

0

1 2

iv v

R R

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Differential Amplifier

v v

11

1

v vi

R

Current into op amp is zero

01

2

v vi

R

+

-1R

2R

1vovv

v1i

1i

2v1R

2R

22

1 2

Rv v

R R

01

1 2

v vv v

R R

2 21 2 2 0

1 2 1 2

1 2

R Rv v v v

R R R R

R R

Differential Amplifier

+

-1R

2R

1vovv

v1i

1i

2v1R

2R

2 21 2 2 0

1 2 1 2

1 2

R Rv v v v

R R R R

R R

2

2 2 20 1 2 2

1 1 2 1 1 2

R R Rv v v v

R R R R R R

2 2 20 1 2

1 1 2 1

1R R R

v v vR R R R

20 2 1

1

Rv v v

R

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Current-to-Voltage Converter

i fi i

0v v

00 f Fv i R

0 i Fv i R

0Transresistance i Fv i R

+

-ov

v

v

ii

FR fi

Photodiode Circuit25 A per milliwatt of incident radiationii

650 25 10 1.25mAii

Assume 3.2kFR

3 30 1.25 10 3.2 10 4Vi Fv i R

+

-ov

v

v

ii

FR fi

h At 50 mW

Operational Amplifiers (Op Amps)

• Ideal Op Amp

• Non-inverting Amplifier

• Unity-Gain Buffer

• Inverting Amplifier

• Differential Amplifier

• Current-to-Voltage Converter

• Non-ideal Op Amp

Non-ideal Op Amp• Output voltage is limited by supply voltage(s)• Finite gain (~105)• Limited frequency response• Finite input resistance (not infinite)• Finite output resistance (not zero)• Finite slew rate• Input bias currents• Input bias current offset• Input offset voltage• Finite common mode rejection ratio (CMRR)

0slew rate ( ) MAXdv t dt