Op-Amp Basics & Linear Applications Dr. S. & S.S. Gandhy Government Engineering College Surat Analog Electronics Op-Amp Basics & Linear Applications Guided By: Prof. N.A. Gajjar

Prepared By: 130230109013 Gajera Marvin 130230109014 Golakiya Dushyant Enrollment No. Name 130230109013 Gajera Marvin 130230109014 Golakiya Dushyant 130230109015 Gosai Mayur 130230109016 Goswami Drashti 130230109017 Hathaliya Bharat

Operational Amplifier + - Non-inverting input Positive voltage supply Negative voltage supply Output Symbol: At a minimum, op-amps have 3 terminals: 2 input and 1 output. An op amp also requires dc power to operate. Often, the op-amp requires both positive and negative voltage supplies (V+ and V-).

Basic Block Diagram V1 Level Shifting Stage Intermediate Stage Out put Stage Input Input Stage Output V2 An Op-Amp can be conveniently divided into Four main blocks: Input Stage Intermediate Stage Level Shifting Stage Output Stage

Input Stage: The input stage is Dual input, balanced output differential. The two inputs are inverting & Non-inverting input terminals. this stage provides most of the voltage gain of the op-amp and decides the input resistance value Ri Intermediate Stage: This is usually another differential amplifier. It is driven by the output of the input stage the stage is dual input unbalanced output differential amplifier.

Level Shifting Stage: Due to direct coupling between the first two stages, the input of level shifting stage is an amplified signal with some non-zero DC level. Level shifting stage is used to bring this DC level to zero with respect to ground. Output Stage: This stage is normally a complementary output stage. It increases the magnitude of voltage and raises the current supplying capability of the op-amp. It also provides a low output resistance.

OP-AMP Pin Identification 1 2 3 4 5 6 7 8 +VCC -VEE - + 741 Notched Package Dot marked Package

OP-AMP Pin Identification Offset Null Inverting Input Non-Inverting Input -VEE Output +VCC N/C

What are These Pins? Pin 1 and Pin 5 : Offset null input, are used to remove the Offset voltage. Pin 2: Inverting input (-Vin), signals at this pin will be inverted at output Pin 6. Pin 3: Non-inverting input (+Vin), signals at pin 3 will be processed without inversion. Pin 4: Negative power supply terminal (-VEE). Pin 6: Output (Vout) of the Op-Amp Pin 7: Positive power supply terminal (+VCC) Pin 8: No connection (N\C), it is just there to make it a standard 8-pin.

OP-AMP Terms Op-Amp: An active circuit element designed to perform mathematical operations of addition, subtraction, multiplication, division, differentiation and integration. High performance linear amplifier that requires a power source to operate. Gain: Amount of amplification produced by an Op-Amp. Gain is independent from the supply voltage (power given for the Op-Amp to operate).

Open-Loop Mode: Function of an Op-Amp when the feedback resistor (Rf) is zero. The Op-Amp operates as a comparator and not as a linear amplifier. Comparator: Compares the –V and +V inputs to see which is greater and returns a result. Bandwidth: The range of frequency at which an Op-Amp will function. (Ideal = ∞)

Input Offset Voltage: Even when there is no input voltage the Op-Amp gives off a small voltage. This can be canceled out by use of the Offset Null pin on the chip. Common Mode Rejection Ratio (CMRR): Ability of an Op-Amp to reject a signal applied to both inputs simultaneously. Slew Rate (V/µs): Amount of time it takes for the Op-Amp to step to another voltage level. (Non-Ideal)

Typical OP-AMP Parameters Variable Typical Ranges Ideal Values Open-Loop Voltage Gain A 105 to 108 ∞ Input Resistance Ri 105 to 1013 W ∞ W Output Resistance Ro 10 to 100 W 0 W Supply Voltage Vcc/V+ -Vcc/V- 5 to 30 V -30V to 0V N/A

741 OP-AMP Maximum Ratings: Characteristics: Supply Voltage ±18 V Power Dissipation 500 mW Diff. Input Voltage ±30 V Input Voltage ±15 V Operating Temperature 0°C to 70°C Characteristics: Input Offset Voltage 2 to 6 mV Input Resistance 3 to 2 MΩ CMMR 70 to 90 dB Bandwidth 0.5 to 1.5 MHz Slew Rate 0.5 V/µs Offset Null Unused 1 2 3 4 5 6 7 8 - IN + + V - + IN Out Offset Null - V

Integrated Circuit Types The ICs are broadly Categorized into TWO classes as: 1. Digital ICs 2. Linear ICs Linear ICs are equivalent of Descrete Transistor circuits such as amplifier, filters, etc. The linear ICs are also known as the Analog ICs of all the available linear ICs almost all are operational amplifier. We can classify the integrated circuits into TWO classes based on the technology used. The Two classes are: 1. Monolithic Technology 2. Hybrid Technology

Inside an IC

Further Classification of IC technology is shown below.

Monolithic ICs: In this type of ICs, all the circuit components, and their interactions are manufactured into or on top of a single chip of Silicon. that is why the name monolithic. The technology is ideally suitable when identical circuits are required in a very large number. The monolithic circuits are further classified into TWO categories namely “Bipolar” & “Unipolar”. The advantages of monolithic technology are: 1. Low per unit cost 2. Very high reliability

Classification based on Active devices: Hybrid ICs: The hybrid circuits are completely different from the monolithic ones. In hybrid circuits, separate component parts are first attached to a Ceramic substrate. Then these parts are interconnected by means of either metallization pattern or wire bonds to form the circuits. Classification based on Active devices: Depending upon the type of active device being used, the ICs can be classified as Bipolar ICs (which use bipolar junction transistor) and Unipolar ICs (which use field effect transistors). The bipolar and Unipolar ICs are further classified depending on the isolation technique or type of FET (JFET or MOSFET)

Linear Applications of OP-AMP There are many applications of an OP-AMP. Voltage Adder (Summing Amplifier) Difference Amplifier Integrator Differentiator Voltage Follower & etc…

Voltage Adder (Summing Amplifier) Application : For Noise Cancellation

Difference Amplifier If R1 = R2 and Rf = Rg:

Integrator R C Vin Vo The input is integrated with respect to time.

Differentiator R2 R1 Vin Vo C R3

Voltage Follower It is a non inverting amplifier with gain=1 Vin It is a non inverting amplifier with gain=1 So the output is the same as input.

And That’s It…