4. OPERATIONAL AMPLIFIERS CIRCUITS by Ulaby & Maharbiz All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 5: IC Fabrication Wafer: Thin slice of semiconductor material with highly polished surface Processed wafer is cut into many dies or chips. Lithography: Defining spatial pattern Photoresist: Polymer material that does not allow etching or deposition of areas underneath it. All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 5: IC Fabrication All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Lithography: Defining spatial pattern Photoresist: Polymer material that does not allow etching or deposition of areas underneath it. Tech Brief 5: IC Fabrication All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 5: IC Fabrication All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 5: IC Fabrication All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 5: IC Fabrication All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Operational Amplifier “Op Amp”  Two input terminals, positive (non- inverting) and negative (inverting)  One output  Power supply V +, and Op Amp showing power supply Op Amp with power supply not shown (which is how we usually display op amp circuits) All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Inside The Op-Amp (741) All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Gain  Key important aspect of op amp: high voltage gain  Output, A is op-amp gain (or open-loop gain) – different from circuit gain G  Linear response All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Equivalent Circuit All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-1: Op Amp Amplifier KCL at Node a: KCL at Node b: For infinite A: = = 5 Node a Node b All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Negative Feedback  Feedback: return some of the output to the input  Negative feedback decreases input signal  Achieves desired circuit gain, with wide range for input Negative Feedback No Feedback Range of 5 Gain = 5Range of : ‒ 2 V to +2 V Gain = 1million Range of : ‒ 10 mV to +10 mV All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Negative Feedback All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Circuit Analysis With Ideal Op Amps  Use nodal analysis as before, but with “golden rules”   N  Do not apply KCL at op amp output No current into op amp No voltage drop across op amp input All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Noninverting Amplifier (max) = V cc At node All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Inverting Amplifier All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-2: Input Current Source Relate output voltage to input current source All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Summing Amplifier All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-3: Solution: All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Difference Amplifier Note negative gain of channel 1 All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Voltage Follower “Buffers” Sections of Circuit What is the op amp doing? depends on both input and load resistors is immune to input and load resistors All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-5: Elevation Sensor Sensor Response Desired Output h = elevation, inversely proportional to air pressure All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-6: Multiple Op-Amp Circuit All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Measurement Uncertainty (T = 21 ° C) v2v2 V 0 = V 2 ± 1% of V 2 21 ° C ± 0.21 ° C G = 1 ± 1% G = 1 1% G = 1 1% v2v2 (T = 21 ° C) Thermistor v1v1 Fixed Reference Temp = 20 ° C V 0 = (V 2 ‒ V 1 ) ± 1% of (V 2 ‒ V 1 ) 1 ° C ± 0.01 ° C Direct Measurement Differential Measurement Much better measurement uncertainty All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Instrumentation Amplifier Highly sensitive differential amplifier All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Digital to Analog Converter Converts digital value into analog voltage 4-digit example All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Digital to Analog Converter Represent digital value with analog voltage All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

MOSFET (Field Effect Transistor) Active Device: Voltage Controlled Current Source Gate voltage controls drain/source current All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

MOSFET Equivalent Circuit Characteristic curvesIdealized response All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example 4-9: MOSFET Amplifier Given: Determine All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Load Line You can use a “load line” to graphically determine V out = V DS for a given V in = V GS RLRL V DD V DD / R D All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Digital Circuit: MOSFET Inverter V DD = 15 V RLRL G S D IDID Output “High” Logic 1 Output “Low” Logic 0 InOut Input “Low” InOut V DD V GS =V in V DS =V out Output “Low” Logic 0 Output “High” Logic 1 Input “High” All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Read-Only Memory (ROM) Circuits V READ = 1 V BIT = 0100 All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Another Digital Circuit Element: NAND ABOut A B V DD A V out B No current flows through resistor, unless both A and B inputs turn their transistors on to “pull down” V out NAND gates can be used to build any binary logic function All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Another Digital Circuit Element: NOR Current will flow if either A or B inputs turn their transistors on to “pull down” V out ABOut A B A V DD V out B NOR gates can be used to build any binary logic function All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Example: Multisim Instruments All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Multisim Table All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Multisim: MOSFET I-V Analyzer All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 6: Display Technologies All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Tech Brief 6: Display Technologies Digital Light Processing (DLP) All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Summary All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press