Lecture 2 February 19 2001 EECS 105 Microelectronics Devices and Circuits Spring 2001 Andrew R Neureuther Topics Value Added by Circuits Reading review of EE 40 HS 1 8 2 2 9 1 Analog Integrated Circuits Overview and Circuit Value Added Revised 1 21 01 How Does a Digital Camera Work l Physics semiconductor junction Photons charge voltage l Analog Circuits Amplify gray level conversion l Digital Circuits Encode store move play l Analog Circuits Display drivers Analog Integrated Circuits Overview and Circuit Value Added Model for Photo Detector l l l l Film sensitivity 3x104 photons QS 3x104 electrons Junction capacitance CJ 30 fF VS Q CJ 3x104x1 6x10 19 3x10 14 VS 160 mV Series resistance RS 200 Ohms VSOURCE VBIAS VS VBIAS Q CJ Analog Integrated Circuits Overview and Circuit Value Added CJ RS Q Q VIN Current to Voltage Conversion l Op Amp Circuit RS Vs CJ RF Q Q iRF VIN VOUT VR KCL Ii 0 VOUT VR RF VBIAS VS VR RS Current Analog Integrated Circuits Overview and Circuit Value Added Remove Bias Op Amps are Ideal but EE 105 is Not l l Ideal Op Amp properties How do we No input current Infinite RIN get these V V Infinite voltage gain With Topic for EE 140 feedback Circuit configurations give the leverage to build nearly ideal circuits from devices with less than ideal properties Don t forget about Op Amps from EE 40 as in EE 105 we will use Op Amps to study circuit concepts like frequency response Analog Integrated Circuits Overview and Circuit Value Added Back to the Future l l l 3 MegaPixels with 3 colors requires nearly 10M OpAmps If each draws 100 A the battery must supply 1000A A car battery would last only 3 minutes Solution Analog switch array of 10 levels and 210 1024 factor of sharing 1024 Photodiodes Resistance and Capacitance of 10 analog switches in series Amplifier RSA 10 10 k 100 k CSA 10 30fF 300 fF Analog Integrated Circuits Overview and Circuit Value Added Model For Switching and Amplifier Approximate effect of CSA by combining it with CJ RSA RS V SCJ Q Q RF iRF VIN CSA VOUT VR VOUT VR RF VBIAS V S VR RS RSA V S is 10 times smaller due to CSA and is now about 15 mV Analog Integrated Circuits From 200 Ohms to 100 200 Ohms 500X smaller signal Overview and Circuit Value Added Simple EE 105 Amplifier RIN 30 k 100 ROUT Infinite RLOAD 10 k R SA RS V SC J Q Q VIN Loop Node iIN iIN RIN ROUT VOUT R LOAD VOUT V S RS RSA RIN RLOAD 115mV Vi 0 iIN Analog Integrated Circuits Ii 0 with Overview and Circuit Value Added R OUT Infinite V S 15 mV Circuit to Hold the Charge Longer Problem CJ Discharges Quickly T CJ RSA 30fF 100k 3 10 10 Sec l l Solution Add Value Through Circuit Design of High Input Resistance Amplifier Analog Integrated Circuits Overview and Circuit Value Added High Input Impedance Circuit RE 30 k RIN EQ RIN 1 RE 3 06 M 23 5 times less current RSA RS iIN Node V S CJ Q Q iIN VIN Note ground connections Loop RIN R OUT RLOAD VOUT RE VOUT V S RS RSA RIN EQ RLOAD 5 mV Vi 0 iIN Analog Integrated Circuits 23 5 times smaller gain Overview and Circuit Value Added Adding a Second Stage Switch V S CJ RSA RS Q Q First Stage Second Stage iIN Node iIN Node iIN VIN RIN Loop R OUT iIN RIN VOUT R LOAD ROUT RE VOUT V S RS RSA RIN EQ1 1 Rin2 1 Rin2 2 ROUT 490 mV Analog Integrated Circuits Overview and Circuit Value Added Visualizing as a Multistage Amplifier Error fixed 1 21 00 Source Switch First Stage iIN RS I1 VS CJ I2 RSA Q Second Stage V1 1V2 RIN RSA 2 RVIN iIN iIN ROUTR iIN IN VOUT ROUT R LOAD 1I1 RIN 3 06M RIN 30k AI 1 AO 1 100 100 ROUT RSA ROUT infinite Analog Integrated Circuits ROUT infinite Overview and Circuit Value Added Visualizing as an Equivalent Two Port RS VS CJ Q VIN RIN VOUT GMVIN R OUT R LOAD RIN RSA RIN EQ1 GM 1 RS RSA RIN EQ1 1 Rin2 1 Rin2 2 ROUT Infinite Assumed Initially Analog Integrated Circuits Overview and Circuit Value Added Multistage Amplifiers This example from the reading in Chapter 8 this week Analog Integrated Circuits Overview and Circuit Value Added Classification of Two Port Amplifiers Voltage Current Transconductance Transresistance Analog Integrated Circuits Overview and Circuit Value Added What Goes in the Amplifier Box BJT MOS Material from Chapter 8 from week 11 Analog Integrated Circuits Overview and Circuit Value Added Small Signal Models for Transistors MOS BJT Week 5 Week 8 Analog Integrated Circuits Overview and Circuit Value Added Layout of Transistors Week 2 Analog Integrated Circuits Week 8 Overview and Circuit Value Added
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