*A Deep Dive into MOSFETs: Understanding the Foundation of Modern Electronics* * *0:00:07** Introduction to MOSFETs:* The lecture begins with an introduction to Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), highlighting their complexity and fundamental role in integrated circuits. * *0:00:47** MOSFET Basics:* MOSFETs are the basic components of digital integrated circuits, characterized by three terminals: gate, source, and drain. * *0:01:19** MOSFET Structure:* The structure involves implanting dopants (e.g., phosphorus) into the silicon surface to create regions with higher electron concentrations. * *0:01:45** MOSFET Length and Width:* The length is defined as the distance between the source and drain, while the width influences the current carrying capacity. * *0:02:57** MOSFET Flavors:* MOSFETs come in various types, such as 1.8V n-type and p-type in the Skywater 130 technology, differing in charge carriers (electrons or holes). * *0:03:38** Field Effect:* The MOSFET operation relies on the field effect, where modulating the gate-source voltage controls current flow between the drain and source. * *0:05:33** Depletion Region:* At a certain gate voltage, a depletion region forms, followed by a thin sheet of free electrons enabling current flow. * *0:06:46** Quantum Mechanics:* The formation of the electron sheet is governed by quantum mechanics, resulting in a non-uniform electron density just below the silicon surface. * *0:07:12** Current Flow and Pinch-Off:* Increasing the drain voltage initially increases current linearly, but beyond a threshold, the current saturates due to pinch-off, where the electron sheet disconnects from the drain. * *0:08:39** Logic Gates:* MOSFETs can create logic gates like inverters and NAND gates, essential for digital circuits. * *0:10:59** Weak and Strong Inversion:* Different equations govern MOSFET behavior in weak inversion (subthreshold) and strong inversion, depending on the gate-source voltage relative to the threshold voltage. * *0:12:56** Energy Band Diagram:* The energy band diagram illustrates how applying a gate voltage modulates the energy barrier, affecting electron injection and current flow. * *0:16:41** Subthreshold Leakage:* A small current can flow even at zero gate voltage due to the reduction of the energy barrier at the drain side, known as subthreshold leakage. * *0:18:51** Electron Injection:* Modulating the gate voltage changes the energy barrier, exponentially affecting electron injection and current. * *0:21:58** Threshold Voltage:* The threshold voltage is defined as the gate-source voltage at which the density of electrons in the inversion layer equals the density of holes far from the channel. * *0:23:38** Strong Inversion Operation:* In strong inversion, a conductive sheet of electrons forms, and current flow is primarily due to drift current. * *0:28:44** Quantum Effects in Small Transistors:* In very small transistors, quantum effects become significant, with the electron density peaking slightly below the surface. * *0:30:24** Small Signal Model:* A small signal model is introduced to analyze MOSFET behavior at low frequencies, considering transconductance and output resistance. * *0:31:30** Transconductance Equations:* Equations for transconductance in strong and weak inversion are presented, highlighting the dependence on gate-source voltage and threshold voltage. * *0:33:46** Moderate Inversion:* Moderate inversion is a common operating region in modern technologies, and models accurately predict behavior in this region. * *0:35:33** Strong Inversion Current Equation:* The current equation in strong inversion is proportional to the square of the effective gate voltage. * *0:37:49** Pinch-Off Effect:* Increasing the drain-source voltage beyond a certain point leads to pinch-off, where the current saturates due to the formation of a depletion region. * *0:39:56** High-Frequency Model:* At high frequencies, capacitances between terminals become significant and are included in the small signal model. * *0:42:41** Intrinsic Gain:* The intrinsic gain of a MOSFET is defined as the ratio of transconductance to output conductance, which decreases with increasing gate-source voltage. * *0:44:02** Bulk Effect:* The threshold voltage depends on the bulk-source potential, introducing an additional current component dependent on the bulk-source voltage. * *0:46:39** Capacitance Effects:* Various capacitances exist in MOSFETs, including gate-source, gate-drain, source-bulk, and drain-bulk capacitances, affecting high-frequency performance. * *0:47:57** Weak Inversion Behavior:* In weak inversion, current flow is primarily due to diffusion, and transconductance is higher compared to strong inversion for the same current. * *0:50:45** Velocity Saturation:* Electrons have a speed limit, affecting current flow at high electric fields and leading to deviations from the square law model. * *0:54:22** MOSFET Scaling:* The trend of scaling down MOSFET dimensions has led to increased complexities and the need for advanced fabrication techniques. * *0:57:31** Drain-Induced Barrier Lowering (DIBL):* In small transistors, increasing the drain voltage can reduce the energy barrier at the source side, increasing current and effectively acting as an additional resistance. * *0:58:46** Well Proximity Effect:* The doping concentration can vary near the edge of a well due to ion scattering during implantation, affecting the threshold voltage of nearby transistors. * *0:59:59** Stress Effects:* Mechanical stress can alter the mobility of charge carriers by modifying the band structure, affecting current flow and introducing variability. * *1:01:54** Gate Oxide Leakage:* Thinning the gate oxide can lead to electron tunneling, causing gate leakage current, a problem addressed by using high-k dielectric materials. * *1:03:21** Hot Carrier Injection:* High electric fields can accelerate electrons, leading to impact ionization and potential injection of hot carriers into the gate oxide, degrading transistor performance over time. * *1:05:09** Channel-Initiated Secondary Electron Generation:* In certain configurations, holes can accelerate and create electron-hole pairs, with the electrons potentially getting injected into the gate. * *1:05:59** Variability in MOSFETs:* Various factors, including voltage, layout, process, temperature, and random variations, contribute to variability in MOSFET performance. * *1:07:45** Temperature Effects:* Temperature affects mobility and threshold voltage, with competing effects on transistor speed. * *1:08:53** Random Variation and Mismatch:* Random variations in doping and dimensions lead to mismatch between transistors, which can be modeled using Pelgrom's model. * *1:12:56** Optimizing for Mismatch:* Operating in strong inversion and using larger transistor areas can help reduce mismatch. * *1:14:57** Noise in MOSFETs:* Thermal noise, flicker noise, and popcorn noise are present in MOSFETs, affecting circuit performance. * *1:17:33** Conclusion:* The lecture provides a comprehensive overview of MOSFETs, covering their fundamental principles, operating regions, various effects, and considerations for analog circuit design. I used gemini-1.5-pro-exp-0827 on rocketrecap dot com to summarize the transcript. Cost (if I didn't use the free tier): $0.11 Input tokens: 81953 Output tokens: 1653

Just wanted to report that the "shutil.copytree()" function in ../common/staging_install.py seems to be broken? Had to change arguments to "symlinks=True, ignore_dangling_symlinks=True" and remove the verbose argument. Also the step we are supposed to do around the 10:00 min mark, in my folders, only rply and sky130B show up, sky130A and SUN_SAR9B_SKY130NM do not show up at all. Am i doing something wrong? My environment is Ubuntu 22.04 in WSL on windows 10 using python3.10.12 if it helps.

Legendary work

Thank you so much for sharing such valuable content. I was wondering if you could recommend any resources for learning how to analyze simple switched-capacitor circuits, such as voltage doublers. These types of circuits are sometimes brought up during interviews, and I find it challenging to analyze them if I'm unfamiliar with the structure beforehand. Any guidance would be greatly appreciated!

Thank god, wasn't able to afford to finish my bachelors so graduate paths have been blocked for me. I did zero2asic but I paid out of pocket and I've been missing analog stuff, thanks for contributing to the things people like me can easily learn for free.

to me, intuitively, complex means many parts, complicated means convoluted interactions between parts

Thank you for another great video. Could you please explain the Analog standard library that you created? I’m curious about how you built that library and the details of its specifications, such as gm/id, Vov, and so on. Thank you!

Hi, Sir, could you tell me whether we who are not part of NTNU can access the slides, assignments, etc......

Can I take this course?

Legends people who work for youth never die. You are one of them ❤

*Mixed-Signal Simulation in Ngspice: Combining Digital and Analog Worlds* * *0:00** Introduction:* Overview of mixed-signal simulation, combining digital and analog components. * *0:40** Digital Simulation:* Discussion of digital simulators, their causal nature, and the use of languages like Verilog/SystemVerilog. A simple counter example in SystemVerilog is presented. * *5:00** Analog Simulation:* Explanation of analog simulation, its challenges due to non-linearity and varying time constants, and the use of numerical methods to solve differential equations. Commercial and open-source simulators are listed (Spectre, ngspice, etc.). * *7:37** Mixed-Signal Simulation:* Description of the interaction between digital and analog simulators, including signal translation and synchronization. * *9:20** Demo Start:* Practical demonstration of mixed-signal simulation using ngspice and SystemVerilog. * *11:00** Analog Schematic:* Review of the analog circuit (current mirror and 5-bit current DAC) used in the demo. * *12:33** Digital Code:* Overview of the digital code (counter) that controls the DAC. * *12:40** Compiling Digital Code:* Using verilator to compile the SystemVerilog code into a shared object (.so) file. * *15:40** Including in Ngspice:* Using a Perl script to generate the necessary Ngspice code for incorporating the compiled digital code. This includes instantiation, connecting dummy resistors to inputs/outputs, and converting the digital bus output to a real value for easier viewing. * *19:48** Testbench:* Explanation of the Ngspice testbench, including clock and reset generation, inclusion of the analog and digital components, and voltage sources for current measurement. * *21:53** Setting Digital Levels:* Overriding default digital output levels for compatibility with the analog circuit. * *22:16** Running the Simulation:* Executing the simulation using `make typical`. * *24:56** Viewing Waveforms:* Using a waveform viewer to analyze the simulation results, observing the DAC current changing with the digital counter output. I used gemini-exp-1121 on rocketrecap dot com to summarize the transcript. Input tokens: 22271 Output tokens: 455

Hi, could you please upload the video lectures, assignments and projects?

Dear author, Thank you very much for the video! I like you use real design as an example and it is very well-explain. I am a designer myself, but I have a few questions about the SW capacitors, 1. if you use it in the FB with an opamp, for example at 46:02, should the sampling frequency be faster or smaller than opam? If it is slower, opamp will not see the spike, however, will it be able to charge to the proper value? 2. in 46:02 again, will you add an LPF to filter out the spike? Thank you very much again for your video, I really appreciate it!

Thank you very much for your sharing. This is a fantastic tool! I would like to ask if dicex exercises in 2021 is a course or self-study material. Are there any other related PDFs or courses available? Thank you!

Thank you for the video! Is there a reason you like mac? Just that its UNIX based? It seems like they get a lot of bad flak by engineers unjustly so imo.

Wow awsome explaination 😇

I was doing some analog design with skywater and one of the fets has got width of near 0.35, which can only contain one contact. Should I redesign the ckt or is it ok?

thanks for sharing a great tutorial about using open source circuit tools.

Note: In this lecture, you refer to k as the momentum vector and functions of k as being "in the momentum space". In standard terminology, this is the wave vector and functions over it are "reciprocal space" since k is reciprocal with regards to spatial dimensions, its unit is 1/meter

Great video! I like the philosophical comments in those videos. BTW, that Antenna book (If I saw correctly on the shelf), by Balanis, is excelent (along with his book on advanced electromagnetics) !

Thanks for the great content.

The VI convertor circuit show at 35:20 has the op amp inputs wrong. Band gap source should be connected to +in and RSense feedback to -in of opamp

Simply the best content you can find on KZbin. Just to let you know how much this content is appreciated, I used your favorite OTA in my current tapeout.

7:42

Amazing how similar your design decisions are too PCB design decisions, except yours are based on Quantum theory, whereas PCB are based on Maxwell's equations :)

Incredible video, I loved both the review of SPICE and Analog Design, and especially the GitHub Actions workflow with NGSpice, I'm wanting to do something similar for mixed signal simulation as a T.A for a course at my university, I'll definitely use this repository for inspiration.

how is this channel not more popular

Amazing videos. Thanks alot for your time.

What spectacular timing, I just started diving into what is involved in developing SPICE models as my group will likely be requiring a novel DAC for a specific use in a cryogenic environment in the next few years. It's unlikely I will play a role in this, given my lack of education and skills in this domain, but my curiosity compels me. Thank you so much for the educational content and material you provide!

Thank you !! Great video

Thank you.

Great one! ❤

Analog design professional here! Just created a channel to comment how incredible this lecture is.. Thanks professor..

I thought this was going to be about Dune. Dune is all about Spice you know.

Wow, this was great.

Glad that I found your playlist. I am an electronics engineering student but I am not knowledgeable by any means in computer science. How can I learn to do circuit design and related tasks in code, like the examples you show? Any recommendations for resources or steps to get started would be greatly appreciated!

you are an exceptional professor with a calm and soothing voice. Listening to you nakes your videos both benefecial and comfortable. This might comment sound unusual, but it's truly what i feel after watching countless educational videos about AICD Keep sharing the right content :)

Great presentation. How many metal layers can be used in this projetc? Thanks

Did you place dummy transistors in the layout ? Active devices might cause leakage without them. Also does it allow to do EM simulations ?

Your presentation is wonderful. The amount of work involved in your compiler… and making it avaliable as open source… definitely helping to enable the next generation of developers. A life time of learning is not enough to learn everything in analog/digital ic design.

Any video of Magic Layout with higher metal layers and vias, I am facing some issues in dealing with vias and higher metals??

I am not able to see the option of adding Devices in Magic 8.3. Can i add this freatures

Most designers are not coders , pretty divergent discipline

1:07:31 Hello Sir, Is the Barkhausen criterion applicable to this type of oscillator to guarantee oscillation, if yes how to apply the criteria here? Thanks for the lecture.

*Abstract* This lecture explores various energy harvesting techniques and their applications in powering electronic circuits. It delves into the principles, advantages, and limitations of thermoelectric, photovoltaic, piezoelectric, electromagnetic, and triboelectric energy generation. The lecture emphasizes the importance of understanding the specific use case and energy source to design efficient harvesting circuits. It concludes by highlighting the need to minimize the average current consumption of electronic devices to enable a future of batteryless IoT sensors powered by harvested energy. *Summary* *Introduction (**0:01**)* - Electronic circuits require energy sources to function, traditionally batteries or AC adapters. - Energy harvesting offers an alternative for long-term operation without battery replacements. - The choice of energy harvesting technique depends on the application and desired power consumption. *Energy Harvesting Techniques* *Thermoelectric (**7:47**)* - Principle: Utilizes temperature differences to generate voltage using the Seebeck effect and materials with different Seebeck coefficients. - Example: Voyager probes use radioisotope thermoelectric generators (RTGs) to convert heat from decaying plutonium into electricity. - Challenges: Low voltage output, requiring boosting circuits for practical use. - Create an oscillator that runs with 50 or 100mV input voltage. *Photovoltaic (**18:15**)* - Principle: Employs the photovoltaic effect in PN junctions to convert photons into electron-hole pairs, generating current and voltage. - Key Considerations: Optimizing power extraction by operating at the right load current and utilizing maximum power point tracking (MPPT) techniques. - Applications: Solar cells for calculators and other small devices. *Piezoelectric (**25:27**)* - Principle: Leverages the piezoelectric effect in materials like gallium nitride to convert mechanical stress and vibrations into AC voltage. - Mechanism: Alignment of polarization domains within the material creates an electric field that changes with applied stress. - Challenges: Rectifying the AC voltage into a usable DC form. *Electromagnetic (**31:45**)* - Near Field Harvesting: Utilizes the inductive near field for efficient energy transfer at close distances, as seen in NFC and Qi charging technologies. - Ambient RF Harvesting: Scavenging energy from ambient radio waves is deemed inefficient due to significant power loss over distance. *Triboelectric (**42:39**)* - Principle: Harvests energy from static electricity generated by friction or contact between materials. - Example: Temperature sensor powered by triboelectric energy harvesting from human motion. - Challenges: Low current output and the need for efficient rectification circuits. *Conclusion (**46:37**)* - No single energy harvesting circuit is universally suitable; the design must be tailored to the specific energy source and application. - Minimizing the average current consumption of electronic circuits is crucial for successful implementation of energy harvesting technologies, especially for batteryless IoT devices. i used gemini 1.5 pro to summarize the transcript

I'm really lucky that I found this channel. Mr. Wulff explains things from fundamental to advanced. It is like a pill for my curiosity on electronics :)

thanks prof

Great tutorial Thanks! To erase a selection in magic you can select an area with the cursor then press e over the layer to be erased.

Wish I could've followed along live with this? Seems like a really good course. Still excited to follow along :)

simply brilliant!