Author Archives: Dai

My Circle is Like a Smith Chart

Smith chart is used be mysterious to me. My daughter has an interesting book named my heart is like a zoo. This makes me come up with the story – my circle is like a Smith chart. I can find … Continue reading

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Current-Mode-Logic (CML) Latch

It’s a rather old topic and one can find many good references. In this post, I will write down some of my basic understandings on this circuit. Operation of CML latch Figure 1 shows a simplified block diagram of divider-by-2 … Continue reading

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[M scripts] Speed estimation of CML latch

The Matlab script used in this post:

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100 Keywords – Doping

Doping is a technique used to modify the density of charge carriers in semiconductors. A small section of the periodic table is copied as follows. Boron is a “Group 3” element. It has 3 valence electrons in its outmost shell. … Continue reading

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100 Keywords – Holes

In reality, there are no holes! It just refers to positive charge. The diagram below shows positive charge travels from the left to the right of silicon. At t1, one electron is released which produces a positive charge (indicated as … Continue reading

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100 Keywords – Silicon

A silicon atom has 14 electrons. In its outmost shell, it has 4 valence electrons. Covalent bonding in silicon: Its resistivity drops as temperature rises. Density of free electrons in silicon can be calculated as: At T=300K,  In the same … Continue reading

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100 Keywords – Preface

Feng Tang once said that if you want to know a bit about a new field, go and find 100 keywords. Digest them in two or three days, and you will look like a professional. Somewhat make sense! This triggers … Continue reading

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CMOS Single Stage

Found an old drawing on CMOS single stage from many years ago.  Stay healthy!

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Basics On Active-RC Low-Pass Filters

Just some basic understandings on analog filters which is inspired by ‘The Guru’ in our company. To clarify my thoughts, I will write in the format of Q&A. There are four questions to answer: What do we dream for a … Continue reading

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Leading Simulators for Analog/RF Circuits

Recently I have the opportunity to touch some RF design. WoW, some simple metal lines need a fancy tool to get them modeled! WoW, both Windows and Unix tools are involved to simulate the EVM! It seems that Cadence Spectre … Continue reading

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