MOS transistor theory

CMOS Inverters and gates

Design a CMOS function implementing Z=ABC+D+EF matching

a standard inverter

.Wires

3

.1 How is capacitance estimated in deep sub-micron? What are the two

components?

3

.2 Calculate the capacitance for a given piece of layout for the HP processs

.3

.3 Calculate the capacitance for a given piece of layout to several layers

.Passive devices

Draw a typical poly-poly capacitor layout

. Why are fingers included?

What are sources of “Stray” capacitance in capacitors

Design a matched set of 3 capacitor with ratios 1, 2, 3

. Show a

layout with all required symmetries to correct for gradients

.Why are diffusion capacitors not often used?

How close can capacitors be matched?

What are 3 common layers used to construct resistors?

Draw a layout example of two matched well resistors of 20k

ohms each

.4

.8 Why are guard rings placed around well and diffusion resistors?

Why are guard rings good around capacitors?

GM related things

What value of Gm should be used to obtain an amplifier with a gain of 10 when RL

is 10k ohms?

What assumptions are made for small signal operation?

Misc

Why is layout important in Mixed signal design?

How are devices matched in Mixed signal design?

Why are device ratios used instead of device values in mixed signal design?

Why must the number of invertors in a ring oscillator be odd?

How can a ring oscillator be started and stopped? What logic elements are added?

PLL

8

.1 Draw the block diagram for a PLL and explain each circuit function

8

.2 Calculate output frequencies from PLL specifications and reference clock rate

.(M/N ratios)

When should an XOR PD be used?

What is Kvco, Kpd and how are they determined?

What is the natural frequency of a PLL?

Current sources and sinks and references

Draw schematics for a current mirror

Why are cascade transistors used?

Design a current reference using a single resistor

Draw the schematic diagram for a band gap voltage

reference

10

.5 How can a band gap voltage reference be used with an external resistor to

provide a precision current reference?

Design a current mirror that will provide 3X the current out vrs

. Current in

.10

.7 How can currents be added and subtracted?

Amplifiers

What conditions must be met for amplifier stability?

Draw schematics for a source coupled pair amplifier

.What is CMRR (CMR) ?

What are the benefits of a current source loaded amplifier?

What is IOS?

What is PSSR?

What is slew rate?

What is an “instrumentation” amplifier? Draw schematics for a typical circuit

Non Linear mixed signal circuits

How can circuits be implemented that perform the ln, exp, square, and square root

functions?

How can ln and exp functions be used to perform multiplication?

How can square law circuits be used to perform multiplication?

What must be done to the length to ensure the transistors approach the square law

curves?

Data converters

Design a switched capacitance D/A

Design a switched capacitance A/D

Design a current mode D/A converter

What is a Thermometer code? How is it important to D/A design?

What is a pipelined A/D converter? Draw a block diagram

.Why are multiple pipelined A/D converters combined?

What voltage could a N bit converter discern if the Vdd is 2

.5V, and N=10?

What is DNL?

What is INL?

What is Gain Error?

What is SNR?

What is ENOB? How is it determined?

What does monotonic increasing mean?

Why are guard rings included in D/A and A/D designs?

What is glitch energy?

I/O Buffers

Draw an ESD circuit

. Explain how it works

.Why are guard rings used in I/O design

. Draw the latch

up devices, and show their origin on a chip view

.Current mode analog

Draw schematics for current mode circuits that add, subtract, multiply, and divide

Draw schematics for a current mode inverter and 2 input NOR gate

Draw schematics for a current mode comparator

Why are cascade devices used in current mode circuits

Why are switched current circuits typically faster than

switched capacitor circuits

How can digital current source matching be implemented? Draw a circuit to illustrate

.Why is current mode analog interesting in future very deep submicron processes? What

fundamental limits can it help overcome?

Switched Capacitor circuits

Draw circuits for a SC resistor equivalent

What is the benefit of a SC resistor over a poly resistor

How can the resistance of a SC resistor be made larger

How can the capacitor size of a given SC resistor value be made smaller

How can a SC resistor be made to have a negative value

What switching rates are typical for a SC circuit?

What is the equation for a simple SC resistor?

How can the frequency response of a SC filter be changed without altering any physical devices?

Draw the circuit for a charge mode integrator and explain how it works

Draw the circuit for a resistive SC amplifier, and explain how it works

How can digital capacitor matching be implemented? Draw schematics of an example to

illustrate