The zen of_analog_design_preview

The Zen of Analog The Zen of Analog The Zen of Analog The Zen of Analog Design Design Design Design –––– A A A A PreviewPreviewPreviewPreview

March 27, 2013

Because Education should change life...

� Give everyone a small slice of Analog to take back to your work or study.

� Present a glimpse of the beauty of Analog

� To impress upon everyone the importance of Analog concepts in all domain of electronics & communication.

Aims of this seminar

The quest of Analog design …

VOUT VIN

The output follows the input exactlyexactlyexactlyexactly.

“Response” matches “stimulus”.

...An ideal buffer!...An ideal buffer!...An ideal buffer!...An ideal buffer!

Ideal buffer: VOUT=VIN

Another attribute of ideal buffer

VOUT VIN

Should support any ILOAD.

ILOAD

Ideal buffer: VOUT=VIN for any ILOAD.

Analogy with THE most critical facet of human life …

Response Stimulus

Our Relationships!

Husband-Wife

Parent-Child

As we will look to realize the ideal buffer, we will get some insights!

Friendships

Eg. Couple has planned a long overdue vacation �

Is there a *right* response to this stimulus?

What factors will determine how they respond?

VIN VOUT

� Husband’s main customer throws an urgent request,

Will their *limits* get tested?

VOUT VIN Response Stimulus

Husband-Wife

Healthy relationship � able to respond to a stimulus in the most apt manner

We will elaborate …

Ideal buffer / Healthy relationship

Ideal buffer � VOUT follows VIN accurately

What is *LOADING* in the human analogy?

Response Stimulus

Loading Painful boss

Demanding kids

Healthy relationship � healthy response to stimulus in presence of “loading”!

In-laws!

Painful prof

A story will help!A story will help!A story will help!A story will help!

we travel back in time …

3300 years!

The palace of Pharaoh Tutankhamun!

To meet the protagonists of our story,

Aman-Ra

Design lead in the VLSM industry

Very Large Scale Mummification

Aman-Ra has a manager: Gamen-Ra

Gamen-Ra is always suspicious of Aman-Ra Every week they have a project review meeting

Are you sure you are holding up the datasheet the right

way?

Woman-Ra

CFO to the Pharoah’s wife

Chief Fan Operator

We will visit their story soon...

But first we will look to pick up the language of Analog design!

Let’s start with ABC …

… The Voltage source

What is an ideal voltage source?

One that tries to impose a constant voltage at its output …

… irrespective of the current drawn from it

+ - Circuit Vs

Io

What is the I-V curve of an ideal voltage source?

V

I

Vs

Constant voltage for any current

But we will be using a different element for modeling relationships.

What is an ideal current source?

One that forces its current on to a circuit …

… but is capable of taking any voltage across itself

Circuit Is Vo

+

-

The current source!

Is

What is the I-V curve of an ideal current source?

V

Is1

I

Forces constant current Capable of taking any voltage

Is1 Is2

Is2

Note: Two current sources in series would not find a “meeting point”

How would a *non- ideal* current source look?

V

Is1

I

It is possible for two non-ideal current sources in series to establish a meeting point

X

Is1 Is2 Is2

Now let us create a human analogy...

CURRENT = OUR THINKING/ VIEWSCURRENT = OUR THINKING/ VIEWSCURRENT = OUR THINKING/ VIEWSCURRENT = OUR THINKING/ VIEWS

VOLTAGE = OUR RESPONSE TO A STIMULUSVOLTAGE = OUR RESPONSE TO A STIMULUSVOLTAGE = OUR RESPONSE TO A STIMULUSVOLTAGE = OUR RESPONSE TO A STIMULUS

Me

You

My views

Your views

Our combined response to a stimulus

The fascinating thing about humans is that we are capable of almost any response to a stimulus...

As long as we get to impose our views!As long as we get to impose our views!As long as we get to impose our views!As long as we get to impose our views!

The need to always “be right” makes us like a current source!The need to always “be right” makes us like a current source!The need to always “be right” makes us like a current source!The need to always “be right” makes us like a current source!

We revisit Aman-Ra and Woman-Ra

They meet each other and fall in love...

XXXX

A perfect *Operating point* gets established!

What is a“perfect operating point”?

Even a “perfect” relationship has limits on the range of stimulus!

VOUT VIN

VDDVDDVDDVDD

GNDGNDGNDGND

In our buffer analogy, this was…

We can visualize these bounds as:

V VDD GND

Ideal “operating point”

The margin for VOUT when VIN reduces

The margin for VOUT when VIN increases

“Headroom” in Analog parlance

Similar concept for a relationship!

To see how the story continues… Visit www.sahyogee.com/zen