1. The Zen of Analog Design – A
Preview
March 27, 2013
Because Education should change life...
2. Aims of this seminar
Present a glimpse of the beauty of Analog
Give everyone a small slice of Analog to take back to
your work or study.
To impress upon everyone the importance of Analog
concepts in all domain of electronics & communication.
3. The quest of Analog design …
...An ideal buffer!
VIN VOUT
The output follows the input exactly
exactly.
“Response” matches “stimulus”.
Ideal buffer: VOUT=VIN
4. Another attribute of ideal buffer
VOUT
VIN
ILOAD
Should support any ILOAD.
Ideal buffer: VOUT=VIN for any ILOAD.
5. Analogy with THE most critical facet of human life …
VIN VOUT
Stimulus Response
Eg. Couple has planned
Our Relationships! Is there a *right*
a long overdue vacation Husband-Wife response to this
Parent-Child stimulus?
Husband’s main Friendships What factors will
customer throws an determine how they
urgent request, respond?
Will their *limits* get
tested?
As we will look to realize the ideal buffer, we will get
some insights!
6. Ideal buffer / Healthy relationship
VIN VOUT Stimulus Response
Husband-Wife
Ideal buffer VOUT follows VIN accurately
Healthy relationship able to respond to a stimulus in
the most apt manner
We will elaborate …
7. What is *LOADING* in the human analogy?
Response
Stimulus
Painful prof
Loading Painful boss
Demanding kids
In-laws!
Healthy relationship healthy response to stimulus in
presence of “loading”!
A story will help!
8. To meet the protagonists of our story,
we travel back in time … 3300 years!
The palace of Pharaoh Tutankhamun!
10. Very Large Scale Mummification
Are you sure you
are holding up the
datasheet the right
way?
Aman-Ra has a manager: Gamen-Ra
Every week they have a project review meeting
Gamen-Ra is always suspicious of Aman-Ra
13. 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
14. What is an ideal voltage source?
One that tries to impose a constant voltage at its
output …
… irrespective of the current drawn from it
Io
+
Vs - Circuit
15. What is the I-V curve of an ideal voltage source?
I
Constant voltage for any
current
V
Vs
But we will be using a different element for modeling
relationships.
16. The current source!
What is an ideal current source?
One that forces its current on to a circuit …
… but is capable of taking any voltage across itself
Is
+
Is Vo Circuit
-
17. What is the I-V curve of an ideal current source?
I
Is1 Is2
Is1
Is2
Forces constant current
Capable of taking any voltage
V
Note: Two current sources in series would not find a “meeting
point”
18. How would a *non- ideal* current source look?
I
Is1 Is2
Is2
X
Is1
V
It is possible for two non-ideal current sources in
series to establish a meeting point
19. Now let us create a human analogy...
CURRENT = OUR THINKING/ VIEWS
VOLTAGE = OUR RESPONSE TO A STIMULUS
Your
You views
Our combined response to a
stimulus
Me My
views
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!
The need to always “be right” makes us like a current source!
20. We revisit Aman-Ra and Woman-Ra
They meet each other and fall in love...
X
A perfect *Operating point* gets established!
21. What is a“perfect operating point”?
Even a “perfect” relationship has limits on the range of
stimulus!
In our buffer analogy, this was…
VDD
VIN VOUT
GND
22. We can visualize these bounds as:
Ideal
“operating
point”
The margin for The margin for
VOUT when VOUT when
VIN reduces VIN increases
V
GND VDD
Similar concept for a relationship!
“Headroom” in Analog parlance
23. To see how the story continues…
Visit www.sahyogee.com/zen
