Digital Electronics
Unit 2.1.5 – AOI Logic Implementation
This presentation will demonstrate how to:
1) Design an AOI logic circuit from a ____________________________ (______) logic expression.
2) Design an AOI logic circuit from a ____________________________ (______) logic expression.
Sum-Of-Products (SOP)
____________________________ is one of two ways to create a logic expression.
A _________________________, in SOP form, shows _______________________________________
that produce a logic “___” output.
These combinations of input variables are known as _______________.
In a Sum-of-Products expression the Minterms are ________________ (________) together.
SOP expressions can easily be implemented as a set of _______ gates feeding into a single ______ gate.
Example:
F2  A B C D  B C D  A B
Designing AOI SOP Logic Circuits
Three (3) Design Steps
1) Implement each Minterm in the logic expression with an _________ gate with the __________
________________ of inputs as there are variables in the Minterm.
(i.e., AB = ____ input gate, ABC = ____ input gate,
ABCD = ____ input gate, etc.)
2) ______ together the outputs of the AND gates to produce the logic expression.
3) If necessary, gates can be __________________ to create gates with more inputs.
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Example #1: AOI Implementation SOP
Design an AOI Logic Circuit for the SOP logic expression shown below.
F2  A B C D  B C D  A B
Solution:
F2  A B C D  B C D  A B
Unfortunately, in this class, we only have access to (2) input OR gates and (2) & (3) input AND gates.
Limiting your design to these gates, ______________ the AOI Logic Circuit for the SOP expression in
the previous example.
Example #2: AOI Implementation SOP
Solution: Redesigned using 2-3 input gates only.
Product-Of-Sums (POS)
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Product-of-Sums (POS)
__________________________ (_______) is another way to create a logic expression.
A __________________________, in _______ form, is the _________________ of the _______ form.
A logic expression, in POS form, shows _______________________________________ that produce a
logic “___” output.
These combinations of input variables are known as ________________.
In a Product-Of-Sums expression, the Maxterms are ______________ (___________) together.
POS expressions can be implemented as a set of ______ gates feeding into a single _______ gate.
Example:



F4  W  X  Y  Z W  X  Y W  Z

Designing AOI POS Logic Circuits
Three (3) Design Steps
1. Implement each _____________ in the logic expression with an ______ gate with the same number of
____________ as there are variables in the Maxterm.
(i.e., A+B = 2 input gate, A+B+C = 3 input gate, A+B+C+D = 4 input gate, etc.)
2. __________ together the outputs of the OR gates to produce the logic expression.
3. If necessary, gates can be ________________ to create gates with more inputs.
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Example #3: AOI Implementation POS
Design an AOI Logic Circuit for the POS logic expression shown below:



F4  W  X  Y  Z W  X  Y W  Z

Solution
Example #4: AOI Implementation POS
Limiting your design to only (___) input ______ gates and _______ input ________ gates, redesign the
AOI Logic Circuit for the POS logic expression in the previous example.
Solution
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