Digital Electronics And Logic Design

  What is a Logic Family? In Digital Designs, our primary aim is to create an Integrated Circuit (IC). A Circuit configuration or arrangement of the circuit elements in a special manner will result in a particular Logic Family. What are the advantages of creating different Logic Families? Electrical Characteristics of the  IC will be identical. In other words, the different parameters like Noise Margin, Fan In, Fan Out etc will be identical. Different ICs belonging to the same logic families will be compatible with each other. Some Characteristics we consider for the selection of a particular Logic Family are: Supply voltage range  Speed of response  Power dissipation  Input and output logic levels  Current sourcing and sinking capability Fan-out  Noise margin The basic Classification of the Logic Families are as follows: Bipolar Devices MOS Devices Hybrid Devices  Bipolar Families: Diode Logic (DL) Resistor Transistor Logic (RTL) Diode Transistor Logic (DTL) Transistor- Transistor Log

  5 variable K-Map in Digital Logic Karnaugh Map  or K-Map is an alternative way to write truth table and is used for the simplification of Boolean Expressions. So far we are familiar with 3 variable K-Map & 4 variable K-Map. Now, let us discuss the 5-variable K-Map in detail. Any Boolean Expression or Function comprising of 5 variables can be solved using the 5 variable K-Map. Such a 5 variable K-Map must contain   = 32 cells . Let the 5-variable Boolean function be represented as : f ( P Q R S T)  where P, Q, R, S, T are the variables and P is the most significant bit variable and T is the least significant bit variable. The structure of such a K-Map for SOP expression is given below : The cell no. written corresponding to each cell can be understood from the example described here: Here for variable  P=0, we have Q = 0, R = 1, S = 1, T = 1 i.e. (PQRST)=(00111)  . In decimal form, this is equivalent to  7 . So, for the cell shown above the corresponding cell no. = 7. In a similar