2. INTRODUCTION
ICs are integrated using following integration
techniques
•SSI < 12 gates/chip
•MSI < 100 gates/chip
•LSI …1K gates/chip
•VLSI …10K gates/chip
•ULSI …100K gates/chip
3. Logic Family
It is a group of compatible ICs with the same
logic levels and the supply voltages for
performing various logic functions
They are the building block of logic circuits.
5. BIPOLAR ICs
The main element of a bipolar ICs are
Resistors, Diodes, Capacitors and Transistors.
They can be operated in two ways:
Saturated
Non-Saturated
Saturated Logic: The transistors in the IC are
driven to saturation
Non-Saturated Logic: The transistors in the IC
are not driven to saturation.
7. UNIPOLAR LOGIC FAMILIES
MOS devices are unipolar devices and only
MOSFETs are employed in MOS logic circuits.
These families are:
PMOS (p-channel MOSFETs)
NMOS (n-channel MOSFETs)
CMOS (Both p- and n- channel MOSFETs are
fabricated on same silicon chip)
8. Basic Characteristics of ICs
Propagation delay
Power dissipation
Fan in and fan out
Noise immunity
Power supply requirement
Figure of merits i.e. speed power product
Operating temperature
Current and voltage parameters
9. Power supply requirement
CMOS and TTL are available in different supply
voltage categories
In each IC, Vcc pin is connected to positive supply
and GND pin is connected to ground of supply.
10. Current and voltage parameters
Four different kind of Logic level specifications
are defined: VIL, VIH, VOL, VOH
VIL, VIH : These are the input logic levels (Low &
High)
VOL, VOH : These are the output logic levels (Low &
High)
11. Noise Immunity
Noise is unwanted voltage that is induced in
electrical circuits and can cause threat to
proper operation of circuit.
Noise immunity is the ability to tolerate a
certain amount of unwanted voltage
fluctuations on its inputs without changing
outputs
12. Noise Margin
A quantitative measure of noise immunity is
called Noise margin. It is expressed in volts.
Two Noise margins are specified for logic circuits,
High level Noise margin (VNH) and Low level Noise
margin (VNL), expressed as:
13. Power Dissipation
This is the amount of power dissipated in an
IC.
It is Determined by the current Icc, that it
draws from the Vcc supply, and is given by ,
Pd = Vcc X Icc.
15. Fan in and Fan out
Fan-in:
Number of inputs a gate has. For example, a two
input gate will have fan-in equal to 2
Fan-out:
Maximum number of inputs of the same IC
family that a gate can drive without falling
outside the specified output voltage limits.
16. Figure of merits/speed power product
This is obtained by multiplying gate
propagation delay by gate power
dissipation
17. Operating temperature
For consumer application , the temperature is
0 to +70°C
For industrial application , the temperature is
-55°C to +125 °C
27. CMOS-Complementary metal oxide
semiconductor
most widely used family for large-scale devices
combines high speed with low power consumption
usually operates from a single supply of 5 – 15 V
excellent noise immunity of about 30% of supply
voltage
28. CMOS inverter
A Q1 Q2 O/P
0V
(Logic 0)
OFF ON VDD
(Logic 1)
VDD
(Logic 1)
ON OFF 0V
(Logic 0)
29. CMOS NAND gate
Input Transistor O/
P
A B Q1 Q2 Q3 Q4 Y
0 0 ON ON OFF OFF 1
0 1 ON OFF OFF ON 1
1 0 OFF ON ON OFF 1
1 1 OFF OFF ON ON 0
