ICs
What components do digital ICs contain?
A single IC could contain thousands or millions of:
- transistors
- resistors
- capacitors
- diodes
Elaborate the term unit load.
Fanout is specified in terms of unit loads. A unit load for a logic gate equals one input to a similar circuit. For example, a unit load for a 7400 NAND gate equals one input to another logic in the standard 7400 series (not necessarily a NAND gate).
Unit loads (Fan out) = IOH / IIH = IOL / IIL = 400 ????A/40????A = 16 mA/1.6 mA
A standard 74 series TTC gate can drive 10 unit loads. Most of the other TTL series, such as the LS can drive 20 unit loads.
What is the difference between an analog IC and Digital IC?
- Analog ICs accept and output analog data through its pins whereas digital ICs deal with only logic data inputs and outputs.
- Almost every analog IC requires external components for its functioning whereas digital ICs don’t require external components.
- Ex. IC555 is analog IC and trigger pin is given variable input which is accepted by IC for dedicated application. On other hand, digital IC like 7404 which is a NOT gate with TTL logic level works only in voltage range of 0–0.8V and 2–5V only.
What is propagation delay?
Propagation delay is defined as the time taken for the output of a gate to change after the inputs have changed.
What are the functions of integrated circuits?
A tiny chip known as an integrated circuit serves as a microprocessor, oscillator, amplifier, or computer memory.
Characteristics of Digital ICs
Digital circuits are constructed by using different logic gates, so when we use different ICs, we have to produce different logic gates using different technologies. For the fabrication of ICs, we use semiconductor devices-bipolar and unipolar. Based on the devices, digital ICs are made which are then commercially available. When we use a bipolar device, like a transistor in the IC fabrication technology, it is known as bipolar technology. In unipolar technology, we make use of unipolar devices. e.g., MOSFETs. A group of compatible ICs with the same logic level and supply voltages for performing various logic functions which have been fabricated using specified configuration, is referred to as a logic family.
Table of Content
- Integrated Circuits
- Classification
- Characteristics
- Features
- Advantages
- Disadvantages
- Applications