Logic Families – Notes – 1

Electronics Engineering » Notes » Logic Families

1. Digital or logic circuits operate on voltages that fall in prescribed ranges that represent either a binary 0 or a binary 1.

2. All digital logic devices are similar in nature but very much different regarding the details of their characteristics. An understanding of the terms used to describe these characteristics is important and allows us to compare and contrast the performance of devices. By understanding the capabilities and limitations of each type of device, we can intelligently combine devices to take advantage of each device’s strengths in building reliable digital systems.

3. The TTL family of logic devices has been in use for over 30 years.The circuitry uses bipolar transistors. This family offers many SSI logic gates, and MSI devices. Numerous series of similarly numbered devices have been developed because advances in technology have offered improved characteristics.

4. When you are connecting devices together, it is vital to know how many inputs a given output can drive without compromising reliability. This is referred to as fan-out.

5. Open-collector and open-drain outputs can be wired together to implement a wired-AND function. Tristate outputs can be wired together to allow numerous devices to share a common data path known as a bus.In such a case, only one device is allowed to assert a logic level on the bus (i.e., drive the bus) at any one time.

6. The fastest logic devices are from a family that uses emitter-coupled logic (ECL). This technology also uses bipolar transistors but is not as widely used as TTL due to inconvenient input/output characteristics.

7. MOSFET transistors can also be used to implement logic functions. The main advantage of MOS logic is lower power and greater packing density.

8. The use of complementary MOSFETs has produced CMOS logic families. CMOS technology has captured the market due to its very low power and competitive speed.

9. The ongoing need to reduce power and size has led to several new series of devices that operate on 3.3 V and 2.5 V.

10. Logic devices that use various technologies cannot always be directly connected together and operate reliably. The voltage and current characteristics of inputs and outputs must be considered and precautions taken to ensure proper operation.

11. CMOS technology allows a digital system to control analog switches called transmission gates.These devices can pass or block an analog signal, depending on the digital logic level that controls it.

12. Analog voltage comparators offer another bridge between analog signals and digital systems.These devices compare analog voltages and output a digital logic level based on which voltage is greater.They allow an analog system to control a digital system.

Subject Name : Electronics Engineering
Exam Name : IIT GATE, UPSC ESE, RRB, SSC, DMRC, NMRC, BSNL, DRDO, ISRO, BARC, NIELIT
Posts Name : Assistant Engineer, Management Trainee, Junior Engineer, Technical Assistant
Electronics & Communication Engineering Books

Sale
Question Bank On Electronics & Communication Engineering
Book - question bank on electronics & communication engineering; Language: english; Binding: paperback
₹ 346
Sale
A Handbook for Electronics Engineering(Old Edition)
Made Easy Editorial Board (Author); Marathi (Publication Language); 620 Pages - 01/01/2015 (Publication Date) - Made Easy Publications (Publisher)
₹ 195
Sale
Basic Electronic Devices and Circuits
Patil (Author); English (Publication Language)
₹ 383
Sale
Electronic Circuits: Analysis and Design (SIE) | 3rd Edition
Neamen, Donald (Author); English (Publication Language); 1351 Pages - 08/25/2006 (Publication Date) - McGraw Hill Education (Publisher)
₹ 460

GATE 2022 Total InfoENGG DIPLOMAUGC NET Total Info
IES 2022 Total InfoPSUs 2021 Total InfoCSIR UGC NET Total Info
JAM 2022 Total InfoM TECH 2021 Total InfoRAILWAY 2021 Total Info

Related Posts

  • Programmable Logic Devices - 1155555555555115. Most complex digital designs include ________. (a) standard logic devices (b) ASIC devices (c) microprocessor/DSP devices (d) a mix of different hardware categories
    Tags: devices, logic, digital, electronics, engineering
  • Programmable Logic Devices - 21555555555521. What is another name for digital circuitry called sequential logic? (a) logic macrocell (b) logic array (c) flip-flop memory circuitry (d) inverter
    Tags: logic, devices, digital, electronics, engineering
  • Programmable Logic Devices - 85555555555585. Which is a major digital system category? (a) Standard logic devices (b) ASICs (c) Microprocessor/DSP devices (d) All of the above
    Tags: devices, logic, digital, electronics, engineering
  • Programmable Logic Devices - 1165555555555116. Using a hardware solution for a digital system is always ________ than a software solution. (a) slower (b) harder (c) easier (d) faster
    Tags: logic, devices, digital, electronics, engineering
  • Programmable Logic Devices - 75555555555575. What programmable technology is used in FPGA devices? (a) SRAM (b) FLASH (c) Antifuse (d) All of the above
    Tags: devices, logic, technology, electronics, engineering

LEAVE A REPLY

Please enter your comment!
Please enter your name here