why totem pole outputs cannot be connected together

If you examine a typical circuit board today you will find more use of large ICs with hundreds of pins and fewer Reference: Understanding Computers, Time-Life Books. LSI - Large scale integration - >1000 transistors (100 to 3000 gates)ġ971 - Intel 4004 microprocessor, with 2,250 transistors.ġ978 - VLSI - Very large scale integration, >10,000 transistors (1000 - 30,000 gates)ġ979 - Motorola 68000 microprocessor, 70,000 transistors.ġ985 - ASICs (application-specific ICs) appear with >100,000 gates.ġ995 - CPU, memory functions available in ASICs with >1 million gates. MSI - Medium scale integration - >100 transistors (10 to 300 gates) SSI - Small scale integration - >10 transistors (1 to 30 gates) It would be instructive to look at a chronology of computer electronics.ġ906 - Vacuum tube invented by Lee De Forest.ġ946 - The ENIAC digital computer built, 18 feet high x 80 feet long, with 17,000ġ947 - Transistor invented by William Shockley.ġ955-1965 - Discrete transistor usage increases.ġ958 - Integrated circuit invented by Jack Kilby. In order to put into perspective where the above devices fit into the scheme of things and how far we have come, Sub-families with their characteristics and designations The following table is a growing list of various TheĬhart shows the speed-power relationship of common TTL families.ĭigital IC manufacturers are continually trying to minimize the delay-power product and continue to produceįamilies with different characteristics to suit specific needs. Families can be characterized by the relationship between propagation-delay and power. These two tend to be directly related, i.e., higher speedĬonsumes more power. Of each logic family are speed and power consumption. Two important factors in the consideration Many second-generation families, each with different operating characteristics.

Technology which exhibits low power and high noise immunity. Another common structure is CMOS ( complementary metal-oxide-silicon) A common structure is the bipolar transistor/transitor logic (TTL) which you willīe using in the laboratory. Problem 10 - Open-collector and tri-stateĭigital logic is implemented using integrated circuits which are classified into families based on their basicĮlectronic structure.

Objectives: To present basic characteristic and limitations of gates. 4D6 Lab Manual - Chapter 6 Chapter 6 Gate Characteristics

Why totem pole outputs cannot be connected together