Slide 1 1 Lecture DIGITAL SYSTEMS Nguyen Thanh Hai, PhD Chapter 5 Integrated Circuits University of Technical Education Faculty of Electrical & Electronic Engineering University of Technology and Educ[.]
University of Technical Education Faculty of Electrical & Electronic Engineering Lecture: DIGITAL SYSTEMS Chapter 5: Integrated Circuits Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits 5.1 5.2 5.3 5.4 5.5 5.6 5.7 TTL and CMOS Families Data sheet The loading and the Fan-out Open-Collector/Open-Drain Outputs Tristate (Three-State) Logic Outputs TTL Driving CMOS CMOS Driving TTL Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits Open-Collector/Open-Drain Outputs Rp is connected outside Rp (external) V0 Q3 ON V0 = VOL ≤ 0.4 V Q3 OFF V0 = VOL = +5 V Nguyen Thanh Hai, PhD V0 at the output Rp = 10k is small enough for the minimum below VOH and IOL(max) University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits Open-Collector/Open-Drain Outputs Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits Open-Collector/Open-Drain Outputs 5 V A B C A B C 74LS05 (open -collector) or 74HC05 (open -drain) 10 k Output A B C Symbolizes the wired-AND connection (AND gate with inputs -Only pulling outputs LOW -Sharing the same wire for transmitting in a logic level Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits 24 V 74LS112 J 7406 Q CLK K 24 V, 25 mA V0 Q Transistor shown for illustrative purposes Example: -7406 buffer between FF and Lamp -Lamp acting as the pull-up resistor for the open-collector output -Q = 1, the lamp is on and otherwise Q = 0, it is off Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits 5 V Rs 74HCT74 7406 Q D CLK Q Example: -In this case, 7406 open-collector output is to drive an indicator LED -The resistor Rs is for limiting the current -For example of some series and parallel resistors/Leds Nguyen Thanh Hai, PhD University of Technology and Education Faculty of Electrical & Electronic Engineering Integrated Circuits The End Nguyen Thanh Hai, PhD