Lecture 8 Transistors and CMOS

1. Lecture 8Transistors and CMOS CSCE 211 Digital Design • Topics • Combinational Circuits Quiz • Structural VHDL • Lab 2 • VHDL: Decoders, Multiplexers • Demultiplexers • Readings 3. September 25, 2003

2. Overview • Last Time • Lab 3 – VHDL • Lab 3 Deliverables: • New • Encoders/Priority Encoders • Transistors • CMOS gates • Review for test • History • Invention of transistor

3. Honors College: Advisement • Appointment Sign-up begins • Wednesday October 1 • 8:00AM • Outside main office 2nd floor Harper • Advisement begins Monday October 6 • CSCE Classes (lower level) • CSCE 145 MW 2:30-3:45 Fuchs • CSCE 146 TTH 9:30-10:45 Bowles • CSCE 212H TTH 12:30-1:45 Matthews • CSCE 240 MWF 9:05-9:55 Fuchs • CSCE 245 MW 4:00-5:15

4. Lab 3 Deliverables • VHDL for 74LS47’ where the ’ means don’t care for 10 … 15 using functions given in class (slide ) • Schematic using components (symbols) made for 74LS47 and 74LS153 (Mux). Add output ports to outputs of 74LS47 and label them with the pin numbers for your seven segment display digit. The input ports should also be labeled. • Circuit for selecting one base-4 number with a mux and displaying it on the even segment display. • You must use the DIP switch to set the input of four base-4 numbers. The select line inputs will be just wires.

5. Hot Batteries • You should regularly check your batteries “slightly warm” is OK but hot indicates that your circuit has a short circuit. • Unplug quickly and check. • Look for direct lines Vcc to GND. • Remember you need 330 ohm resistors in series with LEDs and that includes segments of the seven segment display. • Recheck sections of the breadboard.

6. Functions for 74LS47 with don’t cares • a(D,C,B,A) = D + A.C + A.B + A’.C’ • b(D,C,B,A) = D + (D'*C') + (A'*B') + (A*B) (aj) • c <= a or not b or d (david) • d = • e = A(bar) and (B or C(bar)) (jeremy/patrick) • f = D + A'B' + B'C + A'BC (jon) • g=D + B'C + C'B + A'B (msbell)

7. Karnaugh Map Simplification • On a real 74LS47 the outputs for 10, …15 are not don’t cares. • They would indicate errors in BCD input. We could use the period for that. • period(D,C,B,A)=SUM( ) • dc(D,C,B,A) = SUM( ) C DC 00 01 11 10 BA 00 01 11 10 period(D,C,B,A) = A B D

8. Transistors • History • 1790s Ben Franklin “assigns” negative charge to electrons • 1898 Thompson discovers the electron • 1947 Shockley, Bardeen and Brattain “invent” transistor • 1958 first Integrated Circuit, Texas Instruments • 1971 Intel 4004, microprocessor, Ted Hoff • Timeline • http://www.pbs.org/transistor/

9. Transistor: Water Flow Model Water flow in B raises the plunger so that water can flow from C to E. Small flow turns on and off bigger flow. Put signal on B, transfer signal C to E Reference: http://www.satcure-focus.com/tutor/page4.htm

10. Transistor Terminology • Conductor – electrons easily passed from one atom to next (copper every atom has loose electron) • Insulator – electrons tightly tied down to atoms, no flow • Semiconductor – by adding impurities (doping) can be changed to increase conductivity • Silicon wafer – used for IC circuits • N-type - silicon doped with boron (excess electrons) • P-ype - silicon doped with phosphorous (excess “holes” lack of electrons)

11. Transistor Reference: http://www.intel.com/education/transworks/

12. Transistor Reference: http://www.intel.com/education/transworks/

13. Transistor Put Positive charge on gate. This attracts electrons into gap. This allows electrons to pass freely through the gap. Reference: http://www.intel.com/education/transworks/

14. Transistor Reference: http://www.intel.com/education/transworks/

15. Transistor Take positive charge off Gate This stops attracting electrons. This shuts off the flow. Reference: http://www.intel.com/education/transworks/

16. N channel transitor

17. P channel Transistor

18. CMOS Inverter

19. CMOS NAND

20. What’s This?

21. Test / Sample Test