EECS 40 Introduction to Microelectronic Circuits

Course Focus The analog circuits that drive digital devices: v out v in V DD A  CMOS Inverter Circuit Inverter Logic Symbol

How to Succeed Complete and understand homework –Copy ≠ Complete Work along with GSI in discussion Pay attention in class –Listen, ponder, work along –Don’t just be a scribe

Course Focus The analog circuits that drive digital devices: v out v in V DD A  CMOS Inverter Circuit Inverter Logic Symbol

Digital Systems Information is represented numerically Computers –Add, subtract, move numbers around Digital Communications –Encoded sequences represent conversations, fly through the air

Number Representation Mathematical: Binary numbers –Instead of powers of 10, use powers of 2 – 5 becomes 101 (1 x x x 2 0 ) Physical: 1’s and 0’s are voltages – e. g., 3 volts represents “1”, 0 volts for “0” –1’s and 0’s encoded different ways for transmission (optical, other electromagnetic) which generates voltage at receiver

Digital Advantages Digital Communication –Digital representation makes encoding and processing easier –Reconstruct signal to arbitrary accuracy (need bandwidth) Computers –Arbitrary computational accuracy, just add more significant figures (big floating-point unit) –Can store information with arbitrary accuracy (big memory)

Digital Computation Logic gates manipulate voltages to perform operations on the binary numbers v out v in V DD CMOS Inverter Circuit A voltage, 3 volts representing 1 for example, is applied to input The “opposite” voltage, 0 volts in this case, appears at output

Logic Gates A B C=A·B AND C = NOR A B NOT A OR A B C=A+B EXCLUSIVE OR A B A B

Logical Functions “AND” “OR” “INVERT” or “NOT” “not AND” = NAND “not OR” = NOR exclusive OR = XOR A or A not Opposite of A