ECE 275: Digital Design I
Class 4
- SSI - Small Scale Integration (~50 transistors) - Logic gates
- MSI - Medium Scale Integration (50-500 transistors) - Flip Flops
- LSI - Large Scale Integration (500-50K) - Larger memory components
- VLSI - Very Large Scale Integration (500,000) - Processors Cache
Gordon Moore (Moore's Law)
Double the amount of transistors in the same chip area over ~18 months
IC Logic Families
- RTL - Resistor Transistor Logic
- DTL - Diode Transistor Logic
- TTL - Transistor Transistor Logic
- ECL - Emitter Coupled Logic (BJT)
- NMOS - N-Type Metal Oxide Semiconductor (MOS)
- PMOS - P-Type MOS
- CMOS - Complementory MOS - Modern devices use this
Characteristics
- Fan Out - How many gates can the output drive? Buffer = Not gate without the not. Given 1, it outputs 1. Given 0, it outputs 0 Buffer has a fan out of 50-70 gates
- Propagation Delay - How long the gate takes to change after updating the input Usually in the order of picoseconds
TTL | ECL | CMOS | |
---|---|---|---|
Fan Out | 1-10 | 20-30 | 750 |
PD | 1-3ons | 1-6ns | 1-210ns |
Power | 10nW | 50mW | 0.01mW |