a) Transconductance of bipolar transistors is very high. So with bipolar it is possible to have circuit of very high gain and high gain bandwidth. CMOS designs are limited to low gains.
b) CMOS transistors can work at a lower voltage supply than Bipolar. But by modern technology VT of CMOS have decreased to ~ 0.5 volts. This has brought in several advantages as shown in Table 1.1.
c) Basically CMOS technology is more popular because of the main advantage of high packaging density; and the strengths of CMOS has taken power over it’s weaknesses making it the most popular VLSI technology today.
d) Low power dissipation
e) Small size.
f) High speed.
g) Work at small current.
h) Low cost.
i) Don't effect with temperature.
Table 1.1 Comparison of physical characteristics of bipolar and CMOS-based IBM
S/390 systems.
| ||
ES/9000* 9X2
|
S/390* G6
| |
Technology
|
Bipolar
|
CMOS
|
Total no. of chips
|
5000
|
31
|
Total no. of parts
|
6659
|
92
|
Weight (lb)
|
31,145
|
2057
|
Power requirement (kVA)
|
153
|
5.5
|
Chips per processor
|
390
|
1
|
Maximum memory (GB)
|
10
|
32
|
Space (sq ft)
|
671.6
|
51.9
|
In this project the aim was to design and simulation of electronic circuits for modern wireless and satellite communications with CMOS technology, so we must improve and search what of these categories of Silicon Technology is the best.
In this chapter, we begin with a brief section on the design philosophy of integrated circuits, and how it differs from that of discrete circuits. Throughout this section, MOS is presented side-by-side, which allows a certain economy in presentation and more importantly, provides an opportunity to compare and contrast the types. Toward that end, This section provides a comprehensive comparison of the attributes of the two transistor types. This should serve both as a review as well as a guide to very interesting similarities and differences between the two devices.
