MOSFET vs. bipolar in integrated circuits: What is the principal advantage of using MOS technology over bipolar circuitry for large ICs?
-
Amuch greater complexity (more components) than bipolar circuits : better economy
-
Bhigher operating speed than bipolar circuits
-
Cfewer power supply connections are required with MOS ICs
-
Dsystem designers are more familiar with MOS circuitry
-
Elower static power and very high density enabling LSI/VLSI integration
Answer
Correct Answer: much greater complexity (more components) than bipolar circuits : better economy
Explanation
Introduction / Context:Choosing a device technology affects density, power, and cost. MOSFET-based integrated circuits, especially CMOS, enable extremely high transistor counts with low static power, making them ideal for large-scale and very-large-scale integration (LSI/VLSI). Historically, this has been the decisive advantage over bipolar logic families for large chips.
Given Data / Assumptions:
- We are comparing mainstream advantages in IC manufacturing.
- “Complexity” here means achievable transistor count per chip (density).
- Bipolar circuits tend to consume more static power and scale poorly in density.
Concept / Approach:MOS processes permit tiny, low-leakage transistors and complementary logic (CMOS) with near-zero static power, enabling dense logic with acceptable thermal profiles. Consequently, designers can implement much greater functional complexity on a single die at better cost per function than with bipolar processes for large designs.
Step-by-Step Solution:Identify the core differentiator: density and static power.Relate density to achievable complexity and cost per function.Conclude that MOS's advantage is supporting much greater complexity → better economy.
Verification / Alternative check:The universal adoption of CMOS for microprocessors, SoCs, and memory underscores MOS's density/cost advantages, even though bipolar (e.g., ECL) may offer higher raw speed in niche cases.
Why Other Options Are Wrong:Higher operating speed (b) is generally a bipolar advantage, not MOS's. Fewer supply connections (c) is not the fundamental driver. Familiarity (d) is not a technology advantage. (e) restates the density/power idea but the keyed correct choice in this item is the complexity/economy phrasing.
Common Pitfalls:Equating “faster” with “better” for all contexts; for LSI/VLSI, power and density win.
Final Answer:much greater complexity (more components) than bipolar circuits : better economy