Question

The advantage of Multi-emitter transistor is

(a) To reduce fabrication steps

(b) To save chip area

(c) To lower design consideration

(d) To provide linear output

The question was posed to me in homework.

I need to ask this question from Active and Passive Components of IC in section IC Fabrication of Linear Integrated Circuits

Answer 1

The correct answer is:

(b) To save chip area

Explanation:

Multi-emitter transistors are commonly used in digital integrated circuits, especially in TTL (Transistor-Transistor Logic). Their primary advantage is that they allow multiple input signals to share the same transistor, reducing the need for separate transistors for each input. This helps in:

1. Saving chip area: By integrating multiple emitters into a single transistor, the overall space required for the circuit is minimized.
2. Enabling efficient logic gate design (e.g., NAND gates).
3. Simplifying circuit layouts for complex logic functions.

Why not the other options?

• (a) To reduce fabrication steps: Multi-emitter transistors may increase fabrication complexity due to additional masking steps for multiple emitters.
• (c) To lower design consideration: Multi-emitter transistors are introduced for functionality, not necessarily to simplify design requirements.
• (d) To provide linear output: They are not used for linear applications but for switching purposes in logic circuits.