---
title: "Three major IC technologies"
subject: "Embedded System"
chapter: 8
key: "semester_6/embedded_system:three-major-ic-technologies"
source: https://www.bctengineer.com/q/semester_6/embedded_system/three-major-ic-technologies
site: BCT Engineering
---

# Three major IC technologies

Embedded System · Chapter 8: IC Technology

- Asked in: 2070 Magh, 3 marks
- Video: [IC Technology -- Embedded System Design](https://www.youtube.com/watch?v=ljaDbVxTyPo) — Roy Knowledge
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/embedded_system/three-major-ic-technologies
- Whole chapter: https://www.bctengineer.com/md/semester_6/embedded_system/chapter-8

## Question

List the three major IC technologies with brief definitions.

## Short answer

Full-custom: every transistor and interconnect designed custom for best performance/area, high NRE cost. Semi-custom: uses standard cells or gate arrays, balancing cost and time. Programmable logic (PLD/FPGA): pre-fabricated, user-programmed, no custom masks.

## Answer

1. **Full-custom (VLSI) IC technology:** every transistor and wire of the chip is designed and laid out specially, and all masks are custom. It gives the best performance, power and area, but is expensive and slow to design; used for high-volume chips like processors.
2. **Semi-custom (ASIC) IC technology:** the chip uses pre-designed cells or pre-fabricated transistor arrays (standard cell, gate array); only part of the layout (placement and routing, some masks) is customised. It is a compromise between cost, time and performance.
3. **Programmable logic device (PLD) technology:** a standard, pre-fabricated chip (PAL, CPLD, FPGA) whose logic and connections are programmed by the user after manufacture, with no custom masks. It has the lowest design cost and time and can be reprogrammed.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What defines full-custom IC technology?
   A. The user programs it after manufacture
   B. Only the metal masks are custom
   C. Every transistor and wire is designed specially and all masks are custom
   D. It uses only standard cells
   Answer: C. Full custom designs every transistor and wire with custom masks for best performance but high cost. (Key point: Full-custom)

2. In semi-custom (ASIC) technology, what is customised?
   A. Only part of the layout such as placement, routing or some masks, using pre-designed cells or arrays
   B. Every transistor shape
   C. Nothing at all
   D. Only the package
   Answer: A. Pre-designed cells or pre-fabricated arrays are used and only placement/routing are customised. (Key point: Semi-custom)

3. What is the key feature of programmable logic device technology?
   A. It needs custom masks for each design
   B. It cannot be changed
   C. It has the best power and area
   D. A standard pre-fabricated chip is programmed by the user after manufacture
   Answer: D. PLDs (PAL, CPLD, FPGA) are programmed after manufacture, so no custom masks and the lowest design cost. (Key point: PLD)

4. Which technology has the best performance but highest cost and slowest design?
   A. PLD
   B. Full-custom
   C. Semi-custom
   D. Gate array
   Answer: B. Full custom gives best performance, power and area but is expensive and slow to design. (Key point: Trade-off)

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