The Gateway to Computer Science Excellence
0 votes
How many gate delays are there in overflow for ripple carry adder?
in Digital Logic by (25 points) | 293 views

what's the given answer ?
it's confusing. at some places it is given 2n+1 and at other 2n+2

1 Answer

+4 votes
Best answer
If LSB also uses FULL Adder,(we can use Half Adder for LSB because we don't need carry-in).

For the first carry out, there will be 3 GATE DELAY: 1 AND, 1 EX-OR, 1 OR

For the next (n-1) bit , only 2 Gate Delay will be considered: 1 OR and 1 AND because EX-OR Operation will happen at parallel.


So total gate delay will be = 2*(n-1) + 3 = 2n+1 Gate Delay
by Active (3.1k points)
selected by


I considered XOR Gate as 1 Gate Delay, if we consider 2 Gate Delay for XOR GATE, in that case it'll be 2n+2.

the link you posted has considered 2 Gate Delay for XOR Gate 

can you provide me a good resource for this concept ??

in this pdf, they've considered NAND Gate implementation, it should help you with the idea.


thank you Aakash

Quick search syntax
tags tag:apple
author user:martin
title title:apple
content content:apple
exclude -tag:apple
force match +apple
views views:100
score score:10
answers answers:2
is accepted isaccepted:true
is closed isclosed:true
50,737 questions
57,352 answers
105,245 users