Addition Time for a Basic Ripple-Carry Adder

Let tgate = the propogation delay through a typical logic gate

Half adder propagation delays

tadd = 3 tgate

tcarry = 2 tgate

Full adder propagation delays

tadd = 3 tgate

tcarry = 2 tgate

Ripple-Carry Adder (n-bits)

tadd = (n - 1)2 tgate + 3 tgate

= (2n + 1) tgate

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