Ternary and Quaternary CNTFET Full Adders are less efficient than the Binary Ones for Carry-Propagate Adders

TL;DR

This paper compares the efficiency of ternary and quaternary CNTFET full adders with binary ones in carry-propagate adders, showing that binary adders are more efficient due to lower propagation delays.

Contribution

It introduces ternary and quaternary CNTFET full adders with different carry-in voltages and compares their performance to binary adders in carry-propagate architectures.

Findings

Binary adders have lower propagation delays than ternary and quaternary adders.

Using full swing Vdd for carry-in reduces delay in multi-valued adders.

Binary full adders outperform multi-valued ones in carry-propagate adder configurations.

Abstract

In Carry Propagate Adders, carry propagation is the critical delay. The most efficient scheme is to generate Cout0 (Cin=0) and Cout1(Cin=1) and multiplex the correct output according to Cin. For any radix, the carry output is always 0/1. We present two versions of ternary adders with Cin = (0V, Vdd/2) and Cin = (0V, Vdd) and two versions of quaternary adders with Cin = (0V, Vdd/3) and Cin = (0V, Vdd). Using full swing Vdd for Cin reduces the propagation delays for ternary and quaternary adders. 6-bit, 4-trit and 3-quit CPAs are then compared.