Proposed circuit for fast XOR-XNOR operations Presented by: Ila Sharma(102001) Harsh Magotra (102012)
INTRODUCTION TO OUR IDEA Considering the earlier designs for XOR-XNOR CIRCUIT, we are introducing an idea to make the circuit more fast, noise immune, low voltage consuming…… so we have come with a circuit having less no. of CMOS and posses all the above said features.
What is XOR GATE? INPUT OUTPUT A B A XOR B 0 0 0 0 1 1 1 0 1 1 1 0
WHAT IS XNOR GATE? A B A xnor B 0 0 1 0 1 0 1 0 0 1 1 1
XOR GATE USING CMOS X X O O R R C Ci irrc c u ui itt VDD b a a b a b a a b b
XNOR using X X N N O O R R C Ci irrc c u ui itt CMOS VDD a b b a a b a a b b
PRIMITIVE XOR-XNOR CIRCUIT This circuit mostly find use in design of multipliers, comparators, converters..etc. Have 10 transistors Consume more power More time delay Skewed output
PROPOSED XOR- XNOR CIRCUIT -Have 8 transistors -Consume LESS power -LESS time delay -REMOVES Skewed output problem -More noise tolerant
INDIVIDUAL UNITS OF PROPOSED XOR-XNOR CIRCUIT
COMPARISON BETWEEN THE TWO Earlier circuit Proposed circuit X X O O R R C Ci irrc c u ui itt VDD b a a b a b a a b b
Earlier circuit Proposed circuit X X N N O O R R C Ci irrc c u ui itt VDD a b b a a b a a b b
DESIGN METRICS How to evaluate the performance of the circuit??? Cost Speed Power dissipation Delays Noise tolerance
NOISE TOLERANCE we use the noise immunity curves, NIC to measure the noise-tolerance of XOR- XNOR circuits. The noise immunity curve ,NIC of a digital gate is a locus of points (Tn, Vn) for which the gate just makes a logic error. The higher the NIC of a gate, the less susceptible is the gate to noise.
CONCLUSION A new XOR-XNOR circuit implementation has been proposed and it seems that our proposal may be particularly suited for low voltage requirements. From our point of view the most important output of the described proposal is emerging hope that proposed circuit would find use in fast arithmetic operations and will be more noise immune.