CMOS XNOR Gate

Symbol

Information

A CMOS XNOR Gate produces a HIGH (OH) output when both inputs are the same (either both LOW (IL) or both HIGH (IH)). Otherwise, the output is LOW (OL).

Ports

• In1: First input terminal

• In2: Second input terminal

• Out: Output terminal

Model

The CMOS XNOR Gate model implements standard XNOR logic behavior using voltage thresholds.

Attributes:

• In1 (signal): Input voltage at terminal In1

• In2 (signal): Input voltage at terminal In2

• Out (signal): Output voltage at terminal Out

• IL (param): Input LOW voltage threshold (default: 0.2V)

• IH (param): Input HIGH voltage threshold (default: 3.2V)

• OL (param): Output LOW voltage (default: 0.0V)

• OH (param): Output HIGH voltage (default: 5.0V)

Methods:

• analog(): Defines the XNOR gate behavior based on voltage thresholds.

Logic Table

In1	In2	Out
LOW	LOW	HIGH
LOW	HIGH	LOW
HIGH	LOW	LOW
HIGH	HIGH	HIGH

Python

from pyams.lib import model, signal, param, voltage

class CXNOR(model):
    """
    CMOS XNOR Gate model using voltage threshold logic.
    """
    def __init__(self, Out, In1, In2):
        # Signal declarations
        self.In1 = signal('in', voltage, In1)
        self.In2 = signal('in', voltage, In2)
        self.Out = signal('out', voltage, Out)

        # Parameter declarations
        self.IL = param(0.2, 'V', 'Input LOW voltage threshold')
        self.IH = param(3.2, 'V', 'Input HIGH voltage threshold')
        self.OL = param(0.0, 'V', 'Output LOW voltage')
        self.OH = param(5.0, 'V', 'Output HIGH voltage')

    def analog(self):
        """Defines the XNOR gate behavior using voltage threshold logic."""
        if (self.In1 <= self.IL and self.In2 <= self.IL) or (self.In1 >= self.IH and self.In2 >= self.IH):
            self.Out += self.OH  # Output HIGH when both inputs are the same
        else:
            self.Out += self.OL  # Output LOW when inputs are different

Command Syntax

The syntax for defining a CMOS XNOR gate in a PyAMS simulation:

# Import the model
from pyams.models import CXNOR

# CXNOR instance creation
# Out, In1, In2: Connection points in the circuit
xnor_gate = CXNOR(Out, In1, In2)