CMOS OR Gate

Symbol

Information

A CMOS OR Gate is a fundamental digital logic gate that implements logical disjunction. The output is HIGH (OH) if at least one input is HIGH (IH); otherwise, the output is LOW (OL).

The gate operates based on voltage thresholds:

• If both inputs are LOW (u2264 IL), the output is LOW (OL).

• If at least one input is HIGH (u2265 IH), the output is HIGH (OH).

• Intermediate voltages are not handled explicitly in this model.

Ports

• In1: First input terminal

• In2: Second input terminal

• Out: Output terminal

Model

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

Attributes:

• In1 (signal): Input voltage at In1

• In2 (signal): Input voltage at In2

• Out (signal): Output voltage at 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 OR gate behavior based on voltage thresholds.

Logic Table

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

Python

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

class COR(model):
    """
    CMOS OR Gate model using voltage threshold logic.
    """
    def __init__(self, O, I1, I2):
        # Signal declarations
        self.In1 = signal('in', voltage, I1, '0')
        self.In2 = signal('in', voltage, I2, '0')
        self.Out = signal('out', voltage, O, '0')

        # 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 OR gate behavior using voltage threshold logic."""
        if (self.In1 <= self.IL) and (self.In2 <= self.IL):
            self.Out += self.OL  # Output LOW if both inputs are LOW
        elif (self.In1 >= self.IH) or (self.In2 >= self.IH):
            self.Out += self.OH  # Output HIGH if at least one input is HIGH

Command Syntax

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

# Import the model
from pyams.models import COR

# COR instance creation
# O, I1, I2: Connection points in the circuit
or_gate = COR(O, I1, I2)