CMOS NOT Gate (Inverter)

Symbol

Information

A CMOS NOT Gate (also known as an inverter) outputs the inverse of the input signal. If the input is HIGH (IH), the output is LOW (OL), and vice versa.

The gate operates based on voltage thresholds:

• If the input is LOW (≤ IL), the output is HIGH (OH).

• If the input is HIGH (≥ IH), the output is LOW (OL).

• Intermediate voltages are not handled explicitly in this model.

Ports

• In: Input terminal

• Out: Output terminal

Model

The CMOS NOT Gate model implements standard NOT logic behavior using voltage thresholds.

Attributes:

• Vin (signal): Input voltage at In

• Vout (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 NOT gate behavior based on voltage thresholds.

Logic Table

Vin	Vout
LOW	HIGH
HIGH	LOW

Python

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

class CNOT(model):
    """
    CMOS NOT Gate (Inverter) model using voltage threshold logic.
    """
    def __init__(self, Out, In):
        # Signal declarations
        self.Vin = signal('in', voltage, In)
        self.Vout = 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 NOT gate behavior using voltage threshold logic."""
        if self.Vin <= self.IL:
            self.Vout += self.OH  # Output HIGH when input is LOW
        elif self.Vin >= self.IH:
            self.Vout += self.OL  # Output LOW when input is HIGH

Command Syntax

The syntax for defining a CMOS NOT gate in a PyAMS simulation:

# Import the model
from pyams.models import CNOT

# CNOT instance creation
# Out, In: Connection points in the circuit
not_gate = CNOT(Out, In)