CMOS Buffer Gate

Symbol

Information

A CMOS Buffer Gate is used to isolate or amplify a signal while maintaining the same logical state at the output as the input. It acts as a voltage buffer with no change to the logical level, providing electrical isolation and signal amplification.

Ports

• Vin: Input voltage terminal

• Vout: Output voltage terminal

Model

The CMOS Buffer Gate model uses the same voltage at the output as the input.

Attributes:

• Vin (signal): Input voltage signal

• Vout (signal): Output voltage signal

• 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 behavior of the CMOS buffer gate.

Logic Table

Vin	Vout
LOW	LOW
HIGH	HIGH

Python

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

class CBuffer(model):
    """
    CMOS Buffer Gate model to isolate/amplify signals.
    """
    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 behavior of the CMOS buffer gate."""
        if self.Vin <= self.IL:
            self.Vout += self.OL  # Output LOW when input is LOW
        elif self.Vin >= self.IH:
            self.Vout += self.OH  # Output HIGH when input is HIGH
        else:
            # Handling intermediate voltage (uncertain state)
            self.Vout += (self.OL + self.OH) / 2  # Output is a mid-point voltage

Command Syntax

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

# Import the model
from pyams.models import CBuffer

# CBuffer instance creation
# Out, In: Connection points in the circuit
buffer_gate = CBuffer(Out, In)