SIMPLIS Parts

Inverter/Buffer

The Inverter/Buffer models a generic inverter and buffer. Perfectly complementary outputs are provided with both outputs changing state after the Propagation Delay.

In this Topic Hide

Model Name:

Inverter/Buffer

Simulator:

This device is compatible with the SIMPLIS simulator.

Parts Selector
Menu Location:

Digital Functions | Gates

Symbol Library:

None - the symbol is automatically generated when placed or edited.

Model File:

SIMPLIS_DIGI1.lb

Subcircuit Name:

  • SIMPLIS_DIGI1_BUF_N: Without Ground Reference
  • SIMPLIS_DIGI1_BUF_Y: With Ground Reference

Symbol:

Multiple Selections:

Multiple inverters/buffers can be selected and edited at the same time.

Editing the Inverter/Buffer

To configure the inverter/buffer, follow these steps:

  1. Double click the symbol on the schematic to open the editing dialog to the Parameters tab.
  2. Make the appropriate changes to the fields described in the table below the image.
Label Parameter Description

Delay

Delay from when any input pin changes state until the outputs change state

Ground Ref

Determines whether or not a device has a ground reference pin.

Any digital component that has an input or output pin connected to an analog circuit node must have its Ground Ref pin connected to an analog node. This is usually the ground on the schematic. Click on the Help button for more information.

Initial Condition

Initial condition of the non-inverted output at t=0

To define the parameters for the interface between this digital component and each analog component connected directly to an input or output pin, follow these steps from the Edit Inverter/Buffer dialog box:

  1. Click on the   Interface   tab.
  2. Make the appropriate changes to the fields described in the table below the image.
Label Parameter Description

Input Resistance

Input resistance of each input pin

Threshold

Hysteresis

The Threshold (T) and Hysteresis (H) of the Schmitt trigger input buffer on each Inverter / Buffer input. To determine the low-to-high threshold (TH) and the high-to-low threshold (TL), substitute Threshold (T) and Hysteresis (H) in each of the following formulas :
Input Logic Transition Actual Threshold
0 ➞ 1 TH = Threshold + 0.5 * Hysteresis
1 ➞ 0 TL = Threshold - 0.5 * Hysteresis
 

Output Resistance

Output resistance of each output pin

Output High Voltage

Output high voltage for each output pin

Output Low Voltage

Output low voltage for each output pin

Truth Table

Input

Outputs

Buffer

 Inverter

0

0

 1

1

1

 0

Examples

The test circuit used to generate the waveform examples in the next section can be downloaded here: simplis_059_inverter_example.sxsch.

Waveforms

The waveforms below were taken from a simple inverter test circuit where the input is connected to a digital pulse source.

Subcircuit Parameters

The subcircuit parameters, parameter names, data types, ranges, units, and descriptions are in the following table. The parameter names can be used to directly generate netlist entries for the device. For example, the netlist entry for an inverter/buffer with active-high inputs and without ground reference would be as follows:
X$U1 3 4 2 SIMPLIS_DIGI1_BUF_N vars: IC=0 RIN=10Meg ROUT=10 HYSTWD=1 VOL=0 VOH=5 DELAY=2p TH=2.5


Parameter Name Label Data Type Range Units Parameter Description

DELAY

Delay

  

1f to 1024

s

Delay from when any input pin changes state until the outputs change state

HYSTWD

Hysteresis

    

V

The Threshold (T) and Hysteresis (H) of the Schmitt trigger input buffer on each Inverter / Buffer input. To determine the low-to-high threshold (TH) and the high-to-low threshold (TL), substitute Threshold (T) and Hysteresis (H) in each of the following formulas :

Input Logic Transition Actual Threshold
0 ➞ 1 TH = Threshold + 0.5 * Hysteresis
1 ➞ 0 TL = Threshold - 0.5 * Hysteresis
 

IC

Initial Condition

LIST

0,
1

  

Initial condition of the non-inverted output at t=0

RIN

Input Resistance

  

min: 100

Ω

Input resistance of each input pin

VOH

Output High Voltage

    

V

Output high voltage for each output pin

VOL

Output Low Voltage

    

V

Output low voltage for each output pin

ROUT

Output Resistance

  

min: 1m

Ω

Output resistance of each output pin

TH

Threshold

    

V

The Threshold (T) and Hysteresis (H) of the Schmitt trigger input buffer on each Inverter / Buffer input. To determine the low-to-high threshold (TH) and the high-to-low threshold (TL), substitute Threshold (T) and Hysteresis (H) in each of the following formulas :

Input Logic Transition Actual Threshold
0 ➞ 1 TH = Threshold + 0.5 * Hysteresis
1 ➞ 0 TL = Threshold - 0.5 * Hysteresis