SIMPLIS Parts

Exclusive OR/Exclusive NOR Gate

The Exclusive OR/Exclusive NOR Gate models both a generic exclusive OR and exclusive NOR gate. The number of active-low inputs can be set to either 0 or 1. Both exclusive-OR and exclusive-NOR outputs are provided. The outputs change state at the same time, making the outputs perfectly complementary.

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Model Name:

Exclusive OR/Exclusive NOR Gate

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_XOR_N: Without Ground Reference
  • SIMPLIS_DIGI1_XOR_Y: With Ground Reference

Symbol:

Multiple Selections:

Multiple exclusive-OR gates can be selected and edited at the same time.

Editing the Exclusive OR/Exclusive NOR Gate

To configure the exclusive OR/exclusive NOR gate, 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

# of Inverted Logic Inputs

Number of active-low logic inputs. Any device can have active-low inputs up to the # of Logic Inputs minus 1.

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 XOR 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 Exclusive OR/Exclusive NOR Gate 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 XOR / XNOR Gate 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

The following truth table is for a two-input Exclusive-OR gate with active-high inputs.

Inputs

Outputs

A

B

Exclusive-OR

 Exclusive-NOR

0

0

0

 1

0

1

1

 0

1

0

1

 0

1

1

0

 1

Examples

The test circuit used to generate the waveform examples in the next section can be downloaded here: simplis_058_exclusiveorgate_example.sxsch.

Waveforms

The waveforms below were taken from an exclusive-OR gate with both inputs selected to be active high. With this configuration, the exclusive-OR output will be high when one, but not both, of the A and B inputs are high.

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 exclusive-OR gate with active-high inputs and without ground reference would be as follows:
X$U1 5 8 2 3 SIMPLIS_DIGI1_XOR_N vars: NumInv=0 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

NumInv

# of Inverted Logic Inputs

  

0 to 1

  

Number of active-low logic inputs. Any device can have active-low inputs up to the # of Logic Inputs minus 1.

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 XOR / XNOR Gate 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 XOR 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 XOR / XNOR Gate 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