NAME_TABLE:

C_Function_Name: cm_d_xnor

Spice_Model_Name: d_xnor

Description: "digital exclusive-nor gate"

PORT_TABLE:

Port Name: in out

Description: "input" "output"

Direction: in out

Default_Type: d d

Allowed_Types: [d] [d]

Vector: yes no

Vector_Bounds: [2 -] -

Null_Allowed: no no

PARAMETER_TABLE:

Parameter_Name: rise_delay fall_delay

Description: "rise delay" "fall delay"

Data_Type: real real

Default_Value: 1.0e-9 1.0e-9

Limits: [1.0e-12 -] [1.0e-12 -]

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: input_load

Description: "input load value (F)"

Data_Type: real

Default_Value: 1.0e-12

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

• Description:
  The digital xnor gate is an n-input, single-output xnor gate that produces an active `0' value if an odd number of its inputs are also `1' values. It produces a `1' output when an even number of `1' values occurs on its inputs. The delays associated with an output rise and those associated with an output fall may be specified independently. The model also posts an input load value (in farads) based on the parameter input load. The output of this model does not, however, respond to the total loading it sees on its output; it will always drive the output strongly with the specified delays. Note also that to maintain the technology-independence of the model, any UNKNOWN input, or any floating input causes the output to also go UNKNOWN.

Example SPICE Usage:

a9 [1 2] 8 xnor3

.model xnor3 d_xnor(rise_delay = 0.5e-9 fall_delay = 0.3e-9

+ input_load = 0.5e-12)