NAME_TABLE:

C_Function_Name: cm_oneshot

Spice_Model_Name: oneshot

Description: "controlled one-shot"

PORT_TABLE:

Port Name: clk cntl_in

Description: "clock input" "control input"

Direction: in in

Default_Type: v v

Allowed_Types: [v,vd,i,id] [v,vd,i,id]

Vector: no no

Vector_Bounds: - -

Null_Allowed: no yes

PORT_TABLE:

Port Name: clear out

Description: "clear signal" "output"

Direction: in out

Default_Type: v v

Allowed_Types: [v,vd,i,id] [v,vd,i,id]

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes no

PARAMETER_TABLE:

Parameter_Name: clk_trig retrig

Description: "clock trigger value" "retrigger switch"

Data_Type: real boolean

Default_Value: 0.5 FALSE

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: no yes

PARAMETER_TABLE:

Parameter_Name: pos_edge_trig

Description: "positive/negative edge trigger switch"

Data_Type: boolean

Default_Value: TRUE

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: no

PARAMETER_TABLE:

Parameter_Name: cntl_array pw_array

Description: "control array" "pulse width array"

Data_Type: real real

Default_Value: 0.0 1.0e-6

Limits: - [0.00 -]

Vector: yes yes

Vector_Bounds: - cntl_array

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: out_low out_high

Description: "output low value" "output high value"

Data_Type: real real

Default_Value: 0.0 1.0

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: fall_time rise_time

Description: "output fall time" "output rise time"

Data_Type: real real

Default_Value: 1.0e-9 1.0e-9

Limits: - -

Vector: no no

Vector_Bounds: - -

Null_Allowed: yes yes

PARAMETER_TABLE:

Parameter_Name: rise_delay

Description: "output delay from trigger"

Data_Type: real

Default_Value: 1.0e-9

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

PARAMETER_TABLE:

Parameter_Name: fall_delay

Description: "output delay from pw"

Data_Type: real

Default_Value: 1.0e-9

Limits: -

Vector: no

Vector_Bounds: -

Null_Allowed: yes

• Description:
  This function is a controlled oneshot with parametrizable values of low and high peak output, input trigger value level, delay, and output rise and fall times. It takes an input voltage or current value. This value is used as the independent variable in the piecewise linear curve described by the coordinate points of the cntl_array and pw_array pairs. From the curve, a pulse width value is determined. The one-shot will output a pulse of that width, triggered by the clock signal (rising or falling edge), delayed by the delay value, and with specified rise and fall times. A positive slope on the clear input will immediately terminate the pulse, which resets with its fall time.
  From the above, it is easy to see that array sizes of 2 for both the cntl_array and the pw_array will yield a linear variation of the pulse width with respect to the control input. Any sizes greater than 2 will yield a piecewise linear transfer characteristic. For more detail, refer to the description of the piecewise linear controlled source, which uses a similar method to derive an output value given a control input.

Example SPICE Usage:

ain 1 2 3 4 pulse2

.model pulse2 oneshot(cntl_array = [-1 0 10 11]

+ pw_array=[1e-6 1e-6 1e-4 1e-4]

+ clk_trig = 0.9 pos_edge_trig = FALSE

+ out_low = 0.0 out_high = 4.5

+ rise_delay = 20.0-9 fall_delay = 35.0e-9)