set_noise_immunity_curve

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From: Jeffrey H Cui [mailto:jeffrey@marvell.com]
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2. Synopsys Commands Command Reference
set_noise_immunity_curve

Copyright 2009 Synopsys, Inc. All rights reserved.

NAME
set_noise_immunity_curve
Sets noise immunity curve for a library pin or port.

SYNTAX
int set_noise_immunity_curve
[-above]
[-below]
[-low]
[-high]
[-height height_value]
[-width width_value]
[-area area_value]
object_list

float height_value
float width_value
float area_value
list object_list

ARGUMENTS
-above Specifies an immunity curve for above ground or power rail noise
analysis region.

-below Specifies an immunity curve for below ground or power rail noise
analysis region.

-low Specifies an immunity curve for ground rail noise.

-high Specifies an immunity curve for power rail noise.

-height height_value
Specifies the height of the input voltage bump at the threshold
of logic failure. The height is in the voltage units of the
library.

-width width_value
Specifies the width of the input voltage bump at the threshold
of logic failure. The width is in the time units of the
library.

-area area_value
Specifies an area value for the curve. This parameter specifies
the size of the hyperbolic curve. 1.0.

object_list
Specifies a list of lib-pins or ports.

DESCRIPTION
Each cell input can tolerate a certain amount of noise without causing
a failure at the cell output. This characteristic is called noise immu-
nity. This command specifies noise immunity at library pins to deter-
mine whether noise failures occur as well as the amount of noise slack.

Noise immunity in the library can be specified as noise immunity
curves, polynomials, or tables or in terms of noise margins that con-
sider only the bump heights at the cell inputs.

This command specifies a noise immunity curve for a library pin or
design port. It can be used in the absence of library-specified noise
immunity characteristics, or to override the library-specified charac-
teristics by replacing them with a noise immunity curve. This command
will also override noise margins that have been annotated using the
set_noise_margin command,

The curve is hyperbolic with three coefficients to fully specify the
hyperbola: height and width of the input voltage bump at the threshold
of logic failure, and an area value to specify the size of the curve.
The three coefficients should be chosen to match the hyperbolic curve
to the data points obtained by laboratory characterization.

Noise immunity characteristics can vary for different noise bump types,
so there can be four different noise immunity curves associated with
each input: below low, above low, below high, and above high. All coef-
ficients are specified as positive numbers for all four types of noise
bumps.

report_noise_calculation will show whether noise immunity information
was taken from the library or annotated by this command.

EXAMPLES
This example specifies a noise height of 2, width of 3, area of 4 for
above the ground rail noise for pin A of library cell IV in the lsi_10k
library:

pt_shell> set_noise_immunity_curve -above -height 2 -width 3 \
-area 4 lsi_10k/IV/A

SEE ALSO
set_noise_margin (2), report_noise_calculation (2), remove_noise_immu-
nity_curve (2).

B-2008.12-SP2 Copyright (c) 2009 Synopsys, Inc. All rights reserved.