Static RC Delay Check (static_rcdelay)

Spectre Syntax

title static_rcdelay node=[n1 n2 ...] maxnrise=<value> minnrise=<value> maxnfall=<value> minnfall=<value> maxtrise=<value> mintrise=<value> maxtfall=<value> mintfall=<value> <inst=[inst1 inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> <depth=n> fanoutmargin=[lower_margin higher margin] cmin=<value> <detailed_path=[yes|no]>

SPICE Syntax

.cck title static_rcdelay node=[n1 n2 ...] maxnrise=<value> minnrise=<value> maxnfall=<value> minnfall=<value> maxtrise=<value> mintrise=<value> maxtfall=<value> mintfall=<value> <inst=[inst1 inst2...]> <xinst=[xinst1 xinst2...]> <subckt=[subckt1 subckt2....]> <xsubckt=[xsubckt1 xsubckt2....]> <depth=n> fanoutmargin=[lower_margin higher margin] cmin=<value> <detailed_path=[yes|no]>

Description

Reports nodes with excessive rise or fall times. Rise and fall times are based on estimation.

The static_rcdelay check analyzes only the fanout nodes. It does not check nodes that connect to MOSDIODEs or MOSCAPs. The check reports either the top worst case rise/fall times (maxnrise, maxnfall) or nodes with rise/fall times above the user-defined thresholds (maxtrise, maxtfall). In addition, the check reports the driving MOSFETs and the receiving MOSFET (gate connected to the analyzed node) for each node.

For postlayout netlist, the check supports only the backannotation (stitching) flow.

The results are reported into a file with the extension static.xml, which can be read with a Web browser.

Arguments

node	Nodes to which the check is applied. Default is none.
maxnrise	Report the top number nodes with highest rise time. Default is none.
minnrise	Report the top number nodes with lowest rise time. Default is none.
maxnfall	Report the top number nodes with highest fall time. Default is none.
minnfall	Report the top number nodes with lowest fall time. Default is none.
maxtrise	Report only those node names with rise time higher than the specified value. Default is infinity.
mintrise	Report only those node names with rise time lower than the specified value. Default is none.
maxtfall	Report only those node names with fall time higher than the specified value. Default is infinity.
mintfall	Report only those node names with fall time lower than the specified value. Default is none.
inst	Subcircuit instances to which the circuit check is applied. Default is inst=*
xinst	Subcircuit instances that are excluded from the circuit check. Default is none.
subckt	Instances of the specified subcircuit to which the circuit checks are applied. Default is subckt=*.
xsubckt	Instances of the specified subcircuit which are excluded from the circuit checks. Default is none.
depth	Hierarchy level (starting from top, instance, or subcircuit scope) to be checked. Default is 8.
fanoutmargin	Relative fanout level (in ratio of VDD voltage) for which rise and fall time is measured. The range of values is [0.01 0.99]. The default range is [0.1 0.9]. Lower margin should be less than the higher margin.
cmin	Node capacitance threshold. Only nodes with total capacitance higher than the specified value are reported. Default is 1e-14.
detailed_path	Report all possible (yes) or worst case (no) rise/fall time per node.Possible values are yes and no.

Example

Spectre Syntax

chk static_rcdelay node=[*] maxnrise=10 cmin=1e-14 detailed_path=no 

SPICE Syntax

.cck chk static_rcdelay node=[*] maxnrise=10 cmin=1e-14 detailed_path=no 

The above command will estimate the RC delay for all nodes. It will report four tables, one table for each parameter. It will report the maximum (highest) two rise delays.

The following is an example of the report that is displayed in the Web browser:

Related Topics

Static Checks

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