Altera SDC and TimeQuest API - Manual (Page 73)

Chapter 2: SDC and TimeQuest API Package and Commands 2–63
sdc_ext
© December 2009 Altera Corporation SDC and TimeQuest API Reference Manual
set_timing_derate
Usage
set_timing_derate [-cell_delay] [-early] [-late] [-net_delay] [-operating_conditions
<operating_conditions>] <derate_value> <cells>
Options
-cell_delay: Specifies that derating factors are only to apply to cell delays
-early: Specifies the minimum derating factor. This factor specifies how early the
signal can arrive
-late: Specifies the maximum derating factor. This factor specifies how late the signal
can arrive
-net_delay: Specifies that derating factors are only to apply to net delays
-operating_conditions <operating_conditions>: Operating conditions Tcl object
<derate_value>: Timing derate value
<cells>: List of cell type objects
Description
Sets the global derate factors for the current design. The maxmimum and minimum delays of all timing
arcs in the design are multiplied by the factors specified with the -late and -early options respectively. Only
positive derate factors are allowed. If neither the -cell_delay nor -net_delay option is used, the derating
factors apply to both cell and net delays.
Specifying a derate value of less than 1.0 for the -late option or a derate value of greater than 1.0 for the
-early option reduces delay pessimisim, which might lead to optimistic results from timing analysis.
The effect of set_timing_derate command is deferred until the next time update_timing_netlist is called. To
reset derate factors to original values, use the reset_timing_derate command.
Example
set_timing_derate -early 0.9 [get_cells *]
set_timing_derate -late 1.1 [get_cells *]