Liberty User Guides and Reference Manual Suite Version 2017

1 Liberty user Guides and Reference Manual SuiteVersion 1 The Liberty user Guides and Reference Manual Suite includes the following documents: Liberty Release Notes Liberty user Guide Volume 1 Liberty user Guide Volume 2 Liberty Reference ManualNote: The contents of Liberty user Guide Volume 2 have not changed since the can use Adobe Reader Version 7 or later to view the Liberty user Guides and Reference Manual navigate through the Liberty user Guides and Reference Manual Suite , you can use the View > Go To menu item and select the appropriate option. 2017 Synopsys, Inc. All rights Release NotesVersion release notes present the latest information about Liberty Version New modeling syntax and enhancements are described in the following sections: New LVF Models Partial Voltage Swing in Timing ArcsFor detailed information about these enhancements, see the Liberty user Guide, Vol.

2 LVF Models 2 Liberty Release NotesVersion LVF ModelsThe following new LVF models are introduced: OCV Models for Retain Arc Delay and Transition Statistical Moments-Based LVF Models For Ultra-Low Voltage DesignsOCV Models for Retain Arc Delay and TransitionA retain arc models how long an output port retains its current logic value after a voltage rise or fall at a related input port. The Liberty syntax now supports new Liberty Variation Format (LVF) models in timing groups for on-chip variation (OCV) in delay and transition times of retain model the retain arc OCV delay, use the new ocv_sigma_retaining_rise and ocv_sigma_retaining_fall groups. Each of these groups specify a lookup table for the delay variation at the standard deviation ( ) value from the nominal retain arc rise and fall delays, respectively. Use the sigma_type attribute to define the type of arrival time in the lookup model the retain arc OCV transition, use the new ocv_sigma_retain_rise_slew and ocv_sigma_retain_fall_slew groups.

3 Each of these groups specify a lookup table for the transition variation at the standard deviation ( ) value from the nominal retain arc rise and fall transitions, Moments-Based LVF Models For Ultra-Low Voltage DesignsThe LVF models for OCV now support asymmetric, biased, or non-Gaussian distributions of timing variation. This is useful to accurately model ultra-low voltage libraries. To capture the shape of a biased timing variation distribution, the LVF models use the statistical moments including the mean, standard deviation, and skewness of the syntax includes Liberty groups with lookup tables to store the moments-based variation values of the cell delays, cell transitions, cell timing constraints, retain arc delays, and retain arc transitions at one-sigma ( ) deviation. These lookup tables can be scalar, one, two, or three-dimensional and are defined under the timing group together with the nominal timing tables.

4 The lookup table template for these groups are defined at the library-level using the lu_table_template Voltage Swing in Timing Arcs 3 Liberty Release NotesVersion OCV Mean Shift GroupsThe new ocv_mean_shift_cell_rise, ocv_mean_shift_cell_fall, ocv_mean_shift_rise_transition, ocv_mean_shift_fall_transition, ocv_mean_shift_retaining_rise, ocv_mean_shift_retaining_fall, ocv_mean_shift_retain_rise_slew, ocv_mean_shift_retain_fall_slew, ocv_mean_shift_rise_constraint, and ocv_mean_shift_fall_constraint lookup tables specify the offset value from the mean of the timing variation distribution to the nominal OCV Standard Deviation GroupsThe new ocv_std_dev_cell_rise, ocv_std_dev_cell_fall, ocv_std_dev_rise_transition, ocv_std_dev_fall_transition, ocv_std_dev_retaining_rise, ocv_std_dev_retaining_fall, ocv_std_dev_retain_rise_slew, ocv_std_dev_retain_fall_slew, ocv_std_dev_rise_constraint, and ocv_std_dev_fall_constraint look up tables store the values of standard deviation of the timing variation OCV Skewness GroupsThe new ocv_skewness_cell_rise, ocv_skewness_cell_fall, ocv_skewness_rise_transition, ocv_skewness_fall_transition, ocv_skewness_retaining_rise, ocv_skewness_retaining_fall, ocv_skewness_retain_rise_slew, ocv_skewness_retain_fall_slew, ocv_skewness_rise_constraint, ocv_skewness_fall_constraint lookup tables specify the skewness values of the timing variation Voltage Swing in Timing ArcsYou can now specify the partial voltage swing for a specific timing arc.

5 To do so, define the output_signal_level_low and output_signal_level_high attributes in the timing group. These attributes specify the actual output voltages of an output pin after a transition through a timing specify these attributes in the timing group when the following occur together: The cell output exhibits partial voltage swing (and not rail-to-rail swing). The voltages are different in different timing user GuideVolume 1 Version , June 2017 Liberty user Guide, Volume 1, Version Notice 2004, 2006-2009, 2011-2017 Synopsys, Inc. All rights reserved. This software and documentation contain confidential and proprietary information that is the property of Synopsys, Inc. The software and documentation are furnished under a license agreement and may be used or copied only in accordance with the terms of the license agreement. No part of the software and documentation may be reproduced, transmitted, or translated, in any form or by any means, electronic, mechanical, Manual , optical, or otherwise, without prior written permission of Synopsys, Inc.

6 , or as expressly provided by the license to Copy DocumentationThe license agreement with Synopsys permits licensee to make copies of the documentation for its internal use only. Each copy shall include all copyrights, trademarks, service marks, and proprietary rights notices, if any. Licensee must assign sequential numbers to all copies. These copies shall contain the following legend on the cover page:This document is duplicated with the permission of Synopsys, Inc., for the use of Open Source Liberty Control StatementAll technical data contained in this publication is subject to the export control laws of the United States of America. Disclosure to nationals of other countries contrary to United States law is prohibited. It is the reader's responsibility to determine the applicable regulations and to comply with , INC., AND ITS LICENSORS MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR and certain Synopsys product names are trademarks of Synopsys, as set forth other product or company names may be trademarks of their respective LinksAny links to third-party websites included in this document are for your convenience only.

7 Synopsys does not endorse and is not responsible for such websites and their practices, including privacy practices, availability, and , E. Middlefield RoadMountain View, CA Sample Library DescriptionGeneral Syntax.. 1-2 Statements .. 1-3 Group Statements .. 1-3 Attribute Statements .. 1-4 Simple Attributes.. 1-4 Complex Attributes .. 1-4 Define Statements .. 1-5 Reducing Library File Size.. 1-52. Building a Technology LibraryCreating Library Groups .. 2-2library Group .. 2-2 Using General Library Attributes.. 2-2technology Attribute.. 2-2delay_model Attribute .. 2-3bus_naming_style Attribute .. 2-3 Delay and Slew Attributes.. 2-3input_threshold_pct_fall Simple Attribute .. 2-5input_threshold_pct_rise Simple Attribute .. 2-6output_threshold_pct_fall Simple Attribute .. 2-6output_threshold_pct_rise Simple Attribute.. 2-7slew_derate_from_library Simple Attribute.

8 2-7slew_lower_threshold_pct_fall Simple Attribute .. 2-7 ContentsivLiberty user Guide, Volume user Guide, Volume 1 Version Simple Attribute .. 2-8slew_upper_threshold_pct_fall Simple Attribute .. 2-8slew_upper_threshold_pct_rise Simple Attribute.. 2-8 Defining Units .. 2-9time_unit Attribute .. 2-9voltage_unit Attribute .. 2-10current_unit Attribute .. 2-10pulling_resistance_unit Attribute .. 2-10capacitive_load_unit Attribute .. 2-11leakage_power_unit Attribute .. 2-113. Building EnvironmentsLibrary-Level Default Attributes .. 3-2 Setting Default Cell Attributes .. 3-2default_cell_leakage_power Simple Attribute.. 3-2 Setting Default Pin Attributes.. 3-2 Setting Wire Load Defaults .. 3-3default_wire_load Attribute.. 3-3default_wire_load_capacitance Attribute .. 3-3default_wire_load_resistance Attribute.. 3-3default_wire_load_area Attribute.

9 3-4 Setting Other Environment Defaults .. 3-4default_operating_conditions Attribute .. 3-4default_connection_class Attribute.. 3-4 Examples of Library-Level Default Attributes.. 3-5 Defining Operating Conditions .. 3-5operating_conditions Group .. 3-5 Defining Power Supply Cells .. 3-7power_supply group .. 3-7 Defining Wire Load Groups.. 3-7wire_load Group .. 3-8wire_load_table Group.. 3-9 Specifying Delay Scaling Attributes .. 3-10 Pin and Wire Capacitance Factors .. 3-10 Scaling Factors Associated With the Nonlinear Delay Model .. 3-10 Chapter 1: Contents1-vContentsvLiberty user Guide, Volume 1 Version Defining Core CellsDefining cell Groups .. 4-2cell Group .. 4-2area Attribute .. 4-3cell_footprint Attribute .. 4-3clock_gating_integrated_cell Attribute .. 4-4 Setting Pin Attributes for an Integrated Cell .. 4-5 Setting Timing for an Integrated Cell.

10 4-6contention_condition Attribute .. 4-6is_macro_cell Attribute .. 4-6pad_cell Attribute.. 4-7pin_equal Attribute.. 4-7pin_opposite Attribute .. 4-7type Group.. 4-7cell Group Example .. 4-8mode_definition Group .. 4-9 Group Statement.. 4-10mode_value Group .. 4-10 Defining pin Groups .. 4-11pin Group.. 4-11 General pin Group Attributes.. 4-12capacitance Attribute .. 4-13clock_gate_clock_pin Attribute .. 4-13clock_gate_enable_pin Attribute.. 4-14clock_gate_obs_pin Attribute .. 4-14clock_gate_out_pin Attribute .. 4-14clock_gate_test_pin Attribute .. 4-14complementary_pin Simple Attribute .. 4-15connection_class Simple Attribute .. 4-15direction Attribute .. 4-17driver_type Attribute .. 4-17fall_capacitance Attribute .. 4-21fault_model Simple Attribute .. 4-22inverted_output Attribute.