Verilog-A Language Reference Manual Analog Extensions to Verilog HDL Version 1.0 August 1, 1996 Open Verilog International No part of this work covered by the copyright hereon may be reproduced or used in any form or by any means -- - graphic, electronic, or mechanical, including photocopying, recording, taping, or information storage and retrieval systems --- without the prior written approval of Open Verilog International. Additional copies of this manual may be purchased by contacting Open Verilog International at the address shown below. Notices The information contained in this draft manual represents the definition of the Verilog-A hardware description language as proposed by OVI (Analog TSC) as of January, 1996. Open Verilog International makes no warran- ties whatsoever with respect to the completeness, accuracy, or applicability of the information in this draft man- ual to a user’s requirements. This language is not yet fully defined and is subject to change. It is suitable for learning how to do analog modeling and as a vehicle for providing feedback to the standards committee. Verilog- A should not be used for production design and development. Open Verilog International reserves the right to make changes to the Verilog-A hardware description language and this manual at any time without notice. Open Verilog International does not endorse any particular simulator or other CAE tool that is based on the Ver- ilog-A hardware description language. Suggestions for improvements to the Verilog hardware description language and/or to this manual are welcome. They should be sent to the address below. Information about Open Verilog International and membership enrollment can be obtained by inquiring at the address below. Published as: Verilog-A Language Reference Manual Version 1.0, August 1, 1996. Published by: Open Verilog International 15466 Los Gatos Blvd., #109071 Los Gatos, CA 95032 Phone: (408) 358-9510 Fax: (408) 358-3910 Printed in the United States of America. Verilog® is a registered trademark of Cadence Design Systems, Inc. The following people contributed to the creation, editing and review of this document. Ramana Aisola Motorola [email protected] Kevin Cameron Meta-Software [email protected] Dan FitzPatrick Apteq [email protected] Vassilios Gerousis Motorola [email protected] Ian Getreu Analogy [email protected] Kim Hailey Meta Software [email protected] Ken Kundert Cadence [email protected] Oskar Leuthold GEC Plessy [email protected] S. Peter Liebmann Meta Software [email protected] Ira Miller Motorola [email protected] Tom Reeder Viewlogic [email protected] Steffen Rochel Anacad/Mentor [email protected] James Spoto Cadence [email protected] Richard Trihy Cadence [email protected] Yatin Trivedi SEVA Technologies [email protected] Alex Zamfirescu Veribest a.zamfi[email protected] Table of Contents Verilog-A HDL Overview Overview ........................................................................................... 1-1 Systems ............................................................................................. 1-1 Conservative systems .................................................................. 1-2 Kirchhoff’s laws .......................................................................... 1-3 Signal-flow systems .................................................................... 1-4 Mixed systems ............................................................................ 1-5 Natures, disciplines and nodes .................................................... 1-7 Conventions used in this document .................................................. 1-8 Contents ............................................................................................ 1-9 Lexical Tokens Lexical tokens ................................................................................... 2-1 White space ....................................................................................... 2-1 Comments ......................................................................................... 2-1 Operators ........................................................................................... 2-2 Numbers ............................................................................................ 2-2 Integer constants ......................................................................... 2-2 Real constants ............................................................................. 2-3 Units for real constants ............................................................... 2-4 Conversion .................................................................................. 2-4 Identifiers, keywords, and system names ......................................... 2-5 Escaped identifiers ...................................................................... 2-5 Keywords .................................................................................... 2-5 Version 1.0 Verilog-A Language Reference Manual v System tasks and functions ......................................................... 2-7 Compiler directives ..................................................................... 2-7 Data Types Integer and real datatypes ................................................................. 3-1 Operators and real numbers ........................................................ 3-2 Conversion .................................................................................. 3-2 Parameters ......................................................................................... 3-2 Type Specification ...................................................................... 3-4 Value Range Specification .......................................................... 3-4 Nodes ................................................................................................ 3-5 Natures ........................................................................................ 3-5 Disciplines ................................................................................... 3-9 Node Declaration ...................................................................... 3-11 Implicit Nodes ........................................................................... 3-13 Node Compatibility ......................................................................... 3-13 Branches .......................................................................................... 3-15 Branch Declaration ................................................................... 3-15 Accessing Node and branch Signals and Attributes ................. 3-16 Namespace ...................................................................................... 3-17 Nature and Discipline ............................................................... 3-17 Node .......................................................................................... 3-17 Branch ....................................................................................... 3-18 Expressions Operators ........................................................................................... 4-1 Operators with real operands ...................................................... 4-2 Binary operator precedence ........................................................ 4-2 Expression evaluation order ........................................................ 4-3 Arithmetic operators ................................................................... 4-4 Relational operators .................................................................... 4-4 Equality operators ....................................................................... 4-5 Logical operators ........................................................................ 4-5 Version 1.0 Verilog-A Language Reference Manual vi Bit-wise operators ....................................................................... 4-6 Shift operators ............................................................................. 4-7 Conditional operator ................................................................... 4-7 Event or ....................................................................................... 4-7 Built-In Mathematical Functions ...................................................... 4-7 Standard Mathematical Functions ............................................... 4-8 Transcendental Functions ........................................................... 4-8 Environment Parameters ............................................................. 4-9 Error Handling ............................................................................ 4-9 Signal Access Functions ................................................................... 4-9 Analog Operators ............................................................................ 4-10 Restrictions on analog operators ............................................... 4-11 Analog Operators and Tolerances ............................................. 4-11 Time Derivative Operator ......................................................... 4-11 Time Integral Operator ............................................................. 4-12 Delay Operator .......................................................................... 4-13 Transition Filter ........................................................................ 4-13 Slew Filter ................................................................................. 4-16 Laplace Transform Filters ........................................................