ECAD SCHEMATIC CAPTURE

Fred Heep/George Austin SFU Engineering Science June 2000 What is ECAD?

■ Electronic Aided Design

■ Typical uses may include ◆ Schematic Capture ◆ PWB Design ◆ Simulation/Analysis ◆ Product Production Documentation EDA TOOLS

■ Electronic Design Automation

■ Complete design ◆ Schematic entry ◆ Mixed-signal simulation ◆ PLD design ◆ PWB layout with Autorouting ◆ Signal intregrity simulation ◆ 3D PWB viewing ◆ Integrated document management ECAD Benefits

♦ Neat, professional drawings

♦ Easy coordination of multiple sheet drawings (hierarchical)

♦ Changes to all aspects of a project can be easily updated (with quality up-to-date software)

♦ Easy to get data, production docs/files out

♦ Forward & back annotation keep schematics and PWB designs in sync; helps to avoid errors. ECAD Benefits - cont’d

♦ Electrical & mechanical design rule parameters (PWB placement & routing) are quickly checked

♦ More easily linked to ATE & production machine processes

♦ With some classier products, engineers can add notes and formulas to nets. Very useful for PWB designers and production floor assembly/calibration/testing. ECAD Shortcomings

♦ Expensive ($300 - 60K USD)

♦ Challenging to get data in

♦ Can be significantly slower than hand drawing until proficient (software package dependent)

♦ Simple tasks can be very frustrating & gross time-wasters to accomplish until expertise is developed with the software

♦ Often steep learning curve ECAD Shortcomings - cont’d

♦ give false sense of security that calculations, placement, routing, etc. are done correctly

♦ Can be challenging to share info with others who do not have the same software package.

♦ Takes discipline to maintain accurate software file management for revision levels and backups

♦ Software formats change rapidly and long term compatibility with even the same brand of software is generally not possible. ECAD Shortcomings - cont’d

♦ Compatibility between software packages is virtually non-existent and there are no industry standards.

♦ Symbol libraries are getting to be huge and very cumbersome to manage.

♦ Each software package is good at some things, lousy at others. There’s no end-all/be-all.

♦ Loss of work due to power crashes, viruses, etc.

♦ Some software packages require security dongles. Some Popular ECAD Software Companies ♦ OrCad ♦ ACCEL Technologies – Tango, p-cad ♦ CadStar ♦ Cadence ♦ Mentor Graphics ♦ Protel ♦ CADSoft USA – EAGLE ♦ IVEX ♦ PADS ♦ Workbench ♦ CircuitMaker What is PSPICE?

■ SPICE =Simulation Program with Emphasis

■ Developed at University of California at Berkeley

■ PSPICE is a derivation of SPICE written by MicroSim (now owned by Orcad) Why we’ve chosen to use PSPICE V8

♦ Free functional evaluation version ♦ Generally quite easy to use (but limited in complexity & functionality) ♦ Can do simulation of some circuits

■ Full professional copy is installed on Lab network (CAD1, PIT1, PIT2, PIT3, PIT9, PIT8)

■ MicroSim Release 8.0 evaluation version is installed on all other PIT & CAD NT Workstations. PSPICE Components

◆ Schematic Capture ◆ PWB Design ◆ Simulation Things to Explore in PSPICE V8 ◆ Setting up a new drawing ◆ Setting grids and other options ◆ Setting up title blocks ◆ Placing, moving & rotating entities ◆ Zooming and panning ◆ Altering component attributes ◆ Connecting parts ◆ Adding text Typical E-Schematic Design Steps ◆ Select Page Size and Title block ◆ Setting up the title block ◆ Place major component symbols ◆ Interconnect component symbols ◆ Assign component values ◆ Create custom components ◆ Perform Electrical Rule Check (ERC) ◆ Create a netlist ◆ Create Bill of Materials (BOM) ◆ Adjust placement for readability Creating Custom Libraries

◆ Create component PWB footprint ◆ Create schematic graphics symbol ◆ Set/alter device attributes ◆ Setup ERC functions for each pin ◆ Save the new part in a library PSPICE Simulation Example

■ Equal Component Salen Key LPF

■ Special Considerations ◆ Use only supplied PSPICE library parts ◆ Must use power supply (batteries) ◆ Must use special PSPICE ground ◆ Must specify PSPICE signal source ◆ Must define output signals

■ Must create netlist

■ Run simulation Good Luck!

■ Fred & George