1. Outcome 1
Investigate ECAD Systems

2. Expectation after studying this outcome?
 Student able to source the market for ECAD
tools based on their work requirement.
 Student able to identify whether the features of a
particular ECAD system fulfill their needs.
 Student able to make critical comparison among
the ECAD tools in the market.

3. What is an ECAD?
 ECAD - Electronic Computer-Aided Design.
 The use of computer technology to aid in the
drafting/design of a product.

4. Type of ECAD tools according to
industries
 Board-level design
 PCB layout design tools
 SPICE simulation
 Analogue and Digital schematic design tools
 IC-level design
 ASIC layout design tools
 SPICE simulation
 PLD schematic for HDL simulation

5. Categories of ECAD tools (pg 1-2)
 According to stages of the design process:
 Design entry stage
 Functional verification stage
 Physical design stage
 Physical verification and testing stage

6. Design entry stage
 Designer use pre-defined schematic symbols to
design desire circuit.
 The circuit is then translate into SPICE script for
simulation.
 Without this tools, designers wishing to simulate
their circuits will have to write the SPICE scripts
themselves.

7. Functional verification stage
 Tools used at this stage are simulation and
analysis tools.
 Think of them as your virtual lab instrument.
 Designer will know from simulation results
whether a design idea is workable or not.
 Three major types of analysis (Appendix C):
 AC analysis
 Analyze circuit gain and phase across a range of frequency.
 DC analysis
 Analyze DC voltage level at various circuit nodes.
 Transient analysis
 Time domain analysis simulates circuit response over time.

8. Physical design stage
 Conversion from schematic design into layout
design.
 The layout maybe PCB layout or IC-mask layout.
 Nowadays, these tools will do an automatic
conversion.

9. Physical verification and testing stage
 Physical verification tools ensures that the
physical layouts conform to design rules so that
the intended functionality is not jeopardized by
layout-induces parasitic, cross-talk and other
effects.
 The verification tools include:
 DRC
 Design Rule Check
 ERC
 Electric design Rule Check
 LVS
 Mask Layer Versus Schematic check

10. Importance of ECAD tools (pg 1-4)
 Without computer simulation, the workability of a design
could only be tested out after board assembly process.
Here to known
whether the circuit
workable or not!
Waste of time and
resources $$$$$.

11. Importance of ECAD tools
 Without the ability to do testing and verification at each
stage, you will find it very difficult to single-out defects
after assembly process.
 Because there are more variables to rule out.
 Is the design itself flawed?
 Is the PCB layout erroneous?
 Is some parts or components wrongly assembled?
 You would have a tough time to rule out the real root
cause of the problem.
 And, in manufacturing industry, time and $$$$$ is the
real problem so, this can’t be allowed to happens.

12. Design process improved with ECAD
tools
 Having implement ECAD system in the process, any
design flawed can be detect through simulation.
ECAD system here
Another
ECAD
system
here

13. Design process improved with ECAD
tools
 With ECAD virtual simulation capability, any
design flaw can be detect and re-design without
involving actual assembly and testing on real
physical parts.
 This would certainly prevent wastage of time and
resources at the PCB layout and assembly
stages.

14. Common features of ECAD systems
 Below list some common features that a
designer would find desirable as the basic
package of the ECAD systems they seek to
purchase and use (pg 1-7 to 1-19):
 Schematic capture
 SPICE model simulation
 HDL model simulation
 Components database / library
 Hierarchical design
 Mask layout editor
 Cross-section viewer
 Verification tools
 Waveform viewer
 PCB layout editor

15. Schematic capture (pg 1-7)
 Schematic capture allows user to choose from a
list of pre-generated SPICE-model schematic
component and drop them onto the design
workspace.
Drag and drop features
SPICE-model
SPICE-model

16. SPICE-model simulation (pg 1-9)
 SPICE-model simulation using DC analysis, AC
analysis and transient analysis. And some virtual
instrument such as multimeter, oscilloscope,
logic analyzer…etc.

17. HDL-model simulation (pg 1-12)
 Take a symbol, and describe its function using
Hardware Descriptive Language.
 Thus, allowing the symbol to be used directly in
ECAD systems that recognize HDL language.
HDL Symbol

18. Component database/library (pg 1-13)
 It would help the
designer a great deal
if the components
database/library covers
extensively those real
components available
on the market.

19. Hierarchical design (pg 1-14)
Basic cell
Flip-flop
Shift
register

20. Mask layout editor (pg 1-16)
 Allows designer to
graphically design the
layout masks,
automatically tracking
the layers, and
providing basic
primitives for the
designer to build
circuits with.
Cross-Section ViewerMask layout of entire chip

21. Cross-section viewer (pg 1-17)
 A feature often comes with
mask layout editing tools to
help user verify on-the-go the
cross sections of doped
regions.
 Very helpful tool for designer
as the doping geometries
never ideal and important to
make sure masks designed
will not result in under-doped
regions or over-doped
regions.
Inverter Cross-section

22. Verification tools (DRC, ERC, LVS) (pg 1-17)
 Most ECAD software often includes verification
algorithms that help the designer verify the
layout design.
 Design Rule Check is a feature available in most
IC layout design editor.
 Electrical Rule Check is a feature available in
most board-level design editor.
 Layer Versus Schematic check is between
schematic and mask layout checking.

23. Verification tools (DRC, ERC, LVS) (pg 1-17)
ERC in Board-level editor
DRC in IC-mask layout editor

24. Waveform viewer (pg 1-18)
 When designing IC layout, timing of the circuit is
a very crucial consideration.
 For example, a longer metal routing means
slightly longer delay.
 So, you should check to make sure that those
additional delays do not result in the circuit not
performing according to the required function or
affects the noise immunity of the design.

25. PCB layout editor (pg 1-18)
 Two ways to use PCB layout editor.
 One is to design the circuit using component
available from the editors’ library.
 The other is to convert the designed circuit into
PCB mask layout to a level not possible with
manual drawing.
 Such precision had been crucial in design of
surface-mount PCB.

26. ECAD tools on the market (pg 1-20)
 Range of available ECAD tools on the market is
too wide and extensive to be made into a
comprehensive list.
 Below list some of the EDA tools according to
categories.

27. ECAD tools on the market (pg 1-20)

28. Critical review of ECAD Systems
 There are few critical areas of considerations
when choosing ECAD systems (pg 1-22):
 System requirement
 Ease of use
 Extensiveness of component library
 Range of simulation and verification tools provided
 Efficiency of simulation algorithm
 Possibility of importing from or exporting to other ECAD
software.

29. System requirement (pg 1-22)
 Software
 So far, the best ECAD software on the market are
made of UNIX operating system.
 It may not necessarily mean you have to change OS
in order to use an ECAD system.
 Would it benefit in the long run to invest in the state-of-
the art ECAD system, even if it meant changing the
OS of your workplace?
 Hardware
 Hardware requirement tend to be very demanding.

30. System requirement (pg 1-22)
 You should make sure your hardware could support all
the nice features available from ECAD software of
your choice.
 Also, you must decide whether your job requires high-
end features or not.

31. Ease of Use (pg 1-23)
 Some ECAD solution providers would have you believe
that features such as “schematic capture” or “drag-&-
drop” equate “ease of use”.
 But that is not necessarily the case.
 Take an example:
 For Multisim software, it is easy to search and use analogue
components.
 But for digital devices, this will be a big headache for the designer
as the Multisim categorized all the IC according to family like LS
family and LC family without much info.
 Unless the designer knows all the part numbers of all the IC, or
has a data book right next to him, else he will find it difficult to
even just search for a 4-bit binary counter.

32. Extensiveness of component library (pg 1-24)
 Any design you make eventually have to be built with
real parts.
 So, it is generally advisable that you design around what
available parts you have to avoid the high cost custom-
made components.
 And this would be so much easier to do if your
component library reflects the most up-to-date market
component range.
 Most ECAD packages nowadays allow users to
download net-lists of newly released components from
the internet to update their component library. This is a
very desirable feature.

33. Range of simulation tools provided, or range of
verification tools provided (pg 1-25)
 The rule is simple: the more the merrier.
 But of course, in some cases, more features
could spell higher cost.
 So, if you really do not need certain features,
you do not really have to buy the more
expensive ones with more features.
 It boils down again to your actual needs.

34. Efficiency of simulation algorithm (pg 1-25)
 The availability of simulation tools does not
necessarily mean they perform well or easy to
use.
 If possible, you should try out demonstration
versions of software before buying it to find out if
the simulation tools work as claimed.

35. Possibility of importing from or exporting
to other ECAD software (pg 1.25)
 It is good that the ECAD software you procure allows
importing from or exporting to the file formats of other
popular ECAD software.
 For example, the client of your company may not use the
same ECAD software as you are using.
 And it would then be very difficult for them to view your
samples if your ECAD software cannot exporting to your
customer file format.
 Also, the ability of importing is desirable in cases where
you have the opportunity to download existing net-list
from other file formats to incorporate into your own
design.

36. Assignment 1
 10% of the total coursework marks.
 Maximum 2 persons in a group.
 Provide the web address of information
gathered.
 Marks will be deduct if the lecturer finds out any
“KES TIRU-MENIRU”. In some case, zero marks
for the particular group of student.
 Cut-and-paste directly from the source, marks
will be deduct.