LTpowerCAD II Quick Start Guide Datasheet by Analog Devices Inc.
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LTpowerCADTM II
Introduction & Quick Start Guide
Rev. 2.0 07/2013
Design Tool Development Team
Power Products, Linear Technology Corp.
Copyright © 2013 Linear Technology. All rights reserved
LTpowerCAD@Linear.com

2
What is LTpowerCAD Design Tool
A Com
p
lete
,
Ste
p
-b
y
-Ste
p
Power Su
pp
l
y
Desi
g
n Tool:
p,p
y
pppyg
Step-by-Step Power Supply Design:
Enter specs, Power Supply LTspiceTM
Efficienc
y
& Loo
p
Stabilit
y
search solution. Schematic. Simulation
y
Power Loss
py
& Transient
LTpowerCAD
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

3
How is LTpowerCAD Different from LTspice:
LT i
Afliit
iltitl
ith i t t d d l f t
LT
sp
i
ce:
A
power
f
u
l
c
i
rcu
it
s
i
mu
l
a
ti
on
t
oo
l
w
ith
i
n
t
egra
t
e
d
mo
d
e
l
s o
f
mos
t
Linear Technology products.
LTpowerCAD Design Tool :
• A power supply design tool instead of simulation tool.
•Searches for a solution / LTC part for given power supply spec.
• Guides users to select power stage components.
• Provides detailed power efficiency / loss analysis.
• Provide quick loop bode plot stability and load transient analysis.
• Only supports selected power products (mostly buck & modules).
•Desi
g
n file can be ex
p
orted into LTs
p
ice simulation circuit.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
gp
p

4
How to get your free LTpowerCAD II
•Go to http://www.linear.com/LTpowerCAD
• Download & install LTpowerCAD II on your Windows PC.
• See later pages for installation instruction.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

5
LTpowerCAD II 2.0 Supported Parts
Buck Converters :
Note:
Note:
This list was generated on
07/25/2013. New parts could be
added to the library after that. Click
“S
y
nc-Release” to u
p
date
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
y
p
LTpowerCAD library & functions.

6
LTpowerCAD II 2.0 Supported Parts
Boost Converters :
Buck-Boost Converters :
Note:
This list was generated on
06/06/2013. New parts could be
added to the library after that. Click
“Sync-Release” to update
LT
p
owerCAD librar
y
& functions.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
py

7
I. Installation
LTpowerCAD
II
LTpowerCAD
II
Software Installation
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

8
Minimum Requirements
9PC with Microsoft Windows XP SP2 or later OS
The following system and software is required for LTpowerCAD II v2.0 TM
9Microsoft Office Excel 2000, 2003, 2007, 2010 or 2013
9Microsoft .NET Framework 3.5 SP1, 4.0 or Higher
htt
p
://www.microsoft.com/net/download
9Microsoft SQL Server Compact 3.5 Service Pack 2
http://www.microsoft.com/en-us/download/details.aspx?id=5783
p
*
Note : The LTpowerCAD installer is made to
automatically download and
**
Note:
Note
:
The
LTpowerCAD
installer
is
made
to
automatically
download
and
install these the Microsoft .NET and SQL Server to your system if your
system does not already have these installed. However, if for some reason
they are not installed automatically, you need to install them manually from
Microsoft download sites.
Note:
•Windows Vista or Windows 7, Windows 8 based PC has .NET Framework integrated.
•Some Windows XP based PC may need additional installation of the .NET Framework, which can be
freely downloaded at www.microsoft.com.
•Man
y
new com
p
uters ma
y
alread
y
have SQL Server Com
p
act 3.5SP2 installed
(
check to make sure
)
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
ypyy p ( )
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

9
Minimum Requirements (cont’d)
Optional: check if .NET and SQL Server are installed:
Microsoft .NET 3.5, 4 or
higher is required
Required for accessing
part information
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

10
Installing LTpowerCAD II v2.0TM
1. Double Click “Setu
p
.exe” to Start LT
p
owerCAD II v2.0TM Desi
g
n Tool Setu
p
Wizard
p
p
gp
Note : Do not install by double clicking the “MS.msi” file as this will prevent the installer from checking to install and installing any
missing Microsoft requirements.
2. Click “Next”
3. Select Installation Folder and Click “Next”
4. Click “Next” to Confirm Installation and then “Close” to complete the Installation
Click “Next” Select Folder Click “Next” Click “Close”
5. Check the contents of the installation folder (see next slide)
Click “Next”
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
Note : The installation will place shortcuts to the LTpowerCAD II v2.0
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

11
II. User Interface
Gettin
g
Start with LT
p
owerCAD II
g
p
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

12
Main Page
Search for a part based on supply spec. and
requirements
Open an existing LTpowerCAD II design file
Open an existing Excel-Based design file
Vi h l fil
Vi
ew
h
e
l
p
fil
e
View LTC Sales Office contacts
Update LTpowerCAD II program & program library
Open LTC Toolbox
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

13
Search Page
Step 2 Click “Search”
Step 1. Enter power
supply spec. and
required functions.
Step
2
.
Click
“Search”
after the supply specs
are entered to find
parts.
If you know the LT part# to use,
you can enter the 4-digit part#
and click “go” instead of search.
Step 3. Select a Part from
Search Results Table:
Click LTC icon for LTpowerCAD II tool
Click Excel icon for Excel-Based tool
Note: if the icon is in grey
color, it means the design
tool is not available.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

14
Available Design Tool Formats
Two possible design
tool formats:
1. Non-Excel
LTpowerCAD
Design
LTpowerCAD
Design
Tool:
If available, an
active LTC button is
h
s
h
own:
2. Excel-Based
Design Tool:
Design
Tool:
If available, an
active Excel button
is shown:
Note: if the icon is in
grey color, it means
the design tool is not
il bl t
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
ava
il
a
bl
e ye
t
.

15
Step-By-Step Supply Design Procedure
using the LTpowerCADTM Design Tool
Enter Supply Spec.
Main
program
Search/select a part
Automatic spec transfer
Idiid l
Open the design tool
Power stage design
Com
p
onent
I
n
di
v
id
ua
l
Design Tool
Libraries
Power
stage
design
p
libraries
Control loo
p
o
p
timization Check load step
(if d d)
pp
(if
nee
d
e
d)
Export to and run
LT i ™ i l ti
View la
y
out
LTspice™ simulator
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved 15
LT
sp
i
ce
™
s
i
mu
l
a
ti
on
file
y
example
(OPT)

16
Exam
p
le of a non-Excel LT
p
owerCAD desi
g
n
p
p
g
Tool
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

17
Design Step 1 – Power Stage Design
Yellow Cells = Suggested values or calculated parameters
Bl C ll U ’ h l
Design Requirements & Part Limits
Bl
ue
C
e
ll
s =
U
ser
’
s c
h
osen va
l
ues
Red Cells = Warning - parameter outside of recommended range.
Select different current sensing schemes
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
•User can only change blue-cell values and check calculated circuit parameters in yellow and red cells.
•Red cells are for warnings. User needs to decide if following/correcting the warning or not.

18
Design Step 2– Select L and FET, Optimize Eff % & Power Loss
Enter power stage component details & Test Conditions (enter manually or select from built-in library)View data for each rail
Click “Update
Plots” after
component value
changes.
Estimated Efficiency & Power Loss Curves
with Data Point Cursors Double
click to set
Estimated Power Loss Breakdown
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
with
Data
Point
Cursors
.
Double
-
click
to
set
axes Preferences
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

19
Power Component Library - FET
Click “Select” to open MOSFET library.
Standard
library
User
User
created
library
User can
add new
add
new
part into
user
library
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
Popular vendor weblinks

20
Power Component Library - Inductor
Click “Select” to open inductor library.
Standard
library
User
User
created
library
User can
add new
add
new
part into
user
library
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
Popular vendor weblink / web-search site.

21
Design Step 3 – Optimize Loop Comp & Load Transient
Enter component details (enter manually or select from built-in library)
View data for each rail View Loop Gain, Feedback gain, Output Impedance, Control to Output, Compensator plots
C
apacitor
library
library
Loop Gain, Feedback, Output
Load Transient Estimation plots
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Loop
Gain,
Feedback,
Output
Impedance, Ith to Vout, and
Compensator plots
Load
Transient
Estimation
plots
Import plot data from data file (ie Ridley
AP300) or Export data to data file or Excel.
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

22
(Optional) Design Step 4 – Export to LTspice for Simulation
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

23
Bench Verified Loop and Load Transient Model
•
In the design tool the small signal
Voltage Loop Gain
80 150
•
In
the
design
tool
,
the
small
signal
model of every part has been verified
on LTC standard demo board.
• It remains the user’s responsibility to
verify his calculated result with bench
20
40
60
u
de(dB)
15
60
105
e
(deg)
verify
his
calculated
result
with
bench
prototype.
-20
0
20
Magnit
u
-75
-30
15
Phas
e
Load Transient Approximation
70
90
Load Transient Approximation
70
90
-40
0.1 1 10 100 1000
Frequency(KHz)
-120
-10
10
30
50
-20 0 20 40 60 80
Time(usec)
Vo(t) (mV)
Load Transient Approximation
-
70
-50
-30
-10
10
Vo(t) (mV)
-10
10
30
50
-20 0 20 40 60 80
Time(usec)
Vo(t) (mV)
Load Transient Approximation
-
70
-50
-30
-10
10
Vo(t) (mV)
Mag mag_Exp Phase Ph_Exp
-90
70
-20 0 20 40 60 80
Time(usec)
-90
70
-20 0 20 40 60 80
Time(usec)
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved

24
Exam
p
le of a Excel-Based desi
g
n Tool
p
g
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

25
Step 1: Power Components Selection
In the design spreadsheet, power components design is guided
with schematic interface:
Values in yellow cells are calculated
/ recommended by design tool
/
recommended
by
design
tool
.
Values in blue cells are selected
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved 25
/ entered by user.

26
Power Stage Performances
CIN RMS
Current
Peak Inductor
Current
St d d V
Real Vo value
RED fonts give
St
an
d
ar
d
V
o
setting resistor
values
Real
Vo
value
and ripples
“warnings” of
undesirable design
values
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
26

27
Step 2: Control Loop Optimization
In the design spreadsheet, control loop design can be fine tuned:
Sliding bar for compensation adjustment.
Loop gain
Output
Loop
gain
prediction
Output
Impedance
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
Load transient
prediction

28
Additional Feature (1):
Export to & Run LTspice™ Simulation
In the design spreadsheet, click the “Export To LTspice” button:
If the LTspice™ simulator is installed,
it will be automatically opened:
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
Link to down load free LTSpice™ simulator:
http://www.linear.com/designtools/software/ltspice.jsp

29
Additional Feature (2):
Summary of design: BOM, size, cost and stress
In the design spreadsheet, click the “Summary” sheet:
P
P
ower
components
summary
Stress analyses
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved 29

30
LTpowerCAD II
Any feedback comments on the program or issues encountered are welcome!
Please forward your comments to the addresses below.
LTpowerCAD@Linear.com
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

31
Appendix
LTpowerCAD II v2.0TM
Installation
Installation
Troubleshooting
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential

32
Appendix : Installation Troubleshooting
I. Microsoft SQL Server Compact 3.5 SP2 ENU requirement :
1) Possible issue: Microsoft SQL Server Compact 3.5 SP2 is requirement missing
LTpowerCAD II v2.0 requires Microsoft SQL Server Compact 3.5 SP2 to access the internal parts database. If
this is not installed, the program may have issues accessing information for parts included in the program. An
example screenshot is shown below where this type of error has occurred. If this is confirmed to be installed on
t k it i t ll d tl hi h i i f th i t ll ti
your sys
t
em, ma
k
e sure
it
was
i
ns
t
a
ll
e
d
correc
tl
y w
hi
c
h
may requ
i
re a repa
i
r o
f
th
e
i
ns
t
a
ll
a
ti
on or new
installation of this requirement.
* Example shown above is on Windows XP
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Important : Make sure you installed using “setup.exe” file (not the MS.msi file)
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

33
Possible issue solution:
Check the programs you have currently installed on your system to see if Microsoft SQL Server Compact 3.5 SP2
requirement is missing or not The
LTpowerCAD
II v2 0 installer automatically checks if you have this requirement if not it
Appendix : Installation Troubleshooting
requirement
is
missing
or
not
.
The
LTpowerCAD
II
v2
.
0
installer
automatically
checks
if
you
have
this
requirement
,
if
not
it
will download and install it automatically. This can also be freely downloaded at Microsoft at http://www.microsoft.com/en-
us/download/details.aspx?id=5783 If this is confirmed to be installed on your system, make sure it was installed correctly
which may require a repair of the installation or new installation of this requirement.
Step 1) Check the list of programs you have currently installed on your system by
going to Start Menu ÆControl Panel ÆUninstall a program Step 2) If this is not installed, this can be downloaded from
http://www.microsoft.com/en-us/download/details.aspx?id=5783 . Please download
and install this package, then try to
un-install / re-install LTpowerCAD II v2.0.
** Note : The installer is made to automatically
download and install these software requirements
to your system if your system does not already
have these installed.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Important : Make sure you installed using “setup.exe” file (not the MS.msi file)
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

34
II. Microsoft Security Settings :
Appendix : Installation Troubleshooting
2) Possible issue: Microsoft Security Settings
Security default settings may prevent access of LTpowerCAD II v2.0 from its database causing an error
message to pop up when searching for a part (see below).
** Note : The installer is made to automatically set
up these folder settings. If for some reason you are
still getting a similar error please read through the
following slides to make sure.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Important : Make sure you installed using “setup.exe” file (not the MS.msi file)
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

35
Possible issue solution:
Appendix : Installation Troubleshooting
Run the program with an Administrator account , or try to modify your system’s Users account security settings
for now (see below).
St 1)
St
ep
1)
Go to the LTC folder location: (ie C:\Program Files (x86)
\
LTC)
Step 2) Right click on the LTpowerCAD 2 program folder ÆProperties
Step 3) Click on the Security tab. Click on your Administrators account and see
that the permissions should show Allow for all options (except for Special
permissions). The SYSTEM account should also have the same settings.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Important : Make sure you installed using “setup.exe” file (not the MS.msi file)
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.

36
Possible issue solution (cont’d):
Appendix : Installation Troubleshooting
Step 4) Click on your Users account to see the user settings. Your user account
may not have the permissions set (like shown below) that are needed. You can
change these in the next step.
Step5) Click on the Edit button and click on your Users account again and click the
check boxes on the Allow column for Full control, Modify, Write. Click OK. The
settings should now be the same as you saw for the Administrators account.
LTpowerCADTM Design Tool Quick Start Guide Copyright © 2010 Linear Technology. All rights reserved
LTC Confidential
Important : Make sure you installed using “setup.exe” file (not the MS.msi file)
LTpowerCAD II v2.0TM Design Tool Quick Start Guide Copyright © 2013 Linear Technology. All rights reserved.
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