2003 Microchip Technology Inc. DS51419A
FilterLab
®
2.0
User’s Guide
M
DS51419A-page ii 2003 Microchip Technology Inc.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro
®
8-bit MCUs, K
EE
L
OQ
®
code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
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Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, K
EE
L
OQ
, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE and PowerSmart are registered trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
AmpLab, FilterLab, microID, MXDEV, MXLAB, PICMASTER,
SEEVAL and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Application Maestro, dsPICDEM, dsPICDEM.net, ECAN,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, microPort,
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,
PICkit, PICDEM, PICDEM.net, PowerCal, PowerInfo,
PowerMate, PowerTool, rfLAB, rfPIC, Select Mode,
SmartSensor, SmartShunt, SmartTel and Total Endurance are
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2003, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
2003 Microchip Technology Inc. DS51419A-page iii
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FilterLab
®
2.0
User’s Guide
Table of Conte nts
General Information
Introduction .......................................................................................... 1
About This Guide ................................................................................. 2
The Microchip Internet Web Site.......................................................... 2
Customer Support ................................................................................ 3
Chapter 1. Dialog Boxes
1.1 Dialog Boxes ................................................................................ 5
Chapter 2. Wizards
2.1 Anti-Aliasing Wizard ................................................................... 19
2.2 Filter Selection Wizard ............................................................... 25
Chapter 3. Toolbar
3.1 Buttons ....................................................................................... 35
3.2 Approximation Combo Box ........................................................ 38
3.3 Frequency Textboxes ................................................................. 39
Chapter 4. Menus
4.1 File ............................................................................................. 41
4.2 Edit ............................................................................................. 44
4.3 View ........................................................................................... 45
4.4 Filter ........................................................................................... 46
4.5 Window ...................................................................................... 47
4.6 Help ............................................................................................ 47
FilterLab
®
2.0 User’s Guide
DS51419A-page iv
2003 Microchip Technology Inc.
Chapter 5. Window Views
5.1 Frequency View ..........................................................................49
5.2 Circuit View .................................................................................50
5.3 Spice Listing View ......................................................................51
Appendix A. FilterLab 2.0 to SPICE Interface
A.1 Introduction And Highlights......................................................... 53
Appendix B. Filter Magnitude Templates
B.1 Introduction................................................................................. 57
Appendix C. Group Delay
C.1 Introduction................................................................................. 63
Appendix D. Bessel Filter Response
D.1 Introduction................................................................................. 65
Appendix E. Op Amp Selection
E.1 Introduction................................................................................. 67
Appendix F. Selected References
F.1 Introduction................................................................................. 71
Worldwide Sales and Service ................................................................. 72
2003 Microchip Technology Inc. DS51419A-page 1
M
FilterLab
®
2.0
User’s Guide
General Information
INTRODUCTION
FilterLab
®
2.0 is an innovative software tool that simplifies active filter design. Available
at no cost from Microchip’s web site (www.microchip.com), the FilterLab 2.0 active filter
software design tool provides full schematic diagrams of the filter circuit with
recommended component values and displays the frequency response.
FilterLab 2.0 allows the design of low-pass filters up to an 8th order filter with Cheby-
chev, Bessel or Butterworth responses from frequencies of 0.1 Hz to 1 MHz. FilterLab
2.0 also can be used to design band-pass and high-pass filters with Chebychev and
Butterworth responses. The circuit topologies supported by FilterLab 2.0 are the Sallen
Key and Multiple Feedback (MFB). The low-pass filters can use either the Sallen Key
or MFB, the band-pass is available with the MFB and the high-pass uses the Sallen
Key.
Users can select a flat pass band or sharp transition from pass band to stopand.
Options (such as minimum ripple factor, sharp transition and linear phase delay) are
available. Once the filter response has been identified, FilterLab 2.0 generates the fre-
quency response and the circuit. For maximum design flexibility, changes in capacitor
values can be implemented to fit the demands of the application. FilterLab 2.0 will
recalculate all values to meet the desired response, allowing real-world values to be
substituted or changed as part of the design process.
FilterLab 2.0 also generates a SPICE model of the designed filter. Extraction of this
model will allow time domain analysis in SPICE simulations, streamlining the design
process.
Further consideration is given to designs used in conjuction with an Analog-to-Digital
Converter (ADC). A suggested filter can be generated by simply inputting the bit
resolution and sample rate via the Anti-Aliasing Wizard. This eliminates erroneous
signals folded back into the digital data due to the aliasing effect.
This section also covers the following topics:
• About This Guide
• The Microchip Internet Web Site
• Customer Support