Microchip Technology Active Filter Demo Board Kit User guide

Active Filter Demo Board Kit

User’s Guide

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ACTIVE FILTER DEMO BOARD KIT

USER’S GUIDE

Table of Contents

Preface ........................................................................................................................... 1

Introduction............................................................................................................ 1

Document Layout .................................................................................................. 1

Conventions Used in this Guide ............................................................................ 2

Recommended Reading........................................................................................ 3

The Microchip Web Site ........................................................................................ 3

Customer Support ................................................................................................. 3

Document Revision History ................................................................................... 3

Chapter 1. Product Overview ....................................................................................... 5

1.1 Introduction ..................................................................................................... 5

1.2 Kit Contents .................................................................................................... 5

1.3 Intended Use of the Active Filter Demo Board Kit .......................................... 6

1.4 Active Filter Demo Board Kit Description ....................................................... 6

1.5 Sub-assemblies .............................................................................................. 6

1.6 Associated Tools ............................................................................................ 8

Chapter 2. Setup and Installation ................................................................................ 9

2.1 Introduction ..................................................................................................... 9

2.2 Required Tools ............................................................................................... 9

2.3 Connecting the PCBs ..................................................................................... 9

2.4 V

2.5 Active Filter Section Set-up .......................................................................... 11

2.6 Set-up Verification ........................................................................................ 17

/2 Filter Section Set-up .......................................................................... 10

Chapter 3. Building the Filter Supplied in the Kit .................................................... 19

3.1 Introduction ................................................................................................... 19

3.2 The Filter Design .......................................................................................... 19

3.3 Putting the Filter Together ............................................................................ 20

3.4 Testing the Filter ........................................................................................... 21

Chapter 4. Common Filter Modifications .................................................................. 25

4.1 Introduction ................................................................................................... 25

4.2 Power Supplies ............................................................................................ 25

4.3 Filter Section Ordering for Noise and Headroom ......................................... 27

4.4 Combining Low-pass and High-pass Sections ............................................. 27

4.5 Higher Frequency Filters .............................................................................. 27

4.6 Using 8-Pin SOIC Op Amps ......................................................................... 28

Active Filter Demo Board Kit User’s Guide

Appendix A. Schematics and Layouts ......................................................................31

A.1 Introduction .................................................................................................. 31

A.2 V

A.3 Active Filter Section (Sub-Assembly #: 102-00097R1) ................................ 34

A.4 Accessory Bag (Sub-Assembly #: 110-00097R1) ........................................ 37

Appendix B. Bill Of Materials (BOM) ..........................................................................39

B.1 VDD/2 Filter Section BOMs .......................................................................... 39

B.2 Active Filter Section BOM ............................................................................ 40

B.3 Accessory Bag BOM .................................................................................... 41

Worldwide Sales and Service .....................................................................................42

/2 Filter Section (Sub-Assembly #: 102-00098R1) ................................ 31

ACTIVE FILTER DEMO BOARD KIT

USER’S GUIDE

Preface

NOTICE TO CUSTOMERS

All documentation becomes dated, and this manual is no exception. Microchip tools and documentation are constantly evolving to meet customer needs, so some actual dialogs and/or tool descriptions may differ from those in this document. Please refer to our web site (www.microchip.com) to obtain the latest documentation available.

Documents are identified with a “DS” number. This number is located on the bottom of each page, in front of the page number. The numbering convention for the DS number is “DSXXXXXA”, where “XXXXX” is the document number and “A” is the revision level of the document.

For the most up-to-date information on development tools, see the MPLAB Select the Help menu, and then Topics to open a list of available on-line help files.

IDE on-line help.

INTRODUCTION

This chapter contains general information that will be useful to know before using the Active Filter Demo Board Kit. Items discussed in this chapter include:

• Document Layout

• Conventions Used in this Guide

• Recommended Reading

• The Microchip Web Site

• Customer Support

• Document Revision History

DOCUMENT LAYOUT

This document describes how to use the Active Filter Demo Board Kit. The manual layout is as follows:

• Chapter 1. “Product Overview” - Important information about the Active Filter

Demo Board Kit.

• Chapter 2. “Setup and Installation” – Covers the initial set-up of the Active

Filter Demo Board Kit. It lists the required tools, shows how to connect the boards and demonstrates how to verify the set-up.

• Chapter 3. “Building the Filter Supplied in the Kit” – Discusses the filter sup-

plied in the kit (loose parts in a separate bag). Its design, component placement, and testing are discussed.

• Chapter 4. “Common Filter Modifications” – Covers modifications that are

easy to do with these boards. It also discusses common filter limitations.

• Appendix A. “Schematics and Layouts” – Shows the schematic and board

layouts for the Active Filter Demo Board Kit.

• Appendix B. “Bill Of Materials (BOM)” – Lists the parts used to build the

sub-assemblies in the Active Filter Demo Board Kit.

Active Filter Demo Board Kit User’s Guide

CONVENTIONS USED IN THIS GUIDE

This manual uses the following documentation conventions:

DOCUMENTATION CONVENTIONS

Description Represents Examples

Arial font:

Italic characters Referenced books MPLAB® IDE User’s Guide

Emphasized text ...is the only compiler...

Initial caps A window the Output window

A dialog the Settings dialog A menu selection select Enable Programmer

Quotes A field name in a window or

dialog

Underlined, italic text with right angle bracket

Bold characters A dialog button Click OK

N‘Rnnnn A number in verilog format,

Text in angle brackets < > A key on the keyboard Press <Enter>, <F1>

Courier New font:

Plain Courier New Sample source code #define START

Italic Courier New A variable argument file.o, where file can be

Square brackets [ ] Optional arguments mcc18 [options] file

Curly brackets and pipe character: { | }

Ellipses... Replaces repeated text var_name [,

A menu path File>Save

A tab Click the Power tab

where N is the total number of digits, R is the radix and n is a digit.

Filenames autoexec.bat File paths c:\mcc18\h Keywords _asm, _endasm, static Command-line options -Opa+, -Opa- Bit values 0, 1 Constants 0xFF, ‘A’

Choice of mutually exclusive arguments; an OR selection

Represents code supplied by user

“Save project before build”

4‘b0010, 2‘hF1

any valid filename

[options]

errorlevel {0|1}

var_name...]

void main (void) { ... }

THE MICROCHIP WEB SITE

Microchip provides online support via our web site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information:

• Product Support – Data sheets and errata, application notes and sample

programs, design resources, user’s guides and hardware support documents, latest software releases and archived software

• General Technical Support – Frequently Asked Questions (FAQs), technical

support requests, online discussion groups, Microchip consultant program member listing

• Business of Microchip – Product selector and ordering guides, latest Microchip

press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives

Preface

CUSTOMER SUPPORT

Users of Microchip products can receive assistance through several channels:

• Distributor or Representative

• Local Sales Office

• Field Application Engineer (FAE)

• Technical Support

• Development Systems Information Line

Customers should contact their distributor, representative or field application engineer for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document.

Technical support is available through the web site at: http://support.microchip.com

DOCUMENT REVISION HISTORY

Revision A (June 2006)

• Initial Release of this Document.

Active Filter Demo Board Kit User’s Guide

NOTES:

Chapter 1. Product Overview

1.1 INTRODUCTION

The Active Filter Demo Board Kit is described by the following:

• Assembly # : 114-00097R1

• Order # : MCP6XXXDM-FLTR

• Name: Active Filter Demo Board Kit

Items discussed in this chapter include:

• Kit Contents

• Intended Use of the Active Filter Demo Board Kit

• Active Filter Demo Board Kit Description

• Sub-Assemblies

• Associated Tools

1.2 KIT CONTENTS

ACTIVE FILTER DEMO BOARD KIT

USER’S GUIDE

•VDD/2 Filter Section Board - One partially assembled board

• Active Filter Section – Four partially assembled boards

• Important Information “Read First”

• Accessory Bag - contains loose parts for populating sockets on boards

• Analog and Interface Products Demonstration Boards CD-ROM (DS21912) – This CD-ROM contains the files and literature mentioned in this user’s guide

FIGURE 1-1: Active Filter Demo Board Kit Contents.

Active Filter Demo Board Kit User’s Guide

1.3 INTENDED USE OF THE ACTIVE FILTER DEMO BOARD KIT

This kit is intended to support active filters designed by FilterLab®V2.0 (see Section 1.6 “Associated Tools”). These filters are all pole and are built by cascading first and second order sections.

Higher frequency filters (e.g., a low-pass filter with cutoff at 1 MHz) can have their design initially verified on these boards; see Section 4.5 “Higher Frequency Filters”.

1.4 ACTIVE FILTER DEMO BOARD KIT DESCRIPTION

The Printed Circuit Boards (PCB) in the Active Filter Demo Board Kit have the following features:

• All filter resistors and capacitors are socketed

• Supports all Microchip single op amps

- PDIP-8 package (e.g., MCP6271) are socketed

- SOIC-8 package can be accomodated; see Section 4.6 “Using 8-Pin SOIC

Op Amps”

• Test points for connecting lab equipment

• Single supply configuration

• Modularized connection scheme

1.5 SUB-ASSEMBLIES

The Active Filter Demo Board Kit is comprised of three sub-assemblies:

•V

/2 Filter Section

- Sub-Assembly # : 102-00098R1

- One PCB designed to provide mid-supply biasing to the other PCBs

- Provides power supply test points for a lab power supply

- Provides input test points for a lab signal generator

• Active Filter Sections

- Sub-Assembly # : 102-00097R1

- Four PCBs designed to be cascaded

- Support filter orders between n = 1 and n = 8

- Provide output test points for lab equipment

• Accessory Bag

- Sub-Assembly # : 110-00097R1

- Kit of resistors, capacitors, and op amps that can be used to build the filter circuit in Figure 2-8

Product Overview

Figure 1-2 shows the Active Filter Demo Board Kit’s five PCBs; one VDD/2 Filter Section PCB and four Active Filter Section PCB’s. It shows how these boards are cascaded (using board connectors), and how lab equipment can be attached (via test points) to measure the filter response.

Power Supply

VDD/2

Filter

Section

3 3 3 3 33

Active

Filter

Section

Active

Filter

Section

Signal Generator

FIGURE 1-2: Measurement Setup Block Diagram.

Figure 1-3 shows the block diagram of the V

/2 Filter Section, and Figure 1-4 shows

the block diagram of the Active Filter Sections.

Power

Supply

Signal

Input

VDD/2

GND

GND GND

GND

Supply Test Points

(INT or EXT)

Single Op Amp

(buffers the internal

VDD/2 Source)

Select

/2 Source

Active

Filter

VDD/2

GND

OUT

GND

Signal Analyzer

Active

Filter

Section

Power Supply OutputInput

Signal Output

Signal Input

Tes t P o in t s

FIGURE 1-3: V

Power

Supply

VDD/2

/2 Filter Section Block Diagram.

Single

Op Amp

Signal Output

Te s t P oi n t s

GND

Signal

Input

GND GND

Resistor and

Capacitor

Sockets

GND

FIGURE 1-4: Active Filter Section (4 each) Block Diagram.

VDD/2

GND

OUT

GND

Power Supply OutputInput

Signal Output

Active Filter Demo Board Kit User’s Guide

1.6 ASSOCIATED TOOLS

FilterLab 2.0® is an innovative software tool that simplifies active (op amp) 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 component values, displays the frequency response, and gives a SPICE listing for further simulations. Users can select a low-pass, band-pass or high-pass response. Available functions are Bessel, Butterworth, and Chebyshev, with order between n = 1 and 8.

Chapter 2. Setup and Installation

2.1 INTRODUCTION

This chapter shows how to set up the Active Filter Demo Board Kit. Items discussed in this chapter include:

• Required Tools

• Connecting the PCBs

•V

/2 Filter Section Set-up

• Active Filter Section Set-up

• Set-up Verification

2.2 REQUIRED TOOLS

• Lab power supply

• Lab signal source (e.g., function generator)

• Lab measurement equipment (e.g., oscilloscope)

ACTIVE FILTER DEMO BOARD KIT

USER’S GUIDE

2.3 CONNECTING THE PCBs

This section discusses the primary method for setting up the Active Filter Demo Board Kit. An exploded view of how the different boards connect is shown in Figure 2-1 (see also Figure 1-2).

The filter order will determine how many of the Active Filter Section boards need to be cascaded (one board when n = 1 or 2, two boards when n = 3 or 4,

The board edge connectors are slid together to make good electrical connection between boards.

The (surface mount) test points allow lab equipment to be connected to these boards. The user provides the input signal and power to the V the output signal at the last Active Filter Section.

Lab Power Supply

…).

/2 Filter Section, and measures

Oscilloscope

Function Generator

FIGURE 2-1: Board Connections for the Active Filter Demo Board Kit.

VDD/2 Filter Section

Active Filter Section

Active Filter Demo Board Kit User’s Guide

The user provides the supply voltages, which need to be in the allowed range for the installed op amps. Any of Microchip’s op amps that operate below 5.5V can be used; higher voltage parts can be accommodated (see Section 4.2 “Power Supplies”). Five MCP6271 op amps are included in the accessory bag for convenience.

The power lines are bypassed by 1.0 µF capacitors at each board input. The op amps also have 0.1 µF local bypass capacitors.

2.4 VDD/2 FILTER SECTION SET-UP

Figure 2-2 gives the circuit diagram for the VDD/2 Filter Section. It allows the mid-supply voltage (V at INT) by the on-board op amp (U flexibility in setting up a filter circuit.

/2) to be set by an external power supply (JP1 at EXT), or internally (JP1

). The headers and test points allow the user

GND

1.0 µF

1.0 µF EXT

INT

0.1 µF

MCP6271

0.1 µF

20 kΩ

VDD/2

GND

VDD/2

GND

OUT

GND

FIGURE 2-2: VDD/2 Filter Section Circuit.

The V

/2 Filter Section PCB is shown in Figure 2-3. The single op amp U1 can have

either a PDIP-8 or SOIC-8 package:

• PDIP-8 packages are inserted into the DIP-8 socket above the U1 label

• SOIC-8 packages can be accommodated; see Section 4.6 “Using 8-Pin SOIC

Op Amps”

• Only one op amp can be connected at a time

Select the mid-supply power source by setting jumper JP1 to (see Figure 2-3):

• Internal V

- Op amp U1 drives the V

-The V

• External V

/2 (INT on bottom)

/2 line on all of the PCBs

/2 line must be disconnected from any power supply (at P1 or TP4)

/2 (EXT on top, as shown)

- Op amp U1 has no load

-The V

/2 line must be connected to an external supply voltage (at P1 or

TP4)

The headers P1 and J1 on the left of the board are unpopulated (see Figure 2-3):

• The test points TP1 through TP5 provide connections for the same voltages

• P1 and J1 can be populated by the user, if desired, to connect to another (user provided) board on the left

+ 32 hidden pages

Microchip Technology Active Filter Demo Board Kit User guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Preface

INTRODUCTION

DOCUMENT LAYOUT

CONVENTIONS USED IN THIS GUIDE

RECOMMENDED READING

THE MICROCHIP WEB SITE

CUSTOMER SUPPORT

DOCUMENT REVISION HISTORY

Chapter 1. Product Overview

1.1 INTRODUCTION

1.2 KIT CONTENTS

1.3 INTENDED USE OF THE ACTIVE FILTER DEMO BOARD KIT

1.4 ACTIVE FILTER DEMO BOARD KIT DESCRIPTION

1.5 SUB-ASSEMBLIES

1.6 ASSOCIATED TOOLS

Chapter 2. Setup and Installation

2.1 INTRODUCTION

2.2 REQUIRED TOOLS

2.3 CONNECTING THE PCBs

2.4 VDD/2 FILTER SECTION SET-UP