Microchip Technology MCP1601 User Manual

M

MCP1601

Evaluation Board

User’s Guide

 2003 Microchip Technology Inc. DS51315A

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 ar e 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.

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and may be superseded by updates.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 use or
otherwise. Use of Microchip’s products as critical components in
life support systems is not authorized except with express
written approval by Microchip. No licenses are conveyed,
implicitly or otherwise, under any intellectual property rights.

Trademarks

The Microchip name and logo, the Micr ochip logo, K

EELOQ

,
MPLAB, PIC, PICmicro, PICSTART, PRO MATE and
PowerSmart are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.

FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are registered
trademarks of Microchip Technology Incorporated in the U.S.A.

Accuron, dsPIC, dsPICDEM.net, ECONOMONITOR,
FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming,
ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB,
MPLINK, MPSIM, PICC, PICkit, PICDEM, PICDEM.net,
PowerCal, PowerInfo, PowerTool, 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 pape r.

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
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog produ cts. In
addition, Microchip’s qua lity system for the
design and manufacture of development
systems is ISO 9001 certified.

®

8-bit MCUs, KEEL

®

code hopping

OQ

DS51315A - page ii  2003 Microchip Technology Inc.

MCP1601 Eval. Board

M

User Guide

Table of C o ntents

General Information .................................................................................. 1

Introduction And Highlights.................................................................. 1

About This Guide..................................................................................1

The Microchip Internet Web Site...........................................................2

Customer Support.................................................................................2

Chapter 1. MCP1601 Evaluation Board ...............................................3

1.1 Introduction ................................................................................ 3

1.2 Detailed Description .................................................................. 4

1.3 Test Points ................................................................................ 6

Appendix A. Schematic and Board Layouts ......................................... 7

A.1 Introduction................................................................................ 7

A.2 Evaluation Board Schematic ................................................... 8

A.3 Evaluation Board - Silk Screen Layer ...................................... 8

A.4 Evaluation Board - Top Metal Layer ........................................ 9

A.5 Evaluation Board - Bottom Metal Layer ................................... 9

Appendix B. Bill Of Materials (BOM).................................................... 11

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2002 Microchip Technology Inc. DS51315A-page iii

MCP1601 Eval. Board User Guide

NOTES:

DS51315A-page iv



2002 Microchip Technology Inc.

MCP1601 Eval. Board

M

General Information

INTRODUCTION AND HIGHLIGHTS

This section contains general information that will be useful to know before using the
MCP1601 Evaluation Board.

This section covers the following topics:

• About this Guide

• Recommended Reading

• The Microchip Internet Web Site

• Customer Support

ABOUT THIS GUIDE

Document Layout

This document describes how to use the MCP1601 Evaluation Board.

The User’s Guide layout is as follows:

• Chapter 1: MCP1601 Evaluation Board - For user’s evaluating the MCP1601
device, this section describes how to use the various features of the board.

User Guide

Appendices

• Appendix A: Schematic and Board Layout – shows the schematic and Printed
Circuit Board (PCB) layout diagrams for the MCP1601 Evaluation Board.

- Appendix A.1 gives some overview and highlight information.

- Appendix A.2 contains the Evaluation Board Schematic

- Appendix A.3 shows the Silk Screen Layer of the PCB.

- Appendix A.4 shows the Silk Screen and Top Metal Layer of the

PCB.

- Appendix A.5 shows the Silk Screen and Bottom Metal layer of the

PCB.

• Appendix B: Bill of Materials – Table B-1 shows the Bill of Materials (BOM) for
the PCB.

• Worldwide Sales and Service – gives the address, telephone and fax number
for Microchip Technology Inc. sales and service locations throughout the world.

Recommended Reading

For more information regarding the MCP1601 device, the following is recommended
reading:

MCP1601 Data Sheet (DS21762)

This data sheet provides detailed information regarding the MCP1601 500 mA Syn­chronous BUCK Regulator. The data sheet is available for download from our World
Wide Web Site (www.microchip.com) or from the Technical Library CD-ROM
(DS00161).

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2003 Microchip Technology Inc. DS51315A-page 1

MCP1601 Eval. Board User Guide

THE MICROCHIP INTERNET WEB SITE

Microchip provides easy access to our documentation and on-line support through our
World Wide Web Site at www.microchip.com. You can download files from the web site
or from our FTP site at ftp://ftp.microchip.com

CUSTOMER SUPPORT

Users of Microchip products can receive assistance through several channels:

• Distributor or Representative

• Local Sales Office

• Field Application Engineer (FAE)

• Corporate Applications Engineer (CAE)

• Hot line

Customers should call their distributor, representative or field application engineer
(FAE) for support. Local sales offices are also available to help customers. See the
back cover for a listing of sales offices and locations.

Corporate Applications Engineers (CAEs) may be contacted at [phone].

In addition, there is a Systems Information and Upgrade Line. This line provides system
users a listing of the latest versions of all of Microchip's development systems software
products. Plus, this line provides information on how customers can receive any cur­rently available upgrade kits.

The Hot Line Numbers are:

• 1-800-755-2345 for U.S. and most of Canada, and

• 1-480-792-7302 for the rest of the world

DS51315A-page 2

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2003 Microchip Technology Inc.

MCP1601 Eval. Board

M

Chapter 1. MCP1601 Evaluation Board

1.1 INTRODUCTION

The MCP1601 Evaluation Board is designed to demonstrate the use of the MCP1601
Synchronous BUCK Regulator in a step down, inductor-based DC/DC converter
application. It also describes the capability of the MCP1601 Evaluation Board and how
to select the desired Synchronous Converter operating mode and program the output
voltage.

The Evaluation Board Schematic is shown is Figure 1-1.

Input

TP1

+V

IN

C1

2

10 µF

1

TP3

Pgnd

TP5

/SHDN

U3

1

1

2

2 pos Switch

ON

ON

1.0 MΩ

2 3

User Guide

Output

TP2

U1

1

2

3

4 5

AGND

4

2

2

R6

R5

1.0 MΩ

1

1

AGNDAGND AGNDAGND

V

IN

SHDN

FB

AGND

MCP1601

TP6

TP7

LX

PGND

V

OUT

SYNC/

PWM

SYNC/PW M

AGND

L1

8

10 µH

7

6

2

C3

47 pF

1

R1

2 1

1.24 MΩ

R2

2 1

634 KΩ

2

R3

619 KΩ

1

U2

1

1ON

2 3

2ON

2 pos Switch

2

R4

200 KΩ

1

4

+V

OUT

2

C2

10 µF

1

TP4

P

GND

FIGURE 1-1: MCP1601 Evaluation Board Schematic.

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2003 Microchip Technology Inc. DS51315A-page 3

MCP1601 Eval. Board User Guide

1.2 DETAILED DESCRIPTION

The MCP1601 is a 500 mA Synchronous BUCK Regulator. Both the high-side BUCK
P-Channel and the low-side N-Channel switches are integrated within the device. The
integrated synchronous switch makes the MCP1601 very efficient, even when convert­ing unregulated input voltages to low voltage fixed outputs. This evaluation board is
designed for a wide range of output voltages and currents. For specific applications,
smaller inductors, shielded inductors, tantalum capacitors and different output voltage
settings can improve the total DC/DC converter performance and cost.

The MCP1601 device can operate in three different modes of operation to optimize the
efficiency of the voltage conversion. The three operating modes are:

• Automatic switching from PFM Mode to PWM mode and back

• Synchronization to external Oscillator

• Fixed Frequency Forced PWM Mode

The MCP1601 output voltage is adjustable and is set by two external divider resistors.
A two-position switch is used on the MCP1601 Evaluation Board to change the resis­tance of the external divider and adjust the output voltage to four different settings.
These output voltage settings are: 1.8V, 2.05V, 2.45V and 3.28V.

1.2.1

Applying Power to the Board

Two surface mount test points are used to apply power to the MCP1601 Evaluation
Board. For proper operation, the input voltage range is 2.7V < +V

< +5.5V for all oper-

IN

ating conditions. The MCP1601 has an internal Under-Voltage Lockout (UVLO) which
will prevent the board from operating when the input voltage is below the specified 2.7V
minimum.

1. Connect the positive side of the external power supply (+) to the +V

2. Connect the negative side (GND) of the external power supply to the P
point which is located directly below the +V

1.2.2

Connecting a Load to the Board

To connect an external load to the board, the +V

• Connect the positive side of the load to the +V

side of the load to the P

test point located directly under the +V

GND

test point.

IN

and P

OUT

pin and the negative or ground

OUT

test points are used.

GND

test point.

IN

test point.

OUT

GND

test

The MCP1601 output is rated for 500 mA (maximum) continuous current. The out­put is protected against over current and short circuit conditions.

1.2.3

Enabling the MCP1601 - Using Switch U3, Position 1

Switch U3, position 1 is used to determine the SHDN mode for the MCP1601 device.
With switch U
of the MCP1601 device is enabled. When switch U
MCP1601 device is in a low quiescent current SHDN

, position 1 pushed to the right, the SHDN pin is pulled up and the output

3

, position 1 is to the left, the

3

mode and the output is disabled.

DS51315A-page 4

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2003 Microchip Technology Inc.

MCP1601 Evaluation Board

1.2.4

Selecting the Operating Mode - Using Switch U3, Position 2

The multi-function SYNC/PWM pin on the MCP1601 is used to set the operating mode
of the device. The three operating modes are:

• Automatic switching from PFM Mode to PWM mode and back

• Synchronization to external Oscillator

• Fixed Frequency Forced PWM Mode

To select automatic PFM/PWM mode:

• Slide switch U

, position 2 to the left or off position. While operating in this mode,

3

the MCP1601 device will automatically select the most efficient operating mode
by approximating the load current internally.

To synchronize the MCP1601 switching frequency to an external oscillator:

• Slide switch U

SYNC/PWM test point located directly below switch U

, position 2 to the left. Connect the external oscillator to the

3

and the A

3

test point.

GND

See the MCP1601 datasheet (DS21762) for external clock specifications. When
synchronizing to an external oscillator, the MCP1601 will operate in the fixed
frequency mode at the same frequency as the external oscillator.

To select fixed frequency mode that operates off of the 750 kHz internal oscillator:

• Slide switch U

, position 2 to the right or “on” position. This will tie the SYNC/PWM

3

pin high and force PWM operation from the internal oscillator, making the
MCP1601 device independent of external load conditions.

1.2.5

Selecting the MCP1601 output voltage

Switch U2 is used to select the output voltage. Refer to Table 1-1 to choose one of the
pre-selected output voltages.

TABLE 1-1: SWITCH SETTINGS FOR PRE-SELECTED OUTPUT

VOLTAGES

U2, Position 1 U2, Position 2

OFF OFF 3.28V

OFF ON 2.45V

ON OFF 2.05V

ON ON 1.8

V

OUT

The output voltage for the MCP1601 device is determined by using the following for­mula.

EQUATION

R

2

1

-------+
R

4

Where: V

V

= 0.8V Typical

REF

R

= 200 kΩ for the Evaluation board

4

is set by the parallel combination of R1, R2 and R3.

R

2

OUT

=



V

REF



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2003 Microchip Technology Inc. DS51315A-page 5

MCP1601 Eval. Board User Guide

1.3 TEST POINTS

1.3.1

/SHDN

The /SHDN or shutdown test point can be used to monitor the level of the shutdown pin
or as an input to the shutdown pin of the MCP1601 device. With switch U

, position 1

3

in the “off” position, a 1 MΩ resistor will pull the pin low.

1.3.2

SYNC/PWM

The SYNC/PWM pin can be used to monitor the level of the SYNC/PWM pin or as an
input to the MCP1601 device. With switch U

, position 2 in the “off” position, a 1 MΩ

3

resistor will pull the pin low.

To synchronize to an external oscillator:

• With switch U

, position 2 in the off position, connect the external oscillator to the

3

SYNC/PWM test point.

1.3.3

The analog ground or A

A

GND

can be used as a quiet ground connection. When using the

GND

external oscillator synchronization function, connect the return or ground of the external
oscillator to the A

test point.

GND

DS51315A-page 6

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2003 Microchip Technology Inc.

MCP1601 Eval. Board

M

Appendix A. Schematic and Board Layouts

A.1 INTRODUCTION

This appendix contains the schematic and board layout diagrams for the MCP1601
Evaluation Board.

A.1.1 Highlights

The MCP1601 Evaluation Board is constructed using one (1) silk screen layer and two
(2) 1 oz. metal wiring layers. The bottom metal wiring layer is a single ground plane
which is routed to partition the P
return pin on the MCP1601 device.

Diagrams included in this appendix:

• Evaluation Board Schematic

• Evaluation Board - Top Silk Screen Layer

• Evaluation Board - Top Metal Layer

• Evaluation Board - Bottom Metal Layer

User Guide

high current return pin from the small signal A

GND

GND

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2003 Microchip Technology Inc. DS51315A-page 7

MCP1601 Eval. Board User Guide

A.2 EVALUATION BOARD SCHEMATIC

Input

TP1

C1

10 µF

TP3

Pgnd

+V

IN

2

1

TP5

/SHDN

U3

1

1

2 3

2

2 pos Switch

ON

ON

1.0 MΩ

4

AGND

2

R5

R6

1.0 MΩ

1

U1

1

V

IN

2

SHDN

3

FB

4 5

AGND

MCP1601

TP6

TP7

2

1

AGNDAGND AGNDAGND

LX

PGND

V

OUT

SYNC/

PWM

SYNC/PW M

AGND

8

7

6

L1

10 µH

C3

47 pF

2

1

A.3 EVALUATION BOARD - SILK SCREEN LAYER

R1

2 1

1.24 MΩ

R2

2 1

634 KΩ

2

R3

619 KΩ

1

U2

1

1ON

2 3

2ON

2 pos Switch

2

R4

200 KΩ

1

Output

TP2

+V

OUT

2

C2

10 µF

1

TP4

P

GND

4

DS51315A-page 8



2003 Microchip Technology Inc.

MCP1601 Evaluation Board

A.4 EVALUATION BOARD - TOP METAL LAYER

A.5 EVALUATION BOARD - BOTTOM METAL LAYER



2003 Microchip Technology Inc. DS51315A-page 9

MCP1601 Eval. Board User Guide

NOTES:

DS51315A-page 10



2003 Microchip Technology Inc.

MCP1601 Eval. Board

M

Appendix B. Bill Of Materials (BOM)

TABLE B-1: BILL OF MATERIALS (BOM)

Reference

Designator

R

1

R

2

R

3

R

4

R

5,R6

C

, C

1

2

C

3

L

1

U

1

U

, U

2

3

TP

- TP

1

7

Qty Description Manufacturer

1

Resistor 1.24 M

1

Resistor 634 k

1

Resistor 619 k

1

Resistor 200 k

2

Resistor 1.00 M

2 Capacitor 10 µF, 6.3V Ceramic X5R 1206 SMD

1 Capacitor 47 pF, 50V Ceramic 0805 SMD

1 10 µH Coilcraft Wafer Inductor

1 Microchip Synchronous BUCK Regulator Microchip

2 DIP Switches, 2-Position, SPST

7 Test Points

4 Bumpons - Protective Products

1/8W 1% 0805 SMD

Ω

1/10W 1% 0805 SMD

Ω

1/10W 1% 0805 SMD

Ω

1/10W 1% 0805 SMD

Ω

1/10W 1% 0805 SMD

Ω

User Guide

®

Yageo

®

Panasonic

ECG

Panasonic

ECG

Panasonic

ECG

Panasonic

ECG

Kemet

Panasonic

ECG

Coilcraft

Technology Inc.

C&K

Keystone

3M

-

®

-

®

-

®

-

®

®

-

®

®

®

®

Manufacturer

Part Number

9C08052A1224FKHFT

ERJ-6ENF6343V

ERJ-6ENF6193V

ERJ-6ENF200V

ERJ-6ENF1004V

C1206C106K9PACT

ECJ-2VC1H470J

LPO2506IB-103

MCP1601

TDA02H0SK1

5016

SJ5003-0



2003 Microchip Technology Inc. DS51315A-page 11

M

W

ORLDWIDE SALES AND SERVICE

AMERICAS

Corporate Office

2355 West Chandler B lvd.
Chandler, AZ 85224-6199
Tel: [phone] Fax: [phone]
Technical Support: 480-792-7627
Web Address: http://www.microchip.com

Rocky Mountain

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Tel: [phone] Fax: [phone]

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Toro nto

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ASIA/PACIFIC

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Tel: [phone] Fax: [phone]

China - Shanghai

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Ta iw an

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EUROPE

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Germany

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Italy

Microchip Technology SRL
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United Kingdom

Microchip Ltd.
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Tel: [phone] Fax: [phone]

12/05/02

DS51315A-page 12  2003 Microchip Technology Inc.