Microchip Technology MCP651 User Manual
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Microchip Technology MCP651 User Manual

Microchip Technology MCP651 User Manual

Input offset
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MCP651
Input Offset

Evaluation Board

User's Guide
© 2009 Microchip Technology Inc.
DS51834A

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Summary of Contents for Microchip Technology MCP651

  • Page 1: Evaluation Board

    MCP651 Input Offset Evaluation Board User’s Guide © 2009 Microchip Technology Inc. DS51834A...
  • Page 2 Mode, Total Endurance, TSHARC, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. 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.

  • Page 3: Table Of Contents

    2.6 Settling Time, Noise and Sampling Rate ............17 Chapter 3. Possible Modifications 3.1 Introduction ....................19 3.2 Range of Parts Supported by MCP651 Input Offset Evaluation Board ..19 3.3 Changes to Accommodate Other DUTs ............21 Appendix A. Schematics and Layouts A.1 Introduction ....................
  • Page 4 MCP651 Input Offset Evaluation Board User’s Guide Appendix B. Bill Of Materials (BOM) B.1 MCP651 Input Offset Evaluation Board BOM ..........31 B.2 Adaptor Board BOM ..................33 Worldwide Sales and Service ..................34 © 2009 Microchip Technology Inc. DS51834A-page iv...

  • Page 5: Preface

    • Customer Support • Document Revision History DOCUMENT LAYOUT This document describes how to use the MCP651 Input Offset Evaluation Board. The manual layout is as follows: • Chapter 1. “Product Overview” - Important information about the MCP651 Input Offset Evaluation Board.

  • Page 6: Conventions Used In This Guide

    MCP651 Input Offset Evaluation Board 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...

  • Page 7: Recommended Reading

    Preface RECOMMENDED READING This user's guide describes how to use MCP651 Input Offset Evaluation Board. Other useful documents are listed below. The following Microchip documents are available and recommended as supplemental reference resources. MCP6V01/2/3 Data Sheet, “300 µA, Auto-Zeroed Op Amps”, DS22058 Gives detailed information on the op amp family that is used for signal processing and output voltage control on the MCP651 Input Offset Evaluation Board.

  • Page 8: Document Revision History

    MCP651 Input Offset Evaluation Board User’s Guide DOCUMENT REVISION HISTORY Revision A (May 2009) • Initial Release of this Document. © 2009 Microchip Technology Inc. DS51834A-page 4...

  • Page 9: Chapter 1. Product Overview

    EVALUATION BOARD USER’S GUIDE Chapter 1. Product Overview INTRODUCTION The MCP651 Input Offset Evaluation Board is described by the following: • Assembly # : 102-00258-R2 • Order # : MCP651EV-VOS • Name: MCP651 Input Offset Evaluation Board Items discussed in this chapter include: •...

  • Page 10: Intended Use

    The MCP651 data sheet describes all of its bias voltages relative to V , which is assumed to be at ground (0V). On the other hand, the MCP651 Input Offset Evaluation Board sets the DUT’s input common mode voltage to 0V. The user needs to convert...
  • Page 11 R28, C12 “Lowpass Filter (ω = 1 / (R28 · C12) Note 1: Switch S2’s top position is closed when to the right (LOW GAIN), and is open when to the left (HI GAIN). © 2009 Microchip Technology Inc. DS51834A-page 7...
  • Page 12 The measured noise, over a 140 second period of time with a typical part, was about 19 µV referred to input (RTI). This compares favorably with the MCP651’s calibrated specification (±200 µV, maximum at +25°C). © 2009 Microchip Technology Inc.
  • Page 13 , along with the capacitors C and C , minimize crosstalk from the other op amps on the board. Since the MCP651’s quiescent current is between 3 mA and 9 mA, the actual power supply voltages (V and V ) are different by 30 mV to 90 mV.
  • Page 14 The DUT’s CAL/CS input pin is normally held at V by resistors R and R ; this keeps the MCP651 in its normal mode of operation. When S is closed by the user, R pulls CAL/CS up to V (after a time set by R...

  • Page 15: Chapter 2. Installation And Operation

    EVALUATION BOARD USER’S GUIDE Chapter 2. Installation and Operation INTRODUCTION This chapter shows how to set up and operate the MCP651 Input Offset Evaluation Board. Items discussed in this chapter include: • Required Tools • Configuring the Lab Equipment and PCB •...

  • Page 16: Configuring The Lab Equipment And Pcb

    Lab equipment is connected to this board as shown in Figure 2-1. The (surface mount) test points allow lab equipment to be connected to these boards. FIGURE 2-1: Lab Equipment Connections and Configuration Switches for the MCP651 Input Offset Evaluation Board. The arrows and numbers in Figure 2-1 signify the following: 1.
  • Page 17 For the best accuracy and ease of use, short VCALX to GND, set the other voltages for the desired bias during calibration, then initiate a calibration event in the DUT (push S1). Change the bias point afterwards to see how is changed. © 2009 Microchip Technology Inc. DS51834A-page 13...

  • Page 18: Operating Conditions

    CAL switch is activated). Normally, the part is on. These numbers are for the MCP651 op amp. Once the MCP651 Input Offset Evaluation Board is powered up, the switches can be set for the desired operation. S1 (a normally off push-button switch) starts a calibration event (CAL), internal to the DUT, when pushed.

  • Page 19: Converting To Other Parameters

    COMMON MODE CHANGE EXAMPLE Given: = 0.5 mV, = 0V = 1.0 mV, = 5V Then: ΔV = 0.5 mV ΔV = 5.0V CMRR = 5.0V / 0.5 mV = 10 V/mV = 80 dB © 2009 Microchip Technology Inc. DS51834A-page 15...
  • Page 20 MCP651 Input Offset Evaluation Board User’s Guide 2.5.2 Application Table 2-3 shows one possible measurement matrix that will allow the user to estimate key parameters for the DUT. Obviously, other values of V and V could be selected. TABLE 2-3:...

  • Page 21: Settling Time, Noise And Sampling Rate

    DUT’s bias point has been changed) to about 0.6 seconds. The noise seen in the measurements is a result of DUT’s input noise voltage passed through the same 1.6 Hz lowpass filter. The MCP651’s 1/f noise dominates at such low frequencies, so V will appear to wander over time.
  • Page 22 MCP651 Input Offset Evaluation Board User’s Guide NOTES: © 2009 Microchip Technology Inc. DS51834A-page 18...

  • Page 23: Chapter 3. Possible Modifications

    USER’S GUIDE Chapter 3. Possible Modifications INTRODUCTION This chapter shows how to modify the MCP651 Input Offset Evaluation Board to measure other single op amps from Microchip Technology Inc. Items discussed in this chapter include: • Range of Parts Supported by the MCP651 Input Offset Evaluation Board •...
  • Page 24 MCP651 Input Offset Evaluation Board User’s Guide 3.2.2 Output Headroom The DUT’s output headroom needs to be close enough to 0V to not overdrive U2 or U3. The maximum DUT V and V values supported (relative to V ) are: EQUATION 3-2: ≤...

  • Page 25: Changes To Accommodate Other Duts

    Parts information can be found in Appendix B. “Bill Of Materials (BOM)”. 3.3.1 Pinout Figure 3-1 shows the MCP651 op amp’s pinout. This is the standard 8-lead pinout, except for pins 5 and 8 (V and CAL/CS). The MCP651 Input Offset Evaluation Board is designed to take advantage of these input pins, but they are not necessary to this board’s operation.
  • Page 26 With a DIP-8 IC Socket on the evaluation board (see Section 3.3.4 “Single Op Amps in PDIP-8 Package”), it is relatively easy to adapt the MCP651 Input Offset Evaluation Board to many other op amps. An adaptor board is stacked on top using headers that solder to the adaptor board, using PDIP-8 through holes, and are inserted into the DIP-8 socket on the evaluation board.
  • Page 27 Evaluation Board available from Microchip Technology Inc. The two interconnect strips on the bottom are soldered into the through holes for the DIP-8 socket. Figure 3-5 shows this board plugged into the MCP651 Input Offset Evaluation Board. Note 1: Build the adaptor board in the following sequence. Insert the interconnect headers into the DIP-8 socket on the MCP651 Input Offset Evaluation Board.
  • Page 28 MCP651 Input Offset Evaluation Board User’s Guide NOTES: © 2009 Microchip Technology Inc. DS51834A-page 24...

  • Page 29: Appendix A. Schematics And Layouts

    Evaluation Board. SCHEMATIC AND LAYOUTS See A.3 “Board – Schematic” for the circuit diagram. U1 is the DUT (MCP651). U2 buffers the attenuated and filtered control voltage VCOX. U3 is the differential integrator. U4 is the amplifier that gives the final gain to the DUT’s input offset voltage ).

  • Page 30: Board - Schematic

    MCP651 Input Offset Evaluation Board User’s Guide BOARD – SCHEMATIC © 2009 Microchip Technology Inc. DS51834A-page 26...

  • Page 31: Board - Combination Of The Top Silk Screen, Top Solder Mask And Top Metal Layers

    Schematics and Layouts BOARD – COMBINATION OF THE TOP SILK-SCREEN, TOP SOLDER MASK AND TOP METAL LAYERS © 2009 Microchip Technology Inc. DS51834A-page 27...

  • Page 32: Board - Top Silk Screen

    MCP651 Input Offset Evaluation Board User’s Guide BOARD – TOP SILK-SCREEN © 2009 Microchip Technology Inc. DS51834A-page 28...

  • Page 33: Board - Top Solder Mask And Top Metal Layer

    Schematics and Layouts BOARD – TOP SOLDER MASK AND TOP METAL LAYER © 2009 Microchip Technology Inc. DS51834A-page 29...

  • Page 34: Board - Bottom Metal Layer

    MCP651 Input Offset Evaluation Board User’s Guide BOARD – BOTTOM METAL LAYER © 2009 Microchip Technology Inc. DS51834A-page 30...

  • Page 35: B.1 Mcp651 Input Offset Evaluation Board Bom

    USER’S GUIDE Appendix B. Bill Of Materials (BOM) MCP651 INPUT OFFSET EVALUATION BOARD BOM The BOM in Table B-1 shows all of the components assembled on the PCB. Table B-2 shows alternate components that can be placed on this PCB (after modification).
  • Page 36 Unknown Value, 0603 SMD, X7R, 16V, 10% Panasonic -ECG — Note 1: The components listed in this Bill of Materials are representative of the PCB assembly. The released BOM used in manufacturing uses all RoHS-compliant components. © 2009 Microchip Technology Inc. DS51834A-page 32...

  • Page 37: B.2 Adaptor Board Bom

    Single Op Amp in Standard 8-pin pinout Microchip Technology MCP6XXX Inc. Note 1: The components listed in this Bill of Materials are representative of the PCB assembly. The released BOM used in manufacturing uses all RoHS-compliant components. © 2009 Microchip Technology Inc. DS51834A-page 33...
  • Page 38 Thailand - Bangkok Santa Clara, CA Tel: 86-29-8833-7252 Tel: 66-2-694-1351 Tel: 408-961-6444 Fax: 86-29-8833-7256 Fax: 66-2-694-1350 Fax: 408-961-6445 China - Zhuhai Toronto Tel: 86-756-3210040 Mississauga, Ontario, Fax: 86-756-3210049 Canada Tel: 905-673-0699 Fax: 905-673-6509 03/26/09 © 2009 Microchip Technology Inc. DS51834A-page 34...
  • Page 39 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Microchip MCP651EV-VOS...

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