Nellcor N-40 Service manual

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SERVICE MANUAL

NPB-40 Handheld Pulse Oximeter

Caution: Federal law (U.S.) restricts this device to sale by or on the order of a physician. To contact Nellcor Puritan Bennett’s representative: In the United States, call 1-800-635-5267 or

925-463-4000; outside of the United States, call your local Nellcor Puritan Bennett representative.

0123

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Nellcor Puritan Bennett Inc. 4280 Hacienda Drive Pleasanton, CA 94588 USA Telephone Toll Free 1.800.NELLCOR

Tyco Healthcare UK LTD Fareham Road Gosport PO13 0AS U.K. Tel: +44.1329.224000

To obtain information about a warranty, if any, for this product, contact Nellcor

Puritan Bennett Technical Services Department, or your local Nellcor Puritan

Bennett representative. Notice: Purchase of this instrument confers no express or implied license under any

Nellcor Puritan Bennett patent to use the instrument with any sensor that is not manufactured or licensed by Nellcor Puritan Bennett.

Oxisensor II is a trademark of Nellcor Puritan Bennett, Inc. Covered by one or more of the following U.S. Patents and foreign equivalents:

4,621,643; 4,653,498; 4,700,708; 4,770,179; 4,869,254; 4,928,692; 4,934,372; 5,078,136; 5,351,685; 5,368,026; and Re. 35,122.

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TABLE OF CONTENTS

List of Figures List of Tables

Section 1: Introduction................................................................................. 1-1

1.1 Manual Overview............................................................................ 1-1

1.2 Equipment Description ................................ ................................ ... 1-1

Section 2: Routine Maintenance ................................................................ 2-1

2.1 Maintenance Overview ................................................................... 2-1

2.2 Battery Maintenance ...................................................................... 2-1

2.3 Cleaning ................................ ................................ ............................ 2-2

Section 3: Performance Verification .......................................................... 3-1

3.1 Performance Verification ................................................................... 3-1

Section 4: Troubleshooting ................................................................ ......... 4-1

4.1 Introduction..................................................................................... 4-1

4.2 Who Should Perform Repairs......................................................... 4-1

4.3 Repair Level Supported.................................................................. 4-1

4.4 How to Use This Section ................................ ................................ 4-1

4.5 Obtaining Replacement Parts ........................................................ 4-1

4.6 Troubleshooting Guide ................................................................... 4-2

Section 5: Disassembly Guide .................................................................... 5-1

5.1 Introduction..................................................................................... 5-1

5.2 System Disassembly and Reassembly .......................................... 5-1

Section 6: Spare Parts.................................................................................. 6-1

6.1 Introduction..................................................................................... 6-1

Section 7: Packing for Shipment................................................................. 7-1

7.1 General Instructions........................................................................ 7-1

7.2 Packing NPB-40 in Original Carton ................................ ................ 7-1

7.3 Packing in a Different Carton ......................................................... 7-1

Section 8: Specifications ................................................................ ............. 8-1

8.1 Performance ................................................................................... 8-1

8.2 Electrical ......................................................................................... 8-2

8.3 Environmental................................................................................. 8-2

8.4 Physical ......................................................................................... 8-3

Technical Supplement.................................................................................. S-1

S1 Introduction..................................................................................... S-1

S2 Pulse Oximetry Principles of Operation .......................................... S-1

S3 Circuit Analysis ............................................................................... S-2

S4 Schematic Diagrams ................................ ................................ ...... S-17

2.2.1 Battery Replacement ......................................................... 2-1

2.2.2 Battery Disposal ................................................................ 2-2

S2.1 Overview ................................................................ ........... S-1

S2.2 Functional Versus Fractional Saturation............................ S-1

S2.3 Measured versus Calculated Saturation............................ S-2

S3.1 Overall Unit Block Diagram Analysis ................................ . S-3

S3.2 CPU PCB Theory of Operation.......................................... S-5

S3.3 LCD PCB Theory of Operation .......................................... S-11

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Table of Contents

LIST OF FIGURES

1-1 NPB-40 Handheld Pulse Oximeter ................................................ 1-1

1-2 NPB-40 Front Panel....................................................................... 1-2

2-1 NPB-40 Battery Installation ........................................................... 2-2

3-1 NPB-40 Self-Test Front Panel Display ................................ .......... 3-1

3-2 Printer Interface Setup................................................................... 3-3

3-3 Typical Average Data Print Out ..................................................... 3-4

3-4 Typical Data Print Out ................................................................... 3-5

4-1 Typical Error Code Display ............................................................ 4-2

5-1 Opening the NPB-40 Case ............................................................ 5-2

5-2 Top Case Removal ........................................................................ 5-2

5-3 Unlocking CPU PCB Connector J3 ............................................... 5-3

5-4 Separating LCD PCB from CPU PCB............................................ 5-3

6-1 NPB-40 Expanded View ................................................................ 6-2

7-1 Repacking the NPB-40 .................................................................. 7-2

S2-1 Oxyhemoglobin Dissociation Curve .............................................. S-2

S3-1 NPB-40 Block Diagram ................................................................. S-4

S3-2 CPU PCB Block Diagram .............................................................. S-6

S3-3 LCD PCB Block Diagram............................................................... S-12

S4-1 CPU PCB Parts Locator Diagram.................................................. FO-1

S4-2 LCD PCB Parts Locator Diagram .................................................. FO-2

S4-3 CPU PCB Schematic Diagram ...................................................... FO-3

S4-4 LCD PCB Schematic Diagram....................................................... FO-4

S4-5 Front Panel Keypad Schematic Diagram ...................................... FO-5

LIST OF TABLES

4-1 Troubleshooting Guide .................................................................. 4-2

4-2 NPB-40 Error Codes ..................................................................... 4-5

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SECTION 1: INTRODUCTION

1.1 Manual Overview

1.2 Equipment Description

1.1 MANUAL OVERVIEW

This manual contains information for servicing the NPB-40 handheld pulse oximeter. Only qualified service personnel should service this product. Before servicing the NPB-40, read the operator’s manual carefully for a thorough understanding of how to operate the NPB-40.

1.2 EQUIPMENT DESCRIPTION

The Nellcor Puritan Bennett NPB-40 handheld pulse oximeter is used for noninvasive spot-check measurement of functional oxygen saturation of arterial hemoglobin (SpO2) and pulse rate (measured by the SpO2 sensor). The NPB-40 is for attended monitoring only, and must be used in the continuous presence of a qualified healthcare provider. The NPB-40 can be used on adult, pediatric, and neonatal patients. It can be used in mobile environments when protected from excessive moisture such as direct rainfall. The NPB-40 is powered by four “AA” cell alkaline batteries. An external Hewlett-Packard HP82240B printer can be used with the NPB-40 to printout readings stored in the NPB-40 memory. This printer is available from Nellcor Puritan Bennett. The NPB-40 handheld pulse oximeter is illustrated in Figure 1-1.

Figure 1-1: NPB-40 Handheld Pulse Oximeter

The NPB-40 is operated using a four-key keypad and an LCD display on the front panel as shown in Figure 1-2. Refer to the NPB-40 operator’s manual for complete operating instructions.

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Section 1: Introduction

12 11

Pulse Amplitude indicator

3 4

Pulse Rate display

Pulse Search display

Low Battery indicator

Sensor disconnect indicator

Power On/Off key

Display Light/Beep On/Off key

Store Data/Print key

Shift key

Store Data icon

Shift icon

Print icon

SpO2% display

Figure 1-2: NPB-40 Front Panel

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SECTION 2: ROUTINE MAINTENANCE

2.1 Maintenance Overview

2.2 Battery Maintenance

2.3 Cleaning

2.1 MAINTENANCE OVERVIEW

The NPB-40 requires no routine service or calibration. The performance verification tests in Section 3, Performance Verification, may be used following repairs or during routine maintenance (if required by your local institution).

2.2 BATTERY MAINTENANCE

Warning: The NPB-40 uses four “AA” cell alkaline batteries for operation. If batteries are not replaced when recommended or are not disposed of properly, serious personal injury or damage to the NPB-40 could result.

Caution: When inserting the positive end of each battery, exercise caution to not damage the small coiled spring contact.

Nellcor Puritan Bennett recommends that you comply with the following guidelines for battery replacement and battery disposal as a minimum.

2.2.1 Battery Replacement

Caution: The NPB-40 could be damaged by batteries that are left unused in the unit and begin to leak. Never store the NPB-40 with the batteries installed for a prolonged period of time.

NPB-40 batteries should be replaced whenever a low battery indication is observed on the unit. Remove the batteries if you will be storing the NPB-40 for longer than one month. Refer Figure 2-1 for replacing the batteries.

Note: For easier battery installation, insert the negative end of the battery

first when installing each battery.

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Section 2: Routine Maintenance

2.2.2 Battery Disposal

2.3 CLEANING

Figure 2-1: NPB-40 Battery Installation

When NPB-40 batteries have been replaced, dispose of the old batteries. Always follow local ordinances when disposing of the NPB-40 batteries.

Warning: Never dispose of NPB-40 batteries by burning. The batteries could explode in fire and cause serious personal injury.

Caution: Do not immerse the NPB-40 or accessories in liquid or use caustic or abrasive cleaners.

To clean the NPB-40, dampen a soft cloth with a commercial nonabrasive cleaner and wipe the unit with the cloth.

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SECTION 3: PERFORMANCE VERIFICATION

3.1 Performance Verification

3.1 PERFORMANCE VERIFICATION

The performance of the NPB-40 can be verified using the following procedure. Before performing this procedure, the NPB-40 must have fresh batteries installed. If any of the required observations cannot be obtained, do not return the NPB-40 to service before referring to Section 4, Troubleshooting.

You will need an SRC-2 pulse oximeter tester to perform this procedure. If the performance of the printing function will be verified, you will need an HP82240B printer.

The NPB-40 is to be turned off and any sensors disconnected before performing this procedure.

1. Press the On/Off key on the front panel keypad.

2. The NPB-40 will perform a self-test. Verify that all display segments are lit during the self-test as shown in Figure 3-1. Also verify that a low pitched audio tone is heard at the end of the self test. Also verify that you then hear a high, a low, and a high pitch error tone indicating that a sensor is not connected. Verify that dashes are shown on the display and the SENSOR DISCONNECT indicator is flashing.

Figure 3-1: NPB-40 Self-Test Front Panel Display

3. Wait for 20 to 40 seconds. Verify that two triple beeps are heard. Verify that the NPB-40 then shuts itself off.

4. Connect an SRC-2 pulse oximeter tester to the NPB-40 sensor connector.

Note: If the SRC-2 is connected directly to the NPB-40 sensor

connector, its controls will be facing the opposite direction of the NPB-40 controls. Connecting the SRC-2 through a sensor extension cable, such as the Nellcor Puritan Bennett model EC4 or EC-8, will make it easier to perform this procedure.

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Section 3: Performance Verification

Set the SRC-2 controls as follows:

RATE 112 LIGHT HIGH 1 MODULATION HIGH LOCAL/REMOTE/RCAL LOCAL

5. Press the On/Off key on the NPB-40 front panel keypad.

6. When the self-test is complete, verify that the PULSE SEARCH indicator illuminates momentarily and verify that the NPB-40 is displaying a pulse rate of 112 (±3 bpm), that the pulse amplitude indicator is displaying properly, that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can be heard, and that the PULSE SEARCH indicator is off.

7. Set the following SRC-2 controls as indicated:

RATE 38 LIGHT HIGH 2 MODULATION LOW

Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of 38 (±3 bpm), that the pulse amplitude indicator is displaying properly, that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can be heard, and that the PULSE SEARCH indicator is off.

8. Set the following SRC-2 controls as indicated:

RATE 201 LIGHT LOW

Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of 201 (±3 bpm), that the pulse amplitude indicator is displaying properly, that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can be heard, and that the PULSE SEARCH indicator is off.

9. Set the following SRC-2 control as indicated: MODULATION HIGH Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of

201 (±3 bpm), that the pulse amplitude indicator is displaying properly, that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can be heard, and that the PULSE SEARCH indicator is off.

10. Press the Shift key followed by the Display Light/Beep On/Off key. Verify that the SHIFT indicator illuminates when the Shift key is pressed then verify that the pulse beep stops and the SHIFT indicator extinguishes when the Display Light/Beep On/Off key is pressed.

11. Press the Shift key followed by the Display Light/Beep On/Off key and verify that the pulse beep can be heard again at a low level.

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Section 3: Performance Verification

12. Press the Shift key followed by the Display Light/Beep On/Off key and verify that the pulse beep can again be heard again at a higher level.

13. Press and release the Display Light/Beep On/Off key on the front panel keypad and verify that the LCD backlight comes on, remains on and the LCD is adequately illuminated.

14. Press the Display Light/Beep On/Off key on the front panel keypad and verify that the LCD backlight is off.

15. Set the following SRC-2 control as indicated: LOCAL/REMOTE/RCAL REMOTE

16. On the NPB-40, verify that the PULSE SEARCH indicator illuminates after a few seconds and that the number “0” is displayed in the SpO2% and pulse rate displays.

17. Set the following SRC-2 control as indicated: LOCAL/REMOTE/RCAL LOCAL

18. On the NPB-40, verify that the PULSE SEARCH indicator illuminates momentarily and verify that the NPB-40 is displaying a pulse rate of 201 (±3 bpm), that the pulse amplitude indicator is displaying properly, that the SpO2% indicator is displaying 79 to 83, that a pulse beep can be heard, and that the PULSE SEARCH indicator is off.

Note: If an HP82240B printer is not available, skip steps 19 through

27 and proceed to step 28.

19. Refer to the printer operator’s manual as needed. Verify that paper is properly installed in the printer and turn the printer on.

20. Align the NPB-40 with the printer as shown in Figure 3-2.

0°–5°

1"–2" (2.5–5.1 cm.)

Figure 3-2: Printer Interface Setup

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Section 3: Performance Verification

21. On the NPB-40, press the Shift key followed by the Store Data/Print key on the front panel keypad.

Note: In the following steps, printed SpO2% values will be 79 to 83

22. Verify that the PRINT icon is illuminated on the NPB-40 display, that the printer begins printing and that the printer prints out a summary report similar to that shown in Figure 3-3.

and pulse rate values will be 201, ±3 bpm. Figures 3-3 and 3-4 are examples of typical print outs. The NPB-40 will not display pulse or SpO2% values while printing.

Figure 3-3: Typical Average Data Print Out

23. With the SRC-2 connected to the NPB-40 and still set up as in step 18, press only the Store Data/Print key on the front panel keypad and verify that the LCD display indicates “1-Id” and the STORE DATA icon illuminates.

24. Press only the Store Data/Print key on the front panel keypad and verify that the LCD display indicates “2-Id” and the STORE DATA icon illuminates.

25. Press only the Store Data/Print key on the front panel keypad and verify that the LCD display indicates “3-Id” and the STORE DATA icon illuminates.

26. Align the NPB-40 with the printer as shown in Figure 3-2 and press the Shift key on the NPB-40 front panel keypad, followed by the Store Data/Print key.

27. Verify that the PRINT icon is illuminated on the NPB-40 display, that the printer begins printing and that the printer prints out data similar to that shown in Figure 3-4. As data stored in steps 24, 25, and 26 is printed out, the NPB-40 display will indicate “1-Id”, “2-Id”, and “3-Id”, respectively.

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Section 3: Performance Verification

Figure 3-4: Typical Data Print Out

28. Press the On/Off key on the front panel keypad.

29. Verify that the NPB-40 shuts off.

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SECTION 4: TROUBLESHOOTING

4.1 Introduction

4.2 Who Should Perform Repairs

4.3 Repair Level Supported

4.4 How to Use This Section

4.5 Obtaining Replacement Parts

4.6 Troubleshooting Guide

4.1 INTRODUCTION

This section provides information for troubleshooting the NPB-40 and helping you to isolate a failure to the front panel keypad, the CPU PCB, or the LCD PCB. A troubleshooting guide is provided in Paragraph 4.6, “Troubleshooting Guide” that lists possible difficulties, along with probable causes, and recommended actions to correct each difficulty. The Technical Supplement at the end of this manual provides information on how the components of the NPB-40 function.

4.2 WHO SHOULD PERFORM REPAIRS

Only qualified service personnel should remove and replace components of the NPB-40. Repairs to the NPB-40 are limited to the repair level identified in Paragraph 4.3, “Repair Level Supported.” If your facility does not have qualified service personnel, contact the Nellcor Puritan Bennett Technical Services Department or your local Nellcor Puritan Bennett representative.

4.3 REPAIR LEVEL SUPPORTED

Besides the batteries, the NPB-40 has five replaceable components, the case top with the front panel keypad, the case bottom, the CPU PCB, the LCD PCB, and the battery compartment door.

4.4 HOW TO USE THIS SECTION

Failures of the case bottom, the battery compartment door, and the case top, not including the front panel keypad, are determined by visually inspecting these components for cracks or deformations and for mechanical failures such as the screw holes stripping out in the case top. The case top and the front panel keypad are replaced together. Use the troubleshooting guide provided in Paragraph 4.6, “Troubleshooting Guide” to isolate failure to the front panel keypad, the CPU PCB, or the LCD PCB. Once a failure has been isolated, refer to Section 5, Disassembly Guide for instructions for removing and replacing a component of the NPB-40.

4.5 OBTAINING REPLACEMENT PARTS

Nellcor Puritan Bennett Technical Services Department provides technical assistance information and replacement parts. To obtain replacement parts, contact the Nellcor Puritan Bennett Technical Services Department or your local Nellcor Puritan Bennett representative. Refer to parts by the part names and part numbers listed in Section 6, Spare Parts.

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Section 4: Troubleshooting

4.6 TROUBLESHOOTING GUIDE

If you encounter a problem that cannot be resolved through a visual inspection, refer to Table 4-1 which provides a list of symptoms, probable causes, and recommended actions to take to correct the problem. It is recommended that corrective actions be performed in the order presented. For a symptom that is not listed in Table 4-1, contact the Nellcor Puritan Bennett Technical Services Department or your local Nellcor Puritan Bennett representative.

If an error code is shown on the front panel LCD display, as shown in Figure 4-1, turn the NPB-40 off and back on again. If the error code still persists, refer to Table 4-2 for the indicated failure and corrective action.

Figure 4-1: Typical Error Code Display

Once you have performed the recommended action, reassemble the NPB-40, refer to Section 3, Performance Verification, and conduct a performance verification before returning the NPB-40 to service. If the symptom persists, continue troubleshooting.

Table 4-1: Troubleshooting Guide

Symptom Probable Cause Corrective Action

The unit does not turn on when the On/Off key is

The batteries are missing.

Open the battery compartment and if batteries are missing, install new batteries.

pressed.

The batteries are installed incorrectly or are backwards.

Open the battery compartment and if batteries are not installed correctly, remove and reinstall the batteries.

The batteries are at

Install new batteries.

or near a voltage too (Continued on next page)

low for the NPB-40 to

operate.

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Section 4: Troubleshooting

Table 4-1: Troubleshooting Guide (Continued)

Symptom Probable Cause Corrective Action

The unit does not turn on when the

The sensor is

defective.

Replace the sensor.

On/Off key is pressed. (continued)

The front panel

keypad is defective.

Open the NPB-40, disconnect the case top from J3 on the CPU PCB and connect an ohmmeter between the flex circuit conductor for J3, pin 5 and the conductor for J3, pin 3. Observe a short when the On/Off key is pressed and an open when not pressed. If incorrect, replace case top. If all keys function correctly, replace CPU PCB.

Caution: Unlock J3 before attempting to remove flex circuit conductor.

Flex circuit between

front panel and CPU

PCB is disconnected.

A CPU PCB

component has

failed.

Inspect the flex circuit between the front panel and the CPU PCB and reconnect if loose.

Inspect the CPU PCB components and circuit board for cracking, burning, or damage, and replace the CPU PCB if any are found. If any failed components are observed, replace CPU PCB.

Replace the CPU PCB with a known good PCB.

One or more keys on the front panel keypad does not work.

The front panel

keypad is defective.

Open the NPB-40, disconnect the case top from J3 on the CPU PCB and connect an ohmmeter lead to the flex circuit conductor for J3, pin 3. Refer to the front panel schematic diagram and individually connect the other ohmmeter lead to each conductor for the other keys. Observe a short when the key is pressed and an open when not pressed. If incorrect, replace case top. If correct, replace the CPU PCB.

Caution: Unlock J3 before attempting to remove flex circuit conductor.

Flex circuit between

front panel and CPU

PCB is disconnected.

A CPU PCB

component has

failed. (Continued on next page)

Inspect the flex circuit between the front panel and the CPU PCB and reconnect if loose.

Inspect the CPU PCB components and circuit board for cracking, burning, or damage and replace the CPU PCB if any are found.

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Section 4: Troubleshooting

One or more keys on the front panel keypad does not work. (Continued)

One or more display segments does not work.

Beeper does not beep for pulse indication or no sound can be heard from the beeper.

Pulse rate or SpO2 value is not displayed and the unit is on.

LCD backlight does not come on when the Display Light key is pressed.

The unit shuts off when the LCD backlight is turned on.

Table 4-1: Troubleshooting Guide (Continued)

Symptom Probable Cause Corrective Action

CPU PCB has failed. Replace the CPU PCB with a

known good PCB.

An LCD PCB

component has

failed.

Inspect the LCD PCB components and circuit board for cracking, burning, or damage and replace the LCD PCB if any are found.

Flex circuit between

LCD and LCD PCB

has come loose.

Inspect the flex circuit between the LCD and the LCD PCB has come loose and replace the LCD PCB if loose.

Replace the LCD PCB with a known good PCB.

The beeper has been

Turn the beeper back on. turned off or its volume is turned down too low to hear.

The holes for the beeper on the back of

Clear the holes for the beeper on

the back of the NPB-40. the NPB-40 are blocked.

The external output port on the CPU PCB

Replace the CPU PCB with a

known good PCB. has failed.

The beeper on the LCD PCB has failed

The SpO2 sensor is not connected

Replace the LCD PCB with a

known good PCB.

Connect the SpO2 sensor to the

NPB-40. properly.

The SpO2 sensor has failed.

A component on the LCD PCB has failed.

A component on the CPU PCB has failed.

The Display Light key on the front panel keypad is

Replace the SpO2 sensor with a

known good SpO2 sensor.

Replace the LCD PCB with a

known good PCB.

Replace the CPU PCB with a

known good PCB.

See “One or more keys on the

front panel keypad does not

work,” above. defective.

The backlight LEDs on the LCD PCB

Replace the LCD PCB with a

known good PCB. have failed.

The batteries are at

Install new batteries. or near a voltage too low for the NPB-40 to operate.

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Section 4: Troubleshooting

Table 4-1: Troubleshooting Guide (Continued)

Symptom Probable Cause Corrective Action

Printer will not print.

The printer is turned off.

The Store Data key on the front panel keypad is defective.

Turn on the printer.

See One or more keys on the

front panel keypad does not

work, above.

The printer batteries are at or near a

Install new batteries in the

printer. voltage too low for it to operate.

The NPB-40 and printer are not properly aligned.

A component on the LCD PCB has failed.

A component on the CPU PCB has failed.

The printer is defective.

Refer to the operator’s manual

for instructions for aligning the

NPB-40 with the printer.

Replace the LCD PCB with a

known good PCB.

Replace the CPU PCB with a

known good PCB.

Attempt to print using another

known good NPB-40. If the

printer still does not print,

troubleshoot the printer

Table 4-2: NPB-40 Error Codes

Error Code Failure Indicated Corrective Action

100EEE Failure in the

1. Replace the sensor. microprocessor analog-to-digital converter on the CPU

2. Replace the CPU PCB with a

known good PCB.

PCB.

150EEE Failure of the

microprocessor on

Replace the CPU PCB with a known good PCB.

the CPU PCB.

151EEE Failure of the RAM

on the CPU PCB.

152EEE Failure of the ROM

on the CPU PCB.

153EEE Failure in the

microprocessor I/O

Replace the CPU PCB with a known good PCB.

Replace the CPU PCB with a

known good PCB. ports on the CPU PCB.

154EEE Failure of the

watchdog circuit on

Replace the CPU PCB with a

known good PCB. the CPU PCB.

155EEE Failure of the

memory on the CPU

Replace the CPU PCB with a

known good PCB. PCB when storing an event or when printing.

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SECTION 5: DISASSEMBLY GUIDE

5.1 Introduction

5.2 System Disassembly and Reassembly

5.1 INTRODUCTION

The NPB-40 can be disassembled into five assemblies:

• Case top/front panel keypad

• Case bottom

• CPU PCB

• LCD PCB

• Battery compartment door Note: Some spare parts you receive will have a business reply card

attached. When you receive these spare parts, please fill out and return the business reply card.

The only tool you will need to disassemble or reassemble the NPB-40 is a Number 1 (medium) Phillips-head screwdriver.

Caution: Observe ESD (electrostatic discharge) precautions when disassembling and reassembling the NPB-40 and when handling any of the components of the NPB-40.

5.2 SYSTEM DISASSEMBLY AND REASSEMBLY

Use the following procedure to disassemble the NPB-40. Reassemble the monitor in reverse order and, if the unit is to be returned to service, install batteries when reassembly is complete and replace the battery compartment door. Nellcor Puritan Bennett recommends that you follow this disassembly procedure in the order presented.

Note: Before you begin to disassemble the NPB-40, remove the battery

compartment door and remove the batteries.

1. Place the NPB-40 on a nonabrasive surface so that the back of the unit is up and the bottom of the unit is closest to you.

2. Remove the four screws holding the case together as indicated in Figure 5-1.

Note: The two screws at the top of the NPB-40 are longer than those

at the bottom. When reassembling the unit, be sure to install the longer screws at the top and the shorter screws at the bottom.

Caution: When reassembling the NPB-40, hand tighten the screws that hold the NPB-40 case together to a maximum of 4 inch-pounds. Over tightening could cause the screws to strip out the screw-holes in the top case, rendering it unusable.

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Section 5: Disassembly Guide

Remove screws

Figure 5-1: Opening the NPB-40 Case

3. While holding the case together, turn the NPB-40 over with the front panel up and the bottom of the unit closest to you.

4. Separate the case top from the bottom case on the right side of the unit and rotate the case top to the left as shown in Figure 5-2.

5-2

Figure 5-2: Top Case Removal

Page 23

Section 5: Disassembly Guide

Caution: Failure to unlock connector J3 on the CPU PCB before attempting to remove the front panel flex circuit could damage the flex circuit.

5. Unlock connector J3 on the CPU PCB as shown in Figure 5-3 and pull the front panel keypad flex circuit out of J3.

Note: When reassembling the NPB-40, be sure to lock J3 after you

insert the front panel keypad flex circuit. See Figure 5-3.

Unlock

J3 Lock

Lock

CPU PCB

Figure 5-3: Unlocking CPU PCB Connector J3

Note: The battery connectors (spring assemblies) at the bottom of the

CPU PCB are held in slots in the battery compartment. In the next step, observe how these connectors are engaged in these slots when you remove the CPU PCB with the LCD PCB and make sure the battery connectors are inserted back in these slots when you reassemble the NPB-40.

6. Lift the CPU PCB and the LCD PCB together and remove them from the case bottom.

7. To separate the CPU PCB and the LCD PCB, grasp the CPU PCB in one hand and the LCD PCB in the other. Rotate the ends of the two PCBs as shown in figure 5-4 until the two assemblies separate at the connectors J1 and J2.

LCD PCB

CPU PCB

Figure 5-4: Separating LCD PCB from CPU PCB

Note: When reassembling the NPB-40, be sure to align all 20 pins of

both J1 and J2 on the CPU PCB with all 20 sockets of J1 and J2 on the LCD PCB before pressing the two PCBs together.

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SECTION 6: SPARE PARTS

6.1 Introduction

6.1 INTRODUCTION

Spare parts, along with corresponding Nellcor Puritan Bennett part numbers, are shown below. Figure 6-1 shows the replaceable NPB-40 monitor components with numbered callouts that correspond to item numbers in parentheses in the spare parts list below.

In December, 1997, the external plastic parts of the NPB-40 were modified. Plastic parts made after that date are incompatible with parts made before that time.

To determine which part number to order, look at the back of the instrument. To the right of center, just above the battery compartment door, there will be either 3 holes or three slots for the speaker. If your instrument has three slots, use part numbers from the “After 12/97” column. If the instrument has three holes, use part numbers from the “Before 12/97” column.

Item Part Numbers

(Before 12/97)

(1) Case Top/Keypad 045691 048863 (2) CPU PCB 034311 034311 (3) LCD PCB 034835 034835 (4) Case Bottom 035097 035397 (5) Battery Compartment Door 033880 034975

Part Numbers

(After 12/97)

6-1

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Section 6: Spare Parts

Figure 6-1: NPB-40 Expanded View

6-2

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SECTION 7: PACKING FOR SHIPMENT

7.1 General Instructions

7.2 Packing NPB-40 in Original Carton

7.3 Packing in a Different Carton

7.1 GENERAL INSTRUCTIONS

To ship an NPB-40 handheld pulse oximeter or one of its components for any reason, follow the instructions in this section.

Pack the NPB-40 or component carefully. Failure to follow the instructions in this section may result in loss or damage not covered by any applicable Nellcor Puritan Bennett warranty. If available, use the original carton and packing materials and follow the instructions in “Packing in Original Carton.” If the original shipping carton and material are not available, use other suitable shipping materials and container and follow the instructions in “Packing in a Different Carton.”

Prior to shipping the NPB-40 or component, contact Nellcor Puritan Bennett Technical Services Department or your local Nellcor Puritan Bennett representative for a Returned Goods authorization (RGA) number. Mark the shipping carton and any shipping forms with the RGA number.

Caution: Observe ESD (electrostatic discharge) precautions when packing any NPB-40 components.

7.2 PACKING NPB-40 IN ORIGINAL CARTON

If the original carton and packing materials are available, repack the NPB-40 as shown in Figure 7-1. Add packing material in the bottom of the carton as needed so the NPB-40 will not be able to move during shipment.

7.3 PACKING IN A DIFFERENT CARTON

If the original carton and packing material are not available when shipping an NPB-40 or one of its components:

1. Place the NPB-40 or component in a plastic bag.

2. Locate a corrugated cardboard shipping carton with at least 200 pounds per square inch (psi) bursting strength.

3. Fill the bottom of the carton with at least 2 inches of packing material.

4. Place the bagged NPB-40 or component on the layer of packing material and fill the box completely with packing material such that there is at least 2 inches of packing material around all sides of the item.

5. Seal the carton with packing tape.

6. Label carton with shipping address, return address, and RGA number.

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Section 7: Packing for Shipment

7-2

Figure 7-1: Repacking the NPB-40

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SECTION 8: SPECIFICATIONS

8.1 Performance

8.2 Electrical

8.3 Environmental

8.4 Physical

8.1 PERFORMANCE

Measurement Range

SpO2

0–100%

Pulse Rate

20–250 beats per minute (bpm)

Accuracy

SpO2 Adults

70–100% ± 2 digits 0–69% unspecified

Neonates

70–100% ± 2 digits 0–69% unspecified

Note: Accuracies are expressed as plus or minus “X” digits (oxygen

saturation percentage points) between saturations of 70-100%. This variation equals plus or minus one standard deviation (1SD), which encompasses 68% of the population. All accuracy specifications are based on testing the subject monitor on healthy adult volunteers in induced hypoxia studies across the specified range. Adult accuracy is determined with Oxisensor® II D-25 sensors. Neonatal accuracy is determined with Oxisensor II N-25 sensors. In addition, the neonatal accuracy specification is adjusted to take into account the theoretical effect of fetal hemoglobin in neonatal blood on oximetry measurements.

Pulse Rate

20–250 bpm ± 3 bpm Note: Accuracy is expressed as plus or minus 3 bpm across the display

range. This variation equals plus or minus one standard deviation (1SD), which encompasses 68% of the population.

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Section 8: Specifications

8.2 ELECTRICAL

Instrument

Power Requirements

6V, supplied by battery-power only

Patient Isolation

No electrical connection to patient (inherently insulated)

Battery

Type

Four 1.5V alkaline “AA” size batteries

Battery Capacity

Typically 19 hours with four new disposable alkaline batteries. Note: Not all brands of off-the-shelf alkaline batteries provide the same

8.3 ENVIRONMENTAL

Operating Temperature

battery life.

Instrument

0 to 55°C

Sensor

Within physiologic range for specified accuracy

Transport/Storage Temperature (boxed)

-40 to 70°C, 15-95% RH

Humidity

Operating

15-95% noncondensing

Storage (unboxed)

15-95% noncondensing over a temperature range of -20° C to 60° C

Altitude

Operating

-1280 ft. to 12,000 ft (-390 m to 3,658 m) [650 to 1060 hPa]

Storage

-2330 ft. to 15,000 ft. (-457 m to 4,573 m) [572 to 1100 hPa]

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8.4 PHYSICAL

Section 8: Specifications

Weight (with batteries installed)

0.3 kg (11 oz.)

Size

15.75 cm high x 7.5 cm wide x 3.8 cm deep

(6.2 in. high x 2.95 in. wide x 1.5 in. deep)

Equipment Classification (IEC 601-1 / CSA 601.1 / UL 2601-1)

Type of Protection

Internally Powered

Degree of Protection

Type BF

Enclosure Degree Protection Class

IPX1

Mode of Operation

Continuous

8-3

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TECHNICAL SUPPLEMENT

S1 Introduction S2 Pulse Oximetry Principles of Operation S3 Circuit Analysis S4 Schematic Diagrams

S1 INTRODUCTION

This Technical Supplement provides a description of the principles of pulse oximetry, a block diagram level theory of operation discussion, and a schematic level theory of operation discussion. Part locator diagrams and schematic diagrams are located at the end of this section as fold-out drawings. These diagrams can be folded out for review while reading the theory of operation.

S2 PULSE OXIMETRY PRINCIPLES OF OPERATION

S2.1 Overview

The NPB-40 is based on the principles of spectrophotometry and optical plethysmography. Optical plethysmography uses light absorption technology to reproduce waveforms produced by pulsatile blood. The changes that occur in the absorption of light due to vascular bed changes are reproduced by the pulse oximeter as plethysmographic wave forms.

Spectrophotometry uses various wavelengths of light to qualitatively measure light absorption through given substances. Many times each second, the NPB-40 passes red and infrared light into the sensor site and determines absorption. The measurements that are taken during the arterial pulse, reflect absorption by arterial blood, nonpulsatile blood, and tissue. The measurements that are obtained between arterial pulses reflect absorption by nonpulsatile blood and tissue.

By correcting "during pulse" absorption for "between pulse" absorption, the NPB-40 determines red and infrared absorption by pulsatile arterial blood. Because oxyhemoglobin and deoxyhemoglobin differ in red and infrared absorption, this corrected measurement can be used to determine the percent of oxyhemoglobin in arterial blood: SpO2 is the ratio of corrected absorption at each wavelength.

S2.2 Functional Versus Fractional Saturation

The NPB-40 measures functional saturation, that is, oxygenated hemoglobin expressed as a percentage of the hemoglobin that is capable of transporting oxygen. It does not detect significant levels of dyshemoglobins. In contrast, some instruments such as the IL282 Co-oximeter measure fractional saturation, that is, oxygenated hemoglobin expressed as a percentage of all measured hemoglobin, including dyshemoglobins.

Consequently, before comparing NPB-40 measurements with those obtained by an instrument that measures fractional saturation, measurements must be converted as follows:

functional saturation

fractional

saturation

100-(% carboxyhemoglobin +%methemoglobin)

100

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Technical Supplement

S2.3 Measured versus Calculated Saturation

When saturation is calculated from a blood gas measurement of the partial pressure of arterial oxygen (PaO2), the calculated value may differ from the NPB-40 SpO2 measurement. This is because the calculated saturation may not have been corrected for the effects of variables that can shift the relationship between PaO2 and saturation.

Figure S2-1 illustrates the effect that variations in pH, temperature, partial pressure of carbon dioxide (PCO2), and concentrations of 2,3-DPG and fetal hemoglobin may have on the oxyhemoglobin dissociation curve.

S3 CIRCUIT ANALYSIS

This section provides an explanation of NPB-40 theory of operation using block diagrams and schematic diagrams.

100

pH Temperature PCO

2,3-DPG

Fetal Hb

pH Temperature PCO

2,3-DPG

Saturation (%)

PO2 (mmHg)

Figure S2-1: Oxyhemoglobin Dissociation Curve

10050

S-2

The NPB-40 consists of three main functional components described in the following paragraphs:

• The CPU PCB block diagram (Figure S3-2) and schematic diagram (Figure S4-3).

• The LCD PCB block diagram (Figure S3-3) and schematic diagram (Figure S4-4).

• The Front Panel PCB schematic diagram (Figure S4-5).

The relationship between these components and their interconnection is illustrated in the NPB-40 block diagram (Figure S3-1).

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Technical Supplement

The following is a list of terms and definitions used in the following paragraphs.

Analog to Digital (A/D) converter. The CPU has a 10-bit A/D converter on board. Up to eight different analog inputs can be provided to the A/D for measurement.

Central Processing Unit (CPU). An Intel 80C196KC 16-bit microprocessor. The CPU sends and receives control signals to the SpO2 analog section, display, and printer infrared LED.

High Speed Outputs (HSO). The 6 HSO lines control most of the timing of the LED signal pulse and the demodulation of the received signal.

Input and Output (I/O). Digital lines that are used by the CPU to read in data and output data.

Light Emitting Diodes (LEDs). Two LEDs are used in Nellcor Puritan Bennett oximetry sensors. Light is transmitted through body tissue and

received by a photodetector circuit that converts it to photocurrent. The two wavelengths, which are used for calculation of pulse rate and oxygen saturation in blood, are transmitted at the following frequencies:

• infrared (IR) light at ≈ 915 microns

• red light at ≈ 660 microns

Pulse Width Modulation (PWM). The three 8-bit PWM outputs can be software controlled; their duty cycle can be changed from 0 TO 99.6 percent of the total pulse duration. PWM frequency is the crystal frequency of the CPU (10 MHz) divided by 1024. The PWMs control the gains within the analog circuit.

RCal. Sensor RCal value is a resistance value specific to an individual sensor. This value is used by the software during oxygen saturation computations to maximize accuracy.

S3.1 Overall Unit Block Diagram Analysis

Exclusive of batteries covers, keys, and external connectors, the NPB-40 consists of three main functional components: the front panel keyboard, the CPU PCB, and the LCD PCB as follows.

• CPU PCB — contains the CPU; power supply circuitry; support memory circuits; sensor circuits for battery voltage; a serial data port; LCD backlight control; pulsatile beeper drive circuits; and some display control circuits.

• LCD PCB — contains the SpO2 analog circuitry and interface to the external sensor; the power conditioning circuitry; the LCD display and display driver circuits; the interface circuitry for the printer (which is not used unless a printer is present); the LCD backlight; and audio output hardware.

• Front Panel Keyboard — contains four membrane switches and a line common to all four switches. This assembly connects to the CPU PCB by a flex circuit.

Refer to Figure S3-1 for this NPB-40 block diagram. The CPU PCB and the LCD PCB are each described in more detail in later paragraphs.

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Technical Supplement

The NPB-40 is powered by four AA-size replaceable alkaline batteries. A dc voltage in the range of 3.6 to 6 Vdc is provided over the life of these batteries. When the voltage from these batteries drops to a level too low to operate the NPB-40, the unit will shut itself off. At that time, the batteries must be replaced.

The front panel keypad contains four keys that provide discrete signals that are monitored by the microprocessor on the CPU PCB. Refer to Figure S4-5 for a schematic diagram of the front panel keypad.

CPU PCB LCD PCB

Batteries

Front panel

keypad

External

serial

interface

3.6-6 Vdc

On/off key

Function

keys

Power

down

External output control

Power control

and PCB

power

CPU

Battery voltage

sense

Raw power

Sensor analog

signal

and

control

Printer

signal

LCD

enable

LCD

data

Power condition and PCB

power

Analog sensor circuits

Printer

IR LED

drive

LCD

Patient sensor input

S-4

External

output

port

Beeper

signal

Backlight

control

Beeper

backlight

Figure S3-1: NPB-40 Block Diagram

LCD

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Technical Supplement

Power from the batteries is controlled and filtered by the power control and PCB power circuits on the CPU PCB. When the On/Off key is pressed on the front panel keypad and the unit is turned off, the power control circuits will turn on the unit. If the unit is on when the On/Off key is pressed, the unit will be turned off. The PCB power circuits provide filtered power for the circuits on the CPU PCB and raw power is passed to the LCD PCB where it is conditioned for the circuits there.

A patient sensor connected to the NPB-40 contains a resistance that is a calibration reference for the sensor. The analog sensor circuits on the LCD PCB then measure the signal from a photodiode in the sensor that is different based on the light absorption characteristics of each patient. That signal is processed by the analog sensor circuits and measured by the CPU. The LED drive signals are then adjusted by the CPU to obtain an optimum signal from the photodiode.

The CPU provides a drive signal for an IR LED on the LCD PCB. When this IR LED is aligned with a receiving photodiode on an external printer, patient data stored in the NPB-40 can be printed.

An external output port on the CPU PCB is controlled by the CPU and sends drive signals to the beeper and LCD backlight and display data to the LCD.

An external serial data interface, used during testing in manufacturing only, is also controlled by the CPU. This interface is only accessible with a special test fixture.

S3.2 CPU PCB Theory of Operation

Refer to Figure S3-2 for the CPU PCB block diagram and to Figure S4-3 for the CPU PCB schematic diagram in the following description. The CPU PCB

hardware and related circuitry, which is illustrated in the following block diagram, includes the following subsystems:

• CPU — A 16-bit microprocessor that includes: a serial port, watchdog timer, A/D converter with an 8-input analog multiplexer, 3-pulse width modulators, and a high speed I/O subsystem.

• System memory — External to the CPU and consists of an 8K x 8 static RAM and a 64K x 16 EPROM.

• Display control — The CPU provides drive and control signals for the LCD driver and display on the LCD PCB.

• Audio output drive— Drives a piezoelectric ceramic beeper on the LCD PCB for audio output.

• Printer drive— The CPU provides a printer drive signal that is applied to an IR LED on the LCD PCB.

• Power supply/Power control circuitry — The NPB-40 receives power from 4 "AA" cell batteries. The power control circuitry discontinues power to the unit when the batteries are no longer reliable.

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Technical Supplement

From batteries

3.6-6 Vdc

From front panel keypad

On/off

key

Shift

key

Display light/

beep on/off

key

Store data/

key

Battery power

Power switch

circuit

Power shut off control

Battery power

feedback

Power on

Battery voltage

sense

RD/WR

AD 0-7

AD 0-15

ALE

Power supply

circuit

RAM

RAM enable

Address

decoding

Address

latch

To LCD PCB

Raw +10 Vdc

Raw

-5 Vdc

VCC (+5 Vdc) To CPU PCB circuits

ADDR

0-12

ADDR

9-15

EPROM enable

ADDR

1-15

VCC

monitor

and

watchdog

reset

circuit

10MHz

clock

circuit

WD RST

Microprocessor

AD 0-7

External

output

port

Analog sensor voltage reference

Analog circuit control signal

External

output

enable

Beeper drive

LCD light enable

LCD CLK,

DATA, CE

LCD enable

Printer LED signal

Analog sensor signal

AD 0-15

To/from LCD PCB

EPROM

Beeper

LCD backlight

LCD driver

Printer interface

V ref

Sensor circuits

S-6

Figure S3-2: CPU PCB Block Diagram

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S3.2.1 CPU

Technical Supplement

The Intel 80C196KC CPU is a 16-bit microprocessor with built-in peripherals including: a serial port, watchdog timer, A/D converter with an 8-input analog multiplexer, three pulse width modulators, two 16-bit counter/timers, up to 48 I/O lines, and a high speed I/O subsystem.

The CPU is capable of running up to 16 MHz, but it is run at 10 MHz for decreased power consumption. All unused inputs are tied to either Vcc or ground through resistors—this prevents unused inputs floating to any voltage and causing excess power drain. The READY input pin is tied high, thereby disabling wait-state generation; all bus accesses are zero wait-state. The EA pin is tied low to enable addressing of the external EPROM.

When the power supply is first switched on by the power control circuit, the watchdog reset circuit holds the CPU RESET pin low for at least 20 ms, then allows the internal pull-up resistor to bring it high; this assures a good CPU reset.

An internal watchdog timer is enabled and runs continuously. The watchdog timer provides a means of recovering from a software upset caused by ESD, EMI, etc.. If the software does not clear the timer at least every 64K state-times (13.1 ms), the CPU will drive RESET low, resetting the entire unit. The reset output by the CPU is only 16 state-times long (3.2 µs).

The CPU has the ability to dynamically switch the data bus width—based on the BUSWIDTH input pin. A low on BUSWIDTH tells the CPU to access memory only 8 bits at a time. When accessing the static RAM, BUSWIDTH is low, automatically reading the 8-bit wide RAM. Since BUSWIDTH is connected to the active low RAM enable line (RAMEN-L), all other memory and mapped I/O are read or written 16 bits at a time.

Eight analog inputs are measured by the CPU. Input from the SpO2 analog section on the LCD PCB includes AC and DC signals for the oximeter sensor red and infrared channels, and the sensor calibration resistor RSENS. The battery voltage and reference voltage from the LCD PCB are also measured.

The CPU is configured as follows:

• Decoded AD0 and BHE generate separate WR write strobes for the low and high bytes of a word. The signal WR (pin WRL) is the low-byte write strobe.

• A standard address latch enable (ALE) is generated and used.

• HSO4 and HSO5 are configured as outputs. The HSO is used to generate stable timing control signals to the SpO2 analog section, display, and printer driver.

• External control pins: P2.2, P2.3, and P2.4 are configured to monitor front panel keyboard keys Store Data/Print, Display Light/Beep On/Off, and Shift keys, respectively.

• Pins HSI0 is configured for interrupt input. The CPU receives one external interrupt (signal PHOTOI).

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Technical Supplement

• P2.0 and P2.1 are configured as a standard asynchronous serial transmitter and receiver for a factory serial interface.

• P2.5, P1.3, and P1.4 are configured as pulse width modulator outputs. They are used with outputs from P1.6 and P2.6 to control gains within the SpO2 analog section.

S3.2.1.1 Address Demultiplexing

U10 and U11 are transparent latches that latch the address portion of the AD bus data on the falling edge of ALE; the outputs are always enabled. The outputs of U10 and U11 are always the address portion of the AD bus.

S3.2.1.2 Address Decoding

The CPU has a 64-Kbyte address range of 0-FFFF. RAM, EPROM, and I/O ports share this space. The address decoding circuit splits up this space and output enable lines to the RAM, EPROM, and external output ports.

When address lines A13, A14, A15 are all high, the output of U7C goes low, enabling the RAM and generates the active low enable signal RAMEN-L. This occurs for the 8K address range of E000-FFFF.

U8 is used to generate the output port active low enable signal EXOUTEN-L. When address lines A15, A14, A11, and A10 are high, and A13 is low, U8 becomes enabled. With U8 enabled, the Y3 output is set low. The output to go low is selected by pins A, B, and C. They form a 3-bit binary number with pin C being the most significant bit. So when address line A12 is high, WR active (low) and RD inactive (high), a binary 3 is produced on pins A, B, and C, forcing output Y3 (EXOUTEN-L) low. This enables the output port for writing. Note that in this condition, A15, A14, A12, A11, and A10 are high and A13 is low.

S3.2.2 CPU Memory

The output port uses the address space of DE00-DFFF. When data is written to that address, the output port enable signal EXOUTEN-L is activated. Because the CPU is configured to use a 16-bit bus, except for RAM, any even address in the DE00-DFFF range could be used for external port access. In other words, reading or writing address DF00, DE02, DE04, etc., will all produce the same results.

U7A generates the EPROMs active low enable signal, ROMEN-L. The active low signals RAMEN-L and EXOUTEN-L are basically used as EPROM disable signals. When RAMEN-L or EXOUTEN-L or the Y3 output of U8 are low, the output of U7A, ROMEN-L, is forced high, disabling the ROM. Therefore, the EPROM is disabled for the range DE00-FFFF and enabled for the address range of 0-DFFF.

The memory system external to the CPU consists of an 8 K x 8 static RAM (U12) and a 64 K x 16 EPROM (U5). The EPROM is 16 bits wide to enhance CPU performance. Because RAM is infrequently accessed, it is only 8 bits wide. U12 is a standard 8K x 8 static RAM.

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The program that the CPU runs is stored in U5. U5 is a 16-bit wide output, one-time programmable (OTP) EPROM. During 16-bit wide bus accesses, the CPU uses address line A0 for low/high byte selection, and is not used as a normal address line. The CPU can only address 64K x 8 bytes or 32K x 16 bytes. Pin A15 of U5 is tied low, always selecting the lower half of the EPROM. Signal ROMEN-L is then used to enable the EPROM for the proper memory area.

The output port external to the CPU consists of an octal D latch, U9. The output of U9 is always enabled. The output bits of U9 control the beeper output, the LCD backlight, and the LCD display drive signals.

S3.2.3 Standard User Controls

The standard user controls consist of four momentary push-button switches on the front panel keypad. These keys are metal dome membrane contact switches.

The front panel switches Store Data/Print, Display Light/Beep On/Off, and Shift are connected to the microprocessor, U4, input lines P2.2, P2.3, and P2.4 and are normally pulled to the high state by R10, R8, and R18. Whenever one of these keys is pressed, the U4 input line is pulled low. The switch contacts are debounced in software.

Technical Supplement

The fourth front panel switch, On/Off, is connected to the power switch described Power Supply/Power Control Circuitry.

S3.2.4 Power Supply/Power Control Circuitry

The power supply and power control circuitry consists of the following primary elements.

• Batteries — Four 1.5 V alkaline "AA" size batteries provide 3.6-6 Vdc power.

• Power entry circuit — Components protect the NPB-40 from damage if batteries are inserted incorrectly and provide reverse current limiting and over-voltage or spike protection. In addition, a self-resetting fuse protects the power supply from excessive current draw. The power supply is also protected against electrostatic discharge and electromagnetic interference.

• Power switch circuitry — This circuit controls power applied to the power supply circuits. Power control circuitry is connected to the batteries. It senses any press of the front panel keypad On/Off key and switches the power supply circuit on or off. A control signal to this circuit from the CPU will also shut off the NPB-40 when battery voltage drops to an unusable level.

• Power supply circuits —consist of a power generation circuit that provides +10Vdc, +5Vdc, and -5Vdc.

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Technical Supplement

S3.2.4.1 Power Entry Circuitry

Self-resetting fuse R22 protects the NPB-40 and will open when current in excess of 0.75 Amps is drawn by the unit. R22 will close when the condition causing excessive current has been eliminated. CR7 provides reverse current protection and limits negative voltages (batteries reversed) to safe levels. In either of these conditions, CR7 will conduct and cause fuse R22 to open. CR5 protects against large voltage transients caused by ESD, EMI, etc. and will pass these undesirable transients to ground.

S3.2.4.2 Power Supply Feedback Circuitry

The power supply feedback circuit consists of Q1 and its associated components. When batteries are installed and the NPB-40 is turned off, the battery voltage (VBAT) is applied through resistor R2 at the collector of Q1 providing a logic 1 level voltage to the D input of flip-flop U1B in the power switch circuit. When the NPB-40 is turned off, VCC is at 0 volts and Q1 is turned off. When the NPB-40 is turned on (See “Power Switch Circuitry”), the VCC potential is applied to the base of Q1, which turns it on. The voltage at the D input of U1B then drops to a low voltage to provide a logic 0.

S3.2.4.3 Power Switch Circuitry

The power control circuit consists of U1B and its associated components. U1B is a D flip/flop with asynchronous preset and clear; only the clear is used. Battery voltage is applied to U1B whenever batteries are installed. The NPB40 is turned on and off by pressing the On/Off key on the front panel keypad.

The BTN PWR line is normally pulled up to the battery voltage by R3. When battery voltage is at an acceptable level and the On/Off key on the front panel keypad is pressed, the BTN PWR line is grounded and the resultant highgoing pulse from U2A toggles the CLK input of U1B and the high D input logic level is transferred to the Q output. The logic state of the D input is controlled by the power supply feedback circuitry (See “Power Supply Feedback Circuitry”). When the NPB-40 is off the D input of U1B is high. Pressing the front panel On/Off key sets the Q output and the PWR ON signal high. This enables the power supply circuits, which then generate the operating voltages for the NPB-40. The Q-not output of U1B is applied to U4 analog to digital converter input P0.6 through a battery voltage sensing circuit consisting of U2B, R14, R17, and C14. When the battery voltage drops below 3.6 Vdc, as measured by U4, the PWR DOWN line at U4 output HSO3 goes high and turns on Q2, which clears flip-flop U1B and the PWR ON signal at the Q output goes low and turns off the power supply circuits.

When the NPB-40 is turned on, the D input of U1B is low (See “Power Supply Feedback Circuitry”). When On/Off key on the front panel keypad is pressed, the BTN PWR line is grounded and the resultant high going pulse from U2A toggles the CLK input of U1B and the low D input logic level is transferred to the Q output. This sets the Q output and the PWR ON signal low, which turns off the power supply circuits.

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S3.2.5 Serial Interface

S3.2.6 Printer Control

Technical Supplement

S3.2.4.4 Power Supply Circuits

When the PWR ON signal at the S/S input of U3 is high, U3 generates a square wave signal that drives the primary winding of transformer T1. The three secondary windings of T1 are rectified and filtered to provide RAW+10V, VCC (+5Vdc), and RAW-5V. The VCC signal is resistor divided by R9 and R12 for a feedback voltage that U3 must see to continue operating. VCC is used on the CPU and the LCD PCBs for operating circuit power. RAW+10V and RAW-5V are supplied to the LCD PCB for backlight power and for power conditioning for the SpO2 analog circuits.

The serial interface is only used for factory test purposes, and is not at the RS-232 level, neither is it electrically isolated and, therefore, cannot be used outside of the factory. The serial data port J5 is a TTL level serial interface. RXD and TXD are configured as a standard asynchronous serial transmitter and receiver at 19.2 Kbaud with 1 stop bit, 8 data bits, and no parity. The serial interface can operate in full duplex mode. If no external serial data device is connected, R19 pulls the RXD input high which prevents the input from floating when it is not being used.

Microprocessor U4 provides a drive signal (IR OUT) at HSO5 that controls an infrared LED on the LCD PCB which is used to interface with an external printer.

S3.2.7 External VCC Monitor and Watchdog Timer

The external VCC monitor and watchdog timer circuit consists of U6 and associated components. U6 provides two functions. If the VCC input voltage drops below 4.0 Vdc, U6 will drive the RST-L line low, which resets microprocessor, U4. U6 also periodically receives the WD RST pulse output from U4. If U6 does not receive the WD RST signal at least every 500 ms, it will drive the RST-L line low, which resets U4.

S3.3 LCD PCB Theory of Operation

Refer to Figure S3-3 for the LCD PCB block diagram and to Figure S4-4 for the LCD PCB schematic diagram in the following description. This subsection

describes the SpO2 analog hardware. The analog circuitry has high signal sensitivity and reduced susceptibility to noise. Its design allows for a wide range of input signal levels and a broad range of pulsatile modulation. The SpO2 analog circuitry consists of four subsections:

• Sensor output/LED control —The CPU controls the gain of both LEDs so that signals received at the input amplifier are within an acceptable dynamic range. Signal channel gain may also need to be increased. The CPU uses Pulse Width Modulation (PWM) lines to control LED current level or to amplify the signal channel.

• Input conditioning —Sensor output current is converted to voltage. A demodulation circuit minimizes the effects of other light sources and stray frequency inputs. Because the IR and RED signals are at different current levels, the two LED signals are demultiplexed and separately amplified, so they can be compared with each other. Two circuits handle the demultiplexing by alternately selecting LED signals using switches.

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Technical Supplement

Filters then remove noise and smooth the signals before sending them to the amplifiers.

• Signal gain —The separated LED signals are amplified so that their

current levels are within the A/D converter's acceptable range. The signals are filtered to improve the signal-to-noise ratio, and clamped to a reference voltage.

• AC ranging —DC offset is eliminated from each LED signal. An

analog switch sets the mean signal value to the mean of the A/D converter range, and the AC modulation is superimposed on that DC level. Then, each AC signal is amplified and filtered to eliminate residual effects of the PWM modulations. Finally, these two signals are input to the CPU A/D converter.

S-12

Page 45

Technical Supplement

The relationship between these subsections is shown in the LCD PCB block diagram, Figure S3-3.

To/from CPU PCB

Raw +10 Vdc

Raw -5 Vdc

V ref

Printer

LED signal

LCD clock

LCD data

LCD enable

LCD light enable

Power

conditioning

LCD

driver

+10Vdc

-5 Vdc

Printer

IR LED

LCD

Beeper drive

Analog sensor

signal

Analog circuit

control signals

Red

channel

LED

drive

To/from patient sensor

LED drive

RSENS

Photodiode

LCD

backlight

Beeper

Sensor

D-connector

S3.3.1 Sensor Output/LED Control

The SpO2 analog circuitry provides control of the red and IR LEDs such that the received signals are within the dynamic range of the input amplifier. Because excessive current to the LEDs will induce changes in their spectral output, it is sometimes necessary to increase the received signal channel gain. To that point, the CPU controls both the current to the LEDs and the amplification in the signal channel.

Figure S3-3: LCD PCB Block Diagram

S-13

Page 46

Technical Supplement

At initialization of transmission, the LEDs' intensity level is based on previous running conditions, and the transmission intensity is adjusted until the received signals match the range of the A/D converter. If the LEDs reach maximum output without the necessary signal strength, the PWMs will increase the channel gain. The PWM lines will select either a change in the LED current or signal gain, but will not do both simultaneously.

The LED drive circuit switches between red and IR transmission and disables both for a time between transmissions in order to provide a no-transmission reference. To prevent excessive heat build-up and prolong battery life, each LED is on for only a small portion of the duty cycle. Also, the frequency of switching is well above that of motion artifact and not a harmonic of known AC transmissions. The LED switching frequency is 1.485 kHz. The IR transmission alone, and the red transmission alone, will each be on for about one-fifth of the duty cycle; this cycle is controlled by the HSOs of the CPU.

The IR and red LEDs are separately controlled with their drive currents multiplexed over two shared wires. Current to the IR LED is in the range of

4.3-50.0 mA; and, current to the red LED is in the range of 4.3 to 50 mA.

Currents are limited to less than 100 mA for two reasons: (1) slight excess current can potentially change the emission characteristics of the LEDs, and (2) large excess current could create excessive heat at the sensor site.

The IR/red LED transmission signal (HSO1 of the CPU) is fed into the select inputs of the triple single-pole-double-throw (SPDT) analog multiplexing switch U7, causing either the IR or the red LED transmission to be enabled.

PWM1, which is filtered by the network of R45, R35, C41, and C42, is input to the LED drive circuit switch U7 and controls the magnitude of the IR LED current supply.

PWM2, which is filtered by the network of R29, R39, C35, and C23, is also input to U7 and controls the red LED current magnitude.

Two NPN transistors (Q8 and Q10) act as current sources for the IR and red LED outputs. Two PNP transistors (Q9 and Q11) act as switches between the IR and red LED output lines. Transistor Q12 acts as an LED drive current limiter; it clamps the output of the current regulator circuit to the required level. If any resistor in the LED drive circuit fails, current to the LED will still be limited to a safe level.

The RSENS line senses the RCal value and enables the CPU to make the proper calculations based on the type of sensor being used.

S3.3.2 Input Conditioning

Input to the SpO photodiode. In order to condition the signal current, it is necessary to convert the current to voltage.

A differential synchronous demodulation circuit is used to reduce the effects of other light sources and stray frequency inputs to the system. Because the IR and red signals are absorbed differently by body tissue, their received signal intensities are at different levels. Therefore, the IR and red signals must be demodulated and then amplified separately in order to compare them to each other. Demultiplexing is accomplished by means of two circuits that alternately select the IR and red signal. Selection of the circuits is controlled by two switches that are coordinated with the IR and red transmissions. A filter with a large time constant follows to smooth the signal and remove noise before amplification.

2 analog circuit is the current output of the sensor

S-14

Page 47

Technical Supplement

Before the current from the photodetector is converted to voltage, any high frequency noise is filtered by C9 and R21. The op-amp U5A is used in parallel with the current-to-voltage converter U5B to cancel any DC voltage, effectively AC coupling the output of U5B. The average value of the SpO

analog reference voltage (VREF) of U5B, 5 V, is measured at test point 6. U3B, a single-pole-single-throw (SPST) analog switch, is controlled by the

same line that controls the on/off pulsing of the LEDs. When either of the LEDs are on (the line is low and the switch is closed) U4B is used as a noninverting amplifier. When the LEDs are both off, U4B is used an inverting amplifier. The signal at the output of amplifier U4B is then demultiplexed.

The CPU HSO lines SAMPRED and SAMPIR, which are both active low, control SPST analog switches in U3A and U3C respectively. Switch U3A is closed to sample the red signal; switch U3C is closed to sample the IR signal. The sampling rate for both switches is 10 kHz. Switching is coordinated with the LED transmission so that the IR and red signals are each sampled twice per cycle; that is, once when the LED is off (signal inverted), and once when the LED is on (signal not inverted). The filtering circuit that follows has a long time constant, thereby acting as an averaging circuit.

If the instantaneous average photocurrent (DC offset) is excessive and U5B cannot bring it to VREF, the PHOTOI line to the CPU (HSI0) is activated. This action is an indication of excess ambient light into the photosensor, or the occurrence of excess noise in the input circuit. It also serves as a warning to the instrument that the sensor signal may be contaminated and causes the software to send an error message.

S3.3.3 Signal Gain

The separated IR and red signals are amplified so that their DC values are within the range of the A/D converter. Because the received IR and red signals are typically at different current levels, the signal gain circuits provide independent amplification for each signal as needed. The gain in these circuits is adjusted by means of the PWM lines.

After the IR and red signals are amplified, they are filtered to improve the signal-to-noise ratio and clamped to a reference voltage to prevent the combined AC and DC signal from exceeding an acceptable input voltage from the A/D converter.

S3.3.3.1 Variable Gain Circuits

The two variable gain circuits are functionally equivalent. The gain of each circuit is contingent upon the signal’s received level and is controlled to bring each signal to approximately 3.5 V. Each circuit uses an amplifier and one switch in the triple SPDT analog multiplexing unit U9.

The gain in each of the circuits is accomplished by means of a feedback loop, which includes one of the SPDT switches in U9. The PWMs control whether the feedback loop is connected to ground or to the amplifier output. The feedback is then averaged by C17/R27 (red), and C20/R26 (IR). The higher the value of PWM2, the greater the IR gain; the higher the value of PWM1, the greater the red gain.

S-15

Page 48

Technical Supplement

S3.3.4 AC Ranging

S3.3.3.2 Filtering Circuits

These circuits consist of two cascaded second-order filters with a break frequency of 10 Hz. Diodes (CR1/CR2 for the red channel, CR4/CR3 for the IR channel) connected to VREF and ground at the positive inputs of the second amplifiers, maintain the voltage output within the range of the A/D converter.

In order to achieve a specified level of oxygen saturation measurement and to still use a standard-type combined CPU and A/D converter, the DC offset is subtracted from each signal. Because the DC portion of the signal can be on the order of one thousand times the AC modulation, 16 bits of A/D conversion would otherwise be required to accurately compare the IR and red modulations between the combined AC and DC signals. The DC offsets are subtracted by using an analog switch to set the mean signal value to the mean of the range of the A/D converter whenever necessary. The AC modulation is then superimposed upon that DC level. This is also known as AC ranging.

Each AC signal is subsequently amplified such that its peak-to-peak values span one-fifth of the range of the A/D converter. The amplified AC signals are then filtered to remove the residual effects of the PWM modulations and, finally, are input to the CPU. The combined AC and DC signals for both IR and red signals are separately input to the A/D converter.

S3.3.5 Audio Output

S3.3.4.1 Offset Subtraction Circuits

Voltage dividers R53 and R49 (red), and R61 and R63 (IR), which are located between VREF and ground, establish a baseline voltage of 2.75 V at the input of the unity gain amplifiers U12C (red) and U12D (IR).

Whenever SPST analog switches U11A and U11D are closed by HSO0 (active low), the DC portions of the IR and red signals create a charge, which is stored on C54 and C46, respectively. These capacitors hold this charge even after the switches are opened and the resulting voltage is subtracted from the combined signal — leaving only the AC modulation output. This AC signal is superimposed on the baseline voltage output by U12C and U12D. The IRDC and REDDC are then filtered and input to the microprocessor on the CPU PCB.

S3.3.4.2 AC Variable Gain Control Circuits

The AC modulations are amplified by U12A (red) and U12B (IR) and superimposed on the baseline voltages present at the output of U12D (IR) and U12C (red). The amplification is handled by means of the SPDT analog multiplexing switch U13 within the feedback loop, which increases gain as PWM0 is increased. The IRAC and REDAC are then filtered and input to the microprocessor on the CPU PCB.

S-16

LS1, a piezo ceramic sounder, is the audio output device. Due to its low drive current of 2 mA maximum, no drive circuitry is needed and is driven directly from the external output port. It is differentially driven with 2 square waves 180 degrees out of phase. The drive frequency is approximately 1480 Hz or 740 Hz and is generated by the CPU. LS1 is differentially driven to obtain maximum audible volume.

Page 49

S3.3.6 Display Control Circuitry

The LCD CE, LCD CLK, and LCD DATA from external output port U9 and LCD EN from the microprocessor on the CPU PCB are connected to the LCD drive IC, U1. U1, in turn, drives the individual segments of the LCD. The microprocessor drives LCD CE and LCD EN high, connected to the U1 CE and INH inputs, respectively. At that time, data on the LCD DATA line is clocked into U1 by the LCD CLK line. U1 then decodes the data input and turns the proper segments on or off on the LCD. The INH inhibit input of U1 is held low by resistor R9 until the line is driven high by the LCD EN signal from microprocessor on the CPU PCB. This assures that the display is blanked until it is under microprocessor control. Should the microprocessor be reset, the LCD EN line goes to a floating state, R9 then pulls the INH input to U1 low, and the display is blanked.

S3.3.7 Power Conditioning Circuitry

Unfiltered positive (RAW+10V) and negative (RAW-5V) voltages from the CPU PCB are applied to the power conditioning circuit. RAW+10V is filtered by a circuit consisting of R6, C1, and C2 to provide a clean and stable +10 V dc operating voltage for LCD PCB SpO RAW-5V is filtered by a circuit consisting of R11, C8, and C10 to provide a clean and stable -5 V dc operating voltage for the LCD PCB circuits. A filtered +5Vdc (VCC) from the CPU PCB is also used as VCC by circuits on the LCD PCB.

Technical Supplement

2 analog and other circuits. Likewise,

S3.3.8 Analog Reference Voltage

RAW +10V from the CPU PCB is applied to a filter consisting of R7 and C6 to create VIN that is used by voltage converter U2 to create VREF. U2 provides an accurate, regulated voltage that is used as the reference voltage for the A/D inside the microprocessor U4 on the CPU PCB. Filtering is provided by C7, C9, and R12. The voltage output VREF is + 5 Vdc.

S3.3.9 LCD Backlighting

RAW+10V from the CPU PCB is used as power for the LCD backlight. The LCD backlight consists of LEDs DS1 through DS6. Resistors R3 and R4 provide current limiting for the LEDs. Transistor Q2 is turned on when the LCD LIGHT signal from external output port U9 on the CPU PCB goes high which, in turn, illuminates the backlight LEDs.

S3.3.10 Printer Drive Circuit

The printer drive circuit consists of R1, R2, Q1, and DS7. The IR OUT signal from microprocessor U4 on the CPU PCB controls transistor Q1 which, in turn, controls infrared LED DS7. DS7 is used to provide a data signal that is transmitted to an external printer with an infrared receiver.

S-17

Page 50

Technical Supplement

S4 SCHEMATIC DIAGRAMS

The following part locator diagrams and schematic diagrams are included in this section:

Figure Description

Figure S4-1 CPU PCB Parts Locator Diagram Figure S4-2 LCD PCB Parts Locator Diagram Figure S4-3 CPU PCB Schematic Diagram Figure S4-4 LCD PCB Schematic Diagram Figure S4-5 Front Panel Keypad Schematic

Diagram

S-18

Page 51

034311

TOP SIDE BOTTOM SIDE

Figure S4-1

CPU PCB Part LocatorDiagram

FOS S5-1

Page 52

034315

TOP SIDE BOTTOM SIDE

Figure S4-2

LCD PCB Parts Locator Diagram

FOS S5-3

Page 53

BT2

BT1

Power Supply Feedback

VBAT

10.0K

BTN_PWR

0.1U

82.5K

R18

10.0K

1 2 3 4 5

MEMBRANE SWITCH CONNECTOR

VCC

R10

10.0K

POWER ENTRY

SELF RESETTING FUSE

BAT+

BAT-

150K

CR1

1N914S

0.1U

BTN_SHIFT

ADDRESS DECODING

WR-L

ADDR9 ADDR10 ADDR11 ADDR12 ADDR13 ADDR15 ADDR14

VCC

C35 1000P 5%

AD1 ADDR1 AD2 ADDR2 AD3 ADDR3 AD4 ADDR4

AD5 ADDR5 AD6 ADDR6 AD7 ADDR7

ALE

ADDR_TRI

TP54

R21

10.0K

AD9 ADDR9 AD10 ADDR10 AD11 ADDR11 AD12 ADDR12 AD13 ADDR13 AD14 ADDR14 AD15 ADDR15

ALE

ADDR7

10 ADDR6 ADDR5 ADDR4 ADDR3 ADDR2 ADDR1 ADDR0

ADDR8 ADDR9

24 ADDR10

21 ADDR11

23 ADDR12

WR-L

RD-L

20 14

RAMEN-L

STATIC RAM

VCC

ADDR1 ADDR2 ADDR3 ADDR4 ADDR5 ADDR6 ADDR7 ADDR8 ADDR9 ADDR10 ADDR11 ADDR12 ADDR13 ADDR14 ADDR15

ROMEN-L RD-L

2 3

6 4 5

U7B

654

74HC10S

VCC

C24

C20

0.1U

U10

192AD0

183

174

4D 4Q

156

5D65Q

147

6D76Q

138

7D87Q

129

8D98Q

74HC573S

U11

192AD8

183

174

165

156

5D65Q

147

6D76Q

138

7D87Q

129

8D98Q

74HC573S

U12

PWR

5 4

4 3

A10

A11

A12 CE2/A13 NC/A14

WE OE

GND

5565S

PWR

A10

A11

A12

A13

D10

A14

D11

A15

D12

N.C.

D13 D14

D15

PGM

GND1

VPP

GND2

27C1024

EPROM

A B C

G1 G2A G2B

74HC138 - SMT

U7C

9 10 11

74HC10S

ADDR0

VCC

ADDR8

VCC

AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7

9 8 7 6 5 4

34 12

TP51

Y1 Y2 Y3 Y4 Y5 Y6 Y7

R20

10.0K

VCC

C22

0.1U

C27 47U 10V

7343

AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7 AD8 AD9 AD10 AD11 AD12 AD13 AD14 AD15

13 12 11 10 9 7

ROM_DIS-L

DE00 - DFFF

EXOUTEN-L

TP41

E000 - FFFF

RAMEN-L

TP40

U7A 1 2

74HC10S

ROMEN-L

0000 - DFFF

TP39

VCC

C34 1000P

C19

0.1U

TEST POINTS

ADDR0 ADDR1 ADDR2 ADDR3 ADDR4 ADDR5 ADDR6 ADDR7 ADDR8 ADDR9 ADDR10 ADDR11 ADDR12 ADDR13 ADDR14

C36 1000P

C25

0.1U

ADDR15

ALE RD-L WR-L

SCOPE PROBE GROUND

USE J2 PINS FOR TEST POINTS OF VCC, RAW+10V, RAW-5V

SERIAL INTERFACE

RXD

C13

C26 47U

0.1U 10V

7343

REDDC

IRDC

RSENS RAW-5V

PWM0

FACTORY TEST

POGO DATA CONTACTS

LCD BOARD INTERFACE

VREF

AD0

TP30 TP43 TP31 TP44 TP32 TP45 TP33 TP46 TP34 TP47 TP35 TP48 TP36 TP49 TP37 TP50

TP6 TP8

TP42

TP55

VCC

R19

10.0K

TP23

TP26

43 65 87

10 1211 1413 1615 1817 20

TP9

AD1

TP11

AD2

TP10

AD3

TP14

AD4

TP15

AD5

TP17

AD6

TP20

AD7

TP19

AD8

TP18

AD9

TP16

AD10

TP12

AD11

TP22

AD12

TP21

AD13

TP25

AD14

TP24

AD15

TP29

CLINICAL SERIALTXD

2 3

DATA CONNECTOR 4 5

VCC

REDAC

IRAC RAW+10V

LEDDIS

1000P

U2B 74HC14S 4

TP53

LT1373CS8

MAN_RST

VIN

VSW

VFB

NFB

11.5K

TP4

PBRST

TOL

GND

LTC1232

PWR_ON

S/S

R14

15.8K

R17

47.5K

GNDS

GND

SEPARATE VIAS TO GROUND PLANE FOR PINS 6 & 7

TP7

C14

0.1U

TP52

C11

0.1U

C28

R13

4.99K

SW_VBAT

R22

0.75A

CR7

CR5

MBRS330T3

VBAT

R2 150K

PWR_FB

Q1 2N3904S

VBAT

U2A

74HC14S 2

SMCJ10C

TP1

U1B

CLK

74HC74S

VBAT

TP2

VBAT

VCCQPRE

PWR_ON

GNDDCLR

CR6

1N914S

C16 10U 16V

6032

VBAT

POWER SWITCH CIRCUIT

VBAT

10.0K

BTN_2

BTN_1

150K

0.1U

2N3904S

TP3

R11

150K

PWR_DOWN

CURRENT

36.5K

VCC

~RST

RST

VBAT

C2 330P

49.9

HIGH

R12

VCC

POWER SUPPLY CIRCUIT

C23 47U 10V

7343

PLACE C23 AND C1

NEAR T1 PIN 2

1000P

TP5

WD_RST

TP38

10.0K

N/C

T1 LPE-4841

0.1U

C31

R24 221

VCC

C18

0.1U

REDDC REDAC IRDC IRAC RSENS BAT_VOLTBAT_VOLT

LEDDIS IR/RED RWD_RST PWM1 PWM2

IRLED/AV

RST-L

RAMEN-L PHOTOI

TXD RXD BTN_2 BTN_1 BTN_SHIFT PWM0 REDLED/AV ZERO-L

CR3

MBRS130

CR2

MBRS130

C7 47U 10V

7343

CR4

MBRS130

C12 47U 10V

7343

VREF

PWR

VPP

VREF

ANGND

ACH0/P0.0

ACH1/P0.1

ACH2/P0.2

ACH3/P0.3

ACH4/P0.4

ACH5/P0.5

ACH6/P0.6

ACH7/P0.7

P1.0

P1.1

P1.2

P1.3/PWM1

P1.4/PWM2

P1.5/

P1.6/

P1.7/

READY

RESET

NMI

BUSWIDTH

HSI0

HSI1

P2.0/TXD

P2.1/RXD

P2.2/EXTINT

P2.3/T2CLK

P2.4/T2RST

P2.5/PWM0

P2.6/TWUP-DN

P2.7/T2CAPT

C29

0.1U

80C196KC

C30

1000P

PLACE BY U4 PIN 14 PLACE BY U4 PIN 36

RAW+10V

VCC

22U 20V

7343

RAW-5V

C4 47U 10V

7343

RP2 120

RAD0

AD0

RAD1

AD1

RAD2

AD2

RAD3

AD3

RAD4

AD4

RAD5

AD5

RAD6

AD6

RAD7

AD7

RAD8

AD8

RAD9

AD9

RAD10

AD10

RAD11

AD11

RAD12

AD12

RAD13

AD13

RAD14

AD14

RAD15

AD15

ADV

ALE/

RRD-L

RWR-L

WRL/WR

WRH/BHE

HSI2/HSO4 HSI3/HSO5

CLKOUT

VCCVCC

41 63

INST

HSO0

HSO1

HSO2

HSO3

26 27

CLK_OUT

XTAL1

XTAL2

GND1

GND2

GND3

C33

0.1U

BREQ HLDA HOLD

C17

C32

1000P

0.1U

AD0

AD1 AD2

AD3

6811

AD4

AD5

AD6

AD7

AD8

AD9

AD10

10 11

AD11 AD12

AD13

AD14

AD15

ALE

120

RP1

R25 121

RD-L

121

WR-L

R26

SAMPRED

OFF/ON SAMPIR

PWR_DOWN

LCD_EN IR_OUT

TP13

Y2 R15 121

10MHZ

HC49S

10MHZ

ATP-SM

C10 22P

Y2 IS USED ONLY IF Y1 IS NOT AVAILABLE

C9 22P

VCC

R23

TP56

10.0K

BIGRAM

Note: Populate U12 with 8Kx8 (143101) or 32Kx8 (143102).

NOTES:

1. ALL CAPACITORS ARE 10% 50V 1206 PACKAGE UNLESS OTHERWISE NOTED.

2. ALL RESISTORS ARE 1% 1/8W 1206 PACKAGE UNLESS OTHERWISE NOTED.

UNUSED GATES

VCC

R16

TP27

10.0K

BIGROM

J4 0

034310

Note: To populate U5 with 64Kx16 (143003) or 128Kx16 (143010)

U1A

74HC74S

VBAT

VCCQPRE

CLK

GNDDCLR

VBAT

U2C 74HC14S 6

VBAT

U2D 74HC14S 8

VBAT

U2E 74HC14S 10

VBAT

U2F

74HC14S 12

parts, do not populate location J4

To populate U5 with 256Kx16 (143011,171259), populate J4.

EXTERNAL OUTPUT PORT

AD0 AD1 AD2 AD3 AD4 AD5 AD6 AD7

EXOUTEN-L

SAMPRED PHOTOI

SAMPIR

CLK

74HC574S

BEEP_1

BEEP_2

LCD_CE

LCD_CLK

LCD_DATA

LCD_LIGHT

VCC

C21

0.1U

IR/RED LCD_EN LCD_CE BEEP_1 LCD_DATA LCD_CLK REDLED/AV ZERO-L

PWM1

BLM31B06

FSAMPRED

FSAMPIR

FPWM1

FPWM2

FIRLED/AV

65 87 10 1211 14 1615 1817 20219

FOFF/ON

BLM31B06

LCD_LIGHT

PWM2

IR_OUT

IRLED/AV

BEEP_2

OFF/ON

Figure S4-3

CPU PCB Schematic Diagram

FOS S5-5

Page 54

AD822 BYPASS

+10V

-5V

VREF

R15

2.00K

R18

1.00M

DG201S BYPASS

+10V

-5V

390P

3.32K

TP7

SENSOR INPUT

CONNECT CGND TO AGND WITH SEPARATE TRACE TO J2.2

DB9FB

5 9

9 4

4 8

8 3

3 7

7 2

2 6

6 11

TO CASE EMI PAINT

BOSS HOLES DB9 RIB

BLM31B06

H2 H3

RIGHT SIDELEFT SIDE

VREF

U14A 74HC00S

VREF

U14B 74HC00S

C11

0.01U

C13

0.01U

88.7K_0.1%

R14

51.1K

C14 22U

20V

7343

VREF

C19

R25

R17

88.7K_0.1%

GNDV-

U3B

DG201S

U5B AD822

R21

3.32K

C12 18P

R20

182K

U5A

AD822

TP18

VREF

C27 100P

TP10

R13

+10V

U4B

AD822

-5V

TP6

+10V

V+

-5V

+10V

875

-5V

R16

1.00M

+10V

813

-5V

C25 100P

6.04K_0.1%

U3C

DG201S

U3D

DG201S

R19 280K

C22

0.047U

TP16

RSENS

C34 100P

VREF

R51

C36

0.1U

Z5U

0.047U

GNDV-

C18

R22

511K

VCC

C24

0.01U

-5V

R26

82.5K

+10V

V+

U3A

DG201S

-5V

+10V

V+

-5V

+10V

V+

-5V

VREF

C40

0.1U

Z5U

R30

10.0K

Q10

MPSA06S

R36

10.0

VCC

Q9 MPSA56S

IR/RED

616

INHVCC

R27

82.5K

313

TP17

R48

10.0K

VEE

VSS

CD4053S

MPSA06S

10.0K

TP29

Q11

MPSA56S

R47

1215

XOY

VCC

TP2

R41

10.0K

R37

2.74K

R46

10.0K

R66

2.74K

R40

22.1K

VREF

C17 1000P

2N3906SQ51

R24

3.32K

C21

0.47U 25V

3216

C20 1000P

2N3906S 1

R23

3.32K

C15

0.47U 25V

3216

11 10

2 1

5 3

Q7 2N3904S

C29

0.1U

Z5U

VREF

VCC

INH VCC A B C

XO Y X1

Y0 Y1

Z0 Z1

CD4053S

RED CHANNEL

C30

0.12U

R38

VREF

100K

C16 220P

+10V

U4A

AD822

TP1

-5V

VREF C23 220P

+10V

LF441S

47851

478

TP24

-5V

C28

0.01U

166

1512

VEE

VSS

TP15

IR CHANNEL

R56

100K

LED DRIVE

U6B

LT1013S

R33

100K

C31

0.068U

C51

0.12U

R58

100K

C50

0.068U

VCCVCC

C33

4.7P

TP20

+10V

U10C LF444CM

984

CR1 1N914S

1 331

-5V

TP22

+10V

U10A LF444CM

412

CR4 1N914S

1 313

-5V

R73 100K

22PC60

3 13

R71

CR5 1N914S

100K

R72

100K

331

1N914SCR6

C39

0.12U

100K

0.022U

VREF

CR2

1N914S

R34

100K

C38

0.12U

VREF

CR3

1N914S

R42

100K

R29

C35

0.1U

C26

0.068U

TP27

13 13

C32

TP21

1331

C37

R32 182K

R39

20.0K

+10V

41413

U10D LF444CM

-5V

+10V

674

U10B LF444CM

-5V

TP13

R45

100K

C41

0.1U

C42

0.022U

U11A

DG201S

U11D

DG201S

R43 182K

R35

20.0K

GNDV-

TP14

R44

100K

R52

100K

Q12

2N3906S1

3.32K

C46

0.015U 1825

VREF

+10V

R53

12.1K

V+

TP23

-5V

R49

15.0K

3.32K

C54

0.015U 1825

VREF

+10V

R61

12.1K

V+

TP26

-5V

R63

15.0K

VCC

+10V

V+

GNDV-

-5V -5V

R57

C49

0.01U

+5.7V

U12A LMC6044S

41110

+5.7V U12C LMC6044S

12114

R59

C52

0.01U

+5.7V

U12B LMC6044S

+5.7V U12D LMC6044S

4113

VCC VCC

DG201S

R50

3.32K

C45

C44

0.47U

0.1U

25V

R60

3.32K

C47 1000P

R55

34.8K

3.32K

C55 1000P

R67

34.8K

3.32K

+10VVCC

V+

GNDV-

4U11C

U11B

DG201S

C59

0.01U

R54

100K

R64

C58

0.01U

R65

C63

0.01U

R62

100K

R70

C62

0.01U

OFF/ON

R31

15.8K

3216

U13

VCC

616

INH VCC

12 15

XO Y

R68

3.32K

REDLED/AV

+10V

C43

0.01U

C53

0.01U

-5V

VREF

TP12

R28

40.2K

NOTES:

1. ALL CAPACITORS ARE 10% 50V 1206 PACKAGE UNLESS OTHERWISE NOTED.

2. ALL RESISTORS ARE 1% 1/8W 1206 PACKAGE UNLESS OTHERWISE NOTED.

0.47U

3216

U14C 74HC00S

U14D 74HC00S

CD4053S

C57

25V

VCC

C61

0.01U

VEE

VSS

VREF

C48 22U 20V

7343

VCC

C56

0.1U

DG201S BYPASS

U6A

LT1013S

C64

0.01U

PWM2

OFF/ON

SAMPIR

SAMPRED

IRLED/AV

ZERO-L

REDDC

REDAC

PWM0 REDLED/AV

IRDC

IRAC

PWM1

IR/RED

LEDDIS

PHOTOI

RSENS

VCC

47U 10V

7343

51.1K

LCD_CE

LCD_CLK

LCD_DATA

LCD_EN

51.1K

LCDCOM

SEG12

RAW+10V

RAW-5V

LCD BACKLIGHT IR PRINTER LINK

604

DS3

AA1101W

DS5

AA1101W

DS1

AA1101W

LCD_LIGHT

4.75K

PHOTOI SAMPIR IR/RED LCD_EN LCD_CE LCD_DATA REDLED/AV

PWM1

VDD

VLCD

0.01U

VSS

680P

0805

OSC

SCL

INH

TP11

TP8

NJU6432B

182

C6 22U 20V

7343

TP3

49.9

22U

0.1U 20V

Z5U

7343

TP5

R11

49.9

C10

22U

0.1U 20V

Z5U

7343

RAW+10V

R3 604

AA1101W

121

Q2 2N3904S

VCC VREF

REDDC

IRDC

RSENS RAW-5V

PWM0

AGND and DGND for board set are connected together on CPU board

COM1 COM2 SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8

SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27 SEG28 SEG29 SEG30 SEG31 SEG32 SEG33 SEG34 SEG35 SEG36 SEG37 SEG38 SEG39 SEG40 SEG41 SEG42 SEG43 SEG44 SEG45 SEG46 SEG47 SEG48 SEG49 SEG50 SEG51 SEG52 SEG53

VIN

+10V

10.0K

-5V

2N3904S

TP19TP9

DS6

DS2

DS4

CPU INTERFACE

1 3 4 5 6 7 8

99 11 12 13 14 15 16 17 18 19220

3 4

5 6

7 8

99 11 12 13 14 15 16 17 18 19220

64 63

63 1

1 2

2 3

3 4

4 5

5 6

6 7

7 8

8 9

9 10

10 11

11 12

12 13

13 14

14 15

15 16

16 17

17 18

18 19

19 20

20 21

21 22

22 23

23 25

25 26

26 27

27 28

28 29

29 30

30 31

31 32

32 33

33 34

34 35

35 36

36 37

37 38

38 39

39 40

40 41

41 42

42 43

43 44

44 45

45 46

46 47

47 48

48 49

49 50

50 51

51 52

52 53

53 54

POWER ENTRY

VIN VOUT

GND1

GND2

78L05D

R10

IR_OUT

2 43 65 87 10

10 1211 1413 1615 1817 20

2 43 65 87 10

10 1211 1413 1615 1817 20

SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27 SEG28 SEG29 SEG30 SEG31 SEG32 SEG33 SEG34 SEG35 SEG36 SEG37 SEG38 SEG39 SEG40 SEG41 SEG42 SEG43 SEG44 SEG45 SEG46 SEG47 SEG48 SEG49 SEG50 SEG51 SEG52 LCDCOM

121

LCD FLEXTAILLCD DRIVER

SEG52 SEG51 SEG50 SEG49 SEG48 SEG47 SEG46 SEG45 SEG44 SEG43 SEG42 SEG41 SEG40 SEG39 SEG38 SEG37 SEG36 SEG35 SEG34 SEG33 SEG32 SEG31 SEG30 SEG29 SEG28 SEG27 SEG26 SEG25 SEG24 SEG23 SEG22 SEG21 SEG20 SEG19 SEG18 SEG17 SEG16 SEG15 SEG14 SEG13 SEG12 SEG11 SEG10 SEG9 SEG8 SEG7 SEG6 SEG5 SEG4 SEG3 SEG2 SEG1

121

LCD_LIGHTSAMPRED PWM2 IR_OUT IRLED/AV BEEP_2 BEEP_1 LCD_CLK ZERO-L

OFF/ON

0.1U

Z5U

VCC

REDAC

IRAC RAW+10V

LEDDIS

1 2

2 3

3 4

4 5

5 6

6 7

7 8

8 9

10 11

11 12

12 13

13 14

14 15

15 16

16 17

17 18

18 19

19 20

20 21

21 22

22 23

23 24

24 25

25 26

26 27

27 28

28 29

29 30

30 31

31 32

32 33

33 34

34 35

35 36

36 37

37 38

38 39

39 40

40 41

41 42

42 43

43 44

44 45

45 46

46 47

47 48

48 49

49 50

50 51

51 52

52 53

53 5454

N40LCD

R12

1.0

TP28

VREF

DS7

LTE-302

TP4

R2 182

Q1 2N3904S

LS1

AT-17

C7 22U 20V

7343

LCDCOM

VREF

GND3

GND4

TP25

+5.7V

Q4 2N3904S

10.0K

PIEZO

BEEP_1

BEEP_2

034314

Figure S4-4

LCD PCB Schematic Diagram

FOS S5-7

Page 55

To CPU PCB J3

Keypad Schematic Diagram

Figure S4-5

FOS S5-9