Enhance SFX12V Version 2.3 Power Supply Design Guide

SFX12V Power Supply Design Guide

Version 2.3

Revision History

Version Release Date Notes

1.0 Dec, 1997 Public release

1.1 Apr, 1998

2.0 May, 2001 • Added SFX12V description

2.1 Aug, 2001 • Section 4.4 Updated Figure 4 SFX/SFX12V Connectors

• Updated all mechanical outlines to clean up dimensioning of mounting holes.

• Added chassis cutouts for all mechanical outlines to clarify keep-out areas.

• Added Appendix C.

• Additional power ratings added

• Updated industry standards

• Increased standby current

• Section 5.8 removed vendor name

2.2 Dec, 2001 • Section 3.23 Typical Power Distribution. Change minimum loading on 5V rail to 0.3A

• Section 3.3.2 PS_ON#. Add text “The power supply should not latch into a shutdown state when PS_ON# is driven active by pulses between 10ms to 100ms during the decay of the power rails.”

2.3 April, 2003 • Reformat and update revision table

• Update Disclaimers

• Remove guidelines for SFX without 12V connector

• Updated power and current guidance

• Added efficiency targets for light and typical loading

• Increased minimum Efficiency at full load from 68% to 70%

• Updated guidance for standby efficiency

• Added Serial ATA connector

• Updated cross regulation graphs

SFX12V Power Supply Design Guide Version 2.3

IMPORTANT INFORMATION AND DISCLAIMERS

INTEL CORPORATION (AND ANY CONTRIBUTOR) IS PROVIDING THIS INFORMATION AS A CONVENIENCE AND ACCORDINGLY MAKES NO WARRANTIES WITH REGARD TO THIS DOCUMENT OR PRODUCTS MADE IN CONFORMANCE WITH THIS DOCUMENT.

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Intel and Pentium are registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries.

Other names and brands may be claimed as the property of others.

SFX12V Power Supply Design Guide

Version 2.3

Contents

1. Introduction ..........................................................................................................................6

1.1. Scope ...........................................................................................................................6

1.2. Changes for Version 2.3................................................................................................6

1.2.1. Efficiency ..........................................................................................................6

1.2.2. Increased Power ................................................................................................6

1.2.3. “PS3” form factor added......................................................................................7

1.2.4. External Fan Control - Optional............................................................................7

2. Applicable Documents.........................................................................................................8

3. Electrical..............................................................................................................................9

3.1. AC Input ........................................................................................................................9

3.1.1. Input Over-current Protection...............................................................................9

3.1.2. Inrush Current Limiting ........................................................................................9

3.1.3. Input Under Voltage ............................................................................................10

3.1.4. Regulatory.........................................................................................................10

3.1.5. Catastrophic Failure Protection............................................................................10

3.2. DC Output.....................................................................................................................10

3.2.1. DC Voltage Regulation........................................................................................10

3.2.2. Remote Sensing ................................................................................................11

3.2.3. Typical Power Distribution ...................................................................................12

3.2.4. Power Limit / Hazardous Energy Levels................................................................15

3.2.5. Efficiency ..........................................................................................................17

3.2.6. Output Ripple/Noise...........................................................................................19

3.2.7. Output Transient Response.................................................................................21

3.2.8. Capacitive Load..................................................................................................21

3.2.9. Closed-loop Stability...........................................................................................22

3.2.10. +5 VDC / +3.3 VDC Power Sequencing ..............................................................22

3.2.11. Voltage Hold-up Time........................................................................................22

3.3. Timing / Housekeeping / Control ......................................................................................22

3.3.1. PWR_OK..........................................................................................................23

3.3.2. PS_ON#............................................................................................................23

3.3.3. +5 VSB .............................................................................................................24

3.3.4. Power-on Time ...................................................................................................25

3.3.5. Rise Time ..........................................................................................................25

3.3.6. Overshoot at Turn-on / Turn-off.............................................................................25

3.3.7. Reset after Shutdown .........................................................................................25

3.3.8. +5 VSB at AC Power-down.................................................................................25

3.4. Output Protection...........................................................................................................26

3.4.1. Over Voltage Protection......................................................................................26

SFX12V Power Supply Design Guide Version 2.3

3.4.2. Short -circuit Protection.......................................................................................26

3.4.3. No-load Operation ..............................................................................................26

3.4.4. Over Current Protection.......................................................................................26

3.4.5. Over-Temperature Protection...............................................................................27

3.4.6. Output Bypass...................................................................................................27

4. Mechanical...........................................................................................................................27

4.1. Labeling / Marking..........................................................................................................27

4.2. Airflow / Fan..................................................................................................................28

4.3. AC Connector ................................................................................................................29

4.4. DC Connectors ..............................................................................................................29

4.4.1. SFX Main Power Connector.................................................................................30

4.4.2. Peripheral Connector(s)......................................................................................30

4.4.3. Floppy Drive Connector .......................................................................................30

4.4.4. +12 V Power Connector ......................................................................................31

4.4.5. Serial ATA Power Connector...............................................................................31

5. Environmental ......................................................................................................................32

5.1. Temperature..................................................................................................................32

5.2. Thermal Shock (Shipping) ...............................................................................................32

5.3. Humidity .......................................................................................................................32

5.4. Altitude.........................................................................................................................32

5.5. Mechanical Shock .........................................................................................................32

5.6. Random Vibration ..........................................................................................................33

5.7. Acoustics......................................................................................................................33

5.8. Ecological Requirements................................................................................................33

6. Electromagnetic Compatibility.............................................................................................34

6.1. Emissions.....................................................................................................................34

6.2. Immunity .........................................................................................................................34

6.3. Input Line Current Harmonic Content ................................................................................34

6.4. Magnetic Leakage Fields................................................................................................36

6.5. Reliability......................................................................................................................36

6.6. Voltage Fluctuations and Flicker .....................................................................................36

7. Safety ...................................................................................................................................37

7.1. North America...............................................................................................................37

7.2. International...................................................................................................................37

8. SYSTEM COOLING CONSIDERATIONS ..................................................................................38

APPENDIX A GUIDELINES FOR A LOWER PROFILE PACKAGE ................39

APPENDIX B GUIDELINES FOR A TOP MOUNT FAN PACKAGE................41

APPENDIX C GUIDELINES FOR A REDUCED DEPTH, TOP MOUNT FAN PACKAGE

APPENDIX D GUIDELINES FOR A LOWER PROFILE PACKAGE ................47

APPENDIX E GUIDELINES FOR PS3 FORM FACTOR ................................50

SFX12V Power Supply Design Guide

Version 2.3

Figures

Figure 1 Cross loading Graph for 160W configuration.......................................................................12

Figure 2 Cross loading Graph for 180W configuration.......................................................................13

Figure 3 Cross loading Graph for 220W configuration.......................................................................14

Figure 4 Cross loading Graph for 240W configuration.......................................................................15

Figure 5 Differential Noise Test Setup ............................................................................................19

Figure 6 Power Supply Timing ......................................................................................................22

Figure 7 PS_ON# Signal Characteristics .......................................................................................24

Figure 8 SFX12V Connectors ........................................................................................................29

Figure 9 Serial ATA connector.......................................................................................................31

Figure 10 40 mm Profile Mechanical Outline ..................................................................................40

Figure 11 Chassis Cutout.............................................................................................................40

Figure 12 Top Mount Fan Profile Mechanical Outline.......................................................................42

Figure 13 Chassis Cutout.............................................................................................................43

Figure 14 Recessed Fan Mounting ................................................................................................43

Figure 15 Reduced Depth Top Mount Fan Profile Mechanical Outline ...............................................45

Figure 16 Chassis cutout .............................................................................................................46

Figure 17 60 mm Mechanical Outline ............................................................................................48

Figure 18 Chassis Cutout.............................................................................................................49

Figure 19 PS3 Mechanical Outline................................................................................................51

Tables

Table 1: AC Input Line Requirements..............................................................................................9

Table 2: DC Output Voltage Regulation...........................................................................................10

Table 3: Typical Power Distribution for a 160 W SFX12V Configurations .............................................12

Table 4: Typical Power Distribution for 180 W SFX12V Configurations ...............................................13

Table 5: Typical Power Distribution for 220 W SFX12V Configurations ...............................................14

Table 6: Typical Power Distribut ion for 240 W SFX12V Configurations ...............................................15

Table 7: Efficiency Vs Load..........................................................................................................17

Table 8. Loading table for Efficiency measurements ........................................................................17

Table 9: Energy Star Input Power Consumption ..............................................................................18

Table 10: DC Output Noise/Ripple .................................................................................................19

Table 11: DC Output Transient Step Sizes.....................................................................................21

Table 12: Output Capacitive Loads ................................................................................................21

Table 13: PWR_OK Signal Characteristics ....................................................................................23

Table 14: PS_ON# Signal Characteristics ......................................................................................24

Table 15: Over Voltage Protection.................................................................................................26

Table 16: Harmonic Limits, Class D equipment .............................................................................36

SFX12V Power Supply Design Guide Version 2.3

1. Introduction

1.1. Scope

This document provides design suggestions for a family of small form factor power supplies that are primarily intended for use with microATX and FlexATX systems. The connectors conform to the basic requirements of the ATX main board specification except that -5 V is not available. It should not be inferred that all SFX power supplies must conform exactly to the content of this document. The design specifics described are not intended to support all possible systems, because power supply needs vary depending on system configuration.

1.2. Changes for Version 2.3

This section provides a brief summary of the changes to the SFX Power Supply Design Guide for Version 2.3.

1.2.1. Efficiency

This design guide includes updated guidance for standby efficiency. This version has increased max load efficiency to 70%, and added loading recommendations for normal and idle loading.

1.2.2. Increased Power

The trend for faster and more powerful systems results in an increasing need for higher rated power supplies. Additional power ratings have been added with increased 12 VDC current to meet the needs of present and future system needs. Wattages at 220 W and 240 W have been defined to meet the requirements of today’s and the next generation of high performance Intel Pentium® 4 processor-based systems. Recommendations for the 90W, 120 W, and 150 W versions have been removed. These recommendations are for guidance and are not intended to limit the choice of power ratings available. Loading table have been included to provide guidance for the loading on each voltage rail which can be used to determine if the minimum efficiency meet the recommendations. Included with the power recommendations are updated cross regulation graphs that show typical system power loading of 5V +3.3V rail vs. the 12V rail.

SFX12V Power Supply Design Guide

Version 2.3

1.2.3. “PS3” form factor added

The industry standard “PS3” form factor has been added to this document. It has identical electrical requirements as the typical SFX12V power supply with a case outline that resembles a shorten ed version of an ATX12V power supply. See appendix E for mechanical details.

1.2.4. External Fan Control - Optional

With the implementation of Suspend To RAM (STR or S3 sleep state), the system can obtain a low power condition without the need for external fan shutoff. In STR mode, the main outputs including 12 V are not available from the power supply and all system fans and the power supply fan will be off. FANC and FANM functions described in Version 1.1 have been removed for Version 2.0. Some vendors may still offer the external Fan functions as an option.

SFX12V Power Supply Design Guide Version 2.3

2. Applicable Documents

The latest revision in effect of the following documents forms a part of this document to the extent specified.

Document title Description

FCC Rules Part 15, Class B Title 47, Code of Federal Regulations, Part 15 ICES-003: 1997, Class B Interference-Causing Equipment Standard – Digital Apparatus EN 55022: 1998 + Amendment

A1:2000 Class B CISPR 22: 1997, Class B

AS/NZS 3548:1995, Class B

EN 55024:1998 IEC 60950, 3rd ed., 1999 Safety of Information Technology Equipment

Information Technology Equipment – Radio disturbance characteristics – Limits and methods of measurement

Information Technology Equipment – Immunity Characteristics – Limits and methods of measurement

EN 60950: 2000 Safety of Information Technology Equipment UL 60950, 3rd ed., 2000 Safety of Information Technology Equipment

CSA 22.2 No. 60950-00 Safety of Information Technology Equipment

SFX12V Power Supply Design Guide

Version 2.3

3. Electrical

The electrical requirements that follow are to be met over the environmental ranges specified in Section 5 unless otherwise noted.

3.1. AC Input

Table 1 lists AC input voltage and frequency requirements for continuous operation. The power supply shall be capable of supplying full-rated output power over two input voltage ranges rated 100-127 VAC and 200-240 VAC RMS nominal. The correct input range for use in a given environment may be either switch-selectable or auto-ranging. The power supply shall automatically recover from AC power loss. The power supply must be able to start up under peak loading at 90 VAC

Table 1: AC Input Line Requirements

Parameter Minimum Nominal* Maximum Unit

Vin (115 VAC) 90 115 135 VAC Vin (230 VAC) 180 230 265 VAC Vin Frequency 47 -- 63 Hz

*Note: Nominal voltages for test purposes are considered to be within ±1.0 V of nominal.

3.1.1. Input Over-current Protection

The power supply shall incorporate primary fusing for input over-current protection to prevent damage to the power supply and meet product safety requirements. Fuses should be slow-blow – type or equivalent to prevent nuisance trips1.

3.1.2. Inrush Current Limiting

Maximum inrush current from power-on (with power on at any point on the AC sine) and including, but not limited to, three line cycles, shall be limited to a level below the surge rating of the input line cord, AC switch if present, bridge rectifier, fuse, and EMI filter components. Repetitive

rms

. For Denmark and Switzerland international safety requirements, if the internal over -current protective devices exceed 8A for Denmark and 10A for Switzerland, then the power supply must pass international safety testing to EN 60950 using a maximum 16A over -current protected branch circuit, and this 16A (time delay fuse) branch circuit protector must not open during power supply abnormal operation (output short circuit and component fault) testing.

SFX12V Power Supply Design Guide Version 2.3

ON/OFF cycling of the AC input voltage should not damage the power supply or cause the input fuse to blow.

3.1.3. Input Under Voltage

The power supply shall contain protection circuitry such that the application of an input voltage below the minimum specified in Section 3.1, Table 1, shall not cause damage to the power supply.

3.1.4. Regulatory

At a minimum, both system and power supply typically must pass safety and EMC testing per the limits and methods described in the EN 55024 specification prior to sale in most parts of the world. Additional national requirements may apply depending on the design, product end use, target geography, customer, and other variables. Consult your company’s Product Safety and Regulations department for more details.

3.1.5. Catastrophic Failure Protection

Should a component failure occur, the power supply should not exhibit any of the following:

• Flame

• Excessive smoke

• Charred PCB

• Fused PCB conductor

• Startling noise

• Emission of molten material

• Earth ground fault (short circuit to ground or chassis enclosure)

3.2. DC Output

3.2.1. DC Voltage Regulation

The DC output voltages shall remain within the regulation ranges shown in Table 2 when measured at the load end of the output connectors under all line, load, and environmental conditions. The voltage regulation limits shall be maintained under continuous operation at any steady state temperature and operating conditions specified in Section 5. DC Output Voltage Regulation

Table 2: DC Output Voltage Regulation

Output Range Minimum Nominal Maximum Unit

+12 V DC (Note) ±5% +11.40 +12.00 +12.60 Volts +5 VDC ±5% +4.75 +5.00 +5.25 Volts +3.3 VDC ±5% +3.14 +3.30 +3.47 Volts

-12 V DC ±10% -10.80 -12.00 -13.20 Volts

SFX12V Power Supply Design Guide

Version 2.3

+5 VSB ±5% +4.75 +5.00 +5.25 Volts

Note: At +12 VDC peak loading, regulation at the +12 VDC output can go to ± 10%.

3.2.2. Remote Sensing

The +3.3 VDC output should have provisions for remote sensing to compensate for excessive cable drops. The default sense should be connected to pin 11 of the main power connector. The power supply should draw no more than 10 mA through the remote sense line to keep DC offset voltages to a minimum.

SFX12V Power Supply Design Guide

+ 3.3V rail)

Version 2.3

3.2.3. Typical Power Distribution

DC output power requirements and distributions will vary based on specific system options and implementation. Significant dependencies include the quantity and types of processors, memory, add-in card slots, and peripheral bays, as well as support for advanced graphics or other features. Tables 3 through 7 show the power distribution for power supplies in the range of 160 W to 240 W. Figure 2 through Figure 4 graphically shown the recommendations for cross regulation. It is ultimately the responsibility of the designer to define a power budget for a given target product and market.

Table 3: Typical Power Distribution for a 160 W SFX12V Configurations

Output Minimum

Current (amps)

+12 VDC 1.0 9.0 10.0

+5 VDC 0.3 12.0 (Note)

+3.3 VDC 0.5 16.7 (Note)

-12 VDC 0.0 0.3 +5 VSB 0.0 1.5 2.0

Note: Total combined output of 3.3 V and 5 V is < 61 W. Peak currents may last up to 17 seconds with not more than one occurrence per minute

Maximum Current (amps)

Peak Current (amps)

Figure 1 Cross loading Graph for 160W configuration

160W Cross Regulation

(5V rail + 3.3V rail vs. 12V)

70 60 50 40 30 20 10

5V + 3.3V power (watts)

0 50 100 150

12V power (watts)

Combined Power (5V rail

SFX12V Power Supply Design Guide

Version 2.3

Table 4: Typical Power Distribution for 180 W SFX12V Configurations

Output Minimum

Current (amps)

+12 VDC 1.0 13.0 15.0 +5 VDC 0.3 12.0 (Note) +3.3 VDC 0.5 16.7 (Note)

-12 VDC 0.0 0.3 +5 VSB 0.0 2.0 2.5

Note: Total combined output of 3.3 V and 5 V is < 63 W Peak currents may last up to 17 seconds with not more than one occurrence per minute

Maximum Current (amps)

Peak Current (amps)

Figure 2 Cross loading Graph for 180W configuration

180W Cross Regulation

(5V rail + 3.3V rail vs. 12V)

70 60 50 40 30 20 10

5V + 3.3V power (watts)

0 50 100 150 200

12V power (watts)

Combined Power (5V rail + 3.3V rail)

SFX12V Power Supply Design Guide Version 2.3

Table 5: Typical Power Distribution for 220 W SFX12V Configurations

Output Minimum

Current (amps)

+12 VDC 1.0 15.0 17.0 +5 VDC 0.3 13.0 (Note) +3.3 VDC 0.5 17.0 (Note)

-12 VDC 0.0 0.3 +5 VSB 0.0 2.0 2.5

Note: Total combined output of 3.3 V and 5 V is < 80 W Peak currents may last up to 17 seconds with not more than one occurrence per minute

Maximum Current (amps)

Peak Current (amps)

Figure 3 Cross loading Graph for 220W configuration

220W Cross Regulation

(5V rail + 3.3V rail vs. 12V)

80 70 60 50 40 30 20 10

5V + 3.3V power (watts)

0 50 100 150 200

12V power (watts)

Combined Power (5V rail + 3.3V rail)

SFX12V Power Supply Design Guide

Version 2.3

Table 6: Typical Power Distribution for 240 W SFX12V Configurations

Output Minimum

Current (amps)

+12 VDC 1.0 16.0 18.0 +5 VDC 0.3 19.0 (Note) +3.3 VDC 0.5 18.0 (Note)

-12 VDC 0.0 0.3 +5 VSB 0.0 2.0 2.5

Note: Total combined output of 3.3 V and 5 V is < 105 W Peak currents may last up to 17 seconds with not more than one occurrence per minute

Maximum Current (amps)

Peak Current (amps)

Figure 4 Cross loading Graph for 240W configuration

120

100

240W Cross Regulation

(5V rail + 3.3V rail vs. 12V)

Combined Power (5V rail + 3.3V rail)

5V + 3.3V power (watts)

0 50 100 150 200 250

12V power (watts)

3.2.4. Power Limit / Hazardous Energy Levels

Under normal or overload conditions, no output shall continuously provide 240 VA under any conditions of load including output short circuit, per the requirement of UL 1950/CSA 950 / EN 60950/IEC 950.

SFX12V Power Supply Design Guide Version 2.3

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Enhance SFX12V Version 2.3 Power Supply Design Guide

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