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Intel ATX
Power Supply Design Guide
Version 0.9
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Intel ATX Power Supply Design Guide Version 0.9 IMPORTANT INFORMATION AND DISCLAIMERS 1. INTEL CORPORATION (AND ANY CONTRIBUTOR) MAKES NO WARRANTIES WITH REGARD TO THIS DOCUMENT AND IN PARTICULAR DOES NOT WARRANT OR REPRESENT THAT THIS DOCUMENT OR ANY PRODUCTS MADE IN CONFORMANCE WITH IT WILL WORK IN THE INTENDED MANNER. NOR DOES INTEL (OR ANY CONTRIBUTOR) ASSUME RESPONSIBILITY FOR ANY ERRORS THAT THE DOCUMENT MAY CONTAIN OR HAVE ANY LIABILITIES OR OBLIGATIONS FOR DAMAGES INCLUDING, BUT NOT LIMI
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Intel ATX Power Supply Design Guide Version 0.9 Contents 1. Scope.................................................................................................................. 6 2. Applicable Documents ...................................................................................... 7 3. Electrical Specification ..................................................................................... 8 3.1 AC Input Requirements ...............................................................
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Intel ATX Power Supply Design Guide Version 0.9 4.4 AC Connector ........................................................................................................................23 4.5 DC Connectors ......................................................................................................................23 4.5.1 ATX Main Power Connector .....................................................................................24 4.5.2 Auxiliary Power Connector (for 250 W and 300 W C
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Intel ATX Power Supply Design Guide Version 0.9 Figures Figure 1: Power Supply Timing .............................................................................................................16 Figure 2: Power Supply Dimensions for Chassis in Which the P/S Does Not Cool Processor ............21 Figure 3: Power Supply Dimensions for Chassis in Which the P/S Cools the Processor.....................22 Figure 4: ATX Power Supply Connectors ....................................................
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Intel ATX Power Supply Design Guide Version 0.9 1. Scope This document outlines a reference ATX power supply that complies with the ATX Specification, Version 2.02 for motherboards and chassis. It is intended to provide additional power supply design information not detailed in the ATX 2.02 specification, including information about the physical form factor of the power supply, cooling requirements, connector configuration, and pertinent electrical and signal timing specifications. This documen
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Intel ATX Power Supply Design Guide Version 0.9 2. Applicable Documents The latest revision in effect of the following documents forms a part of this document to the extent specified. AB13-94-146 EACEM European Association of Consumer Electronics Manufacturers. Hazardous Substance List / Certification. ANSI C62.41-1991 IEEE Recommended Practice on Surge Voltages in Low-Voltage AC Circuits. ANSI C62.45-1992 IEEE Guide on Surge Testing for Equipment Connected to Low-Voltage AC Power Circuits. MIL-
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Intel ATX Power Supply Design Guide Version 0.9 3. Electrical Specification The electrical requirements that follow are to be met over the environmental ranges specified in Section 5 unless otherwise noted. 3.1 AC Input Requirements 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 sup
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Intel ATX Power Supply Design Guide Version 0.9 3.1.4 Immunity 3.1.4.1 Slow Transients The DC output(s) shall not exceed the limits specified in Section 3.2.1 as a result of the input power line noise defined in Table 2 under any load condition per EN 61000-4-11. Table 2: AC Line Voltage Transient Limits Duration Sag / Operating AC Voltage Line Performance Criteria Surge Frequency 0 to 500 ms 10% Rated AC voltages 50/60 Hz No loss of function or performance 0 to 15 15% Mid-point of rated AC 50/
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Intel ATX Power Supply Design Guide Version 0.9 3.1.4.2.3 Ring Wave, ANSI C62.45-1992 The crest value of the first half peak of the injected oscillatory wave will be 3.0 kV open circuit, with 200 and 500 A short circuit currents for the common and the normal modes of transient surge injection, respectively. No unsafe operation is allowed under any condition. No user-noticeable performance degradation for 1 kV Differential Mode (DM) or 2 kV Common Mode (CM) is allowed. Automatic or manual recov
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Intel ATX Power Supply Design Guide Version 0.9 3.1.5 Catastrophic Failure Protection The primary circuit design and the components specified in the same should be such that, 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. 3.2 DC Output Requirements 3.2.1 DC Voltage Regulation The DC output voltages shall remain within the regulation ranges shown in Table 3 when measured a
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Intel ATX Power Supply Design Guide Version 0.9 3.3 Typical Power Distribution Although power requirements and distributions will depend on the specific system options and implementation, this section identifies several potential configurations. For a single processor mini-tower configuration with one ISA slot, three PCI slots, one shared slot, and six peripheral bays, a minimum 160 W sustained (200 W peak) power supply should be sufficient for a typical application. For a full tower, dual pro
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Intel ATX Power Supply Design Guide Version 0.9 Table 6: Typical Power Distribution for a 250 W Configuration Min. Max. Peak Notes: Current Current Current Requires the 1x6 auxiliary power connector to carry Output (amps) (amps) (amps) the 3.3 V & 5 V currents to the PCB. +12VDC 0.0 10.0 12.0 +5VDC 1.0 25.0 +3.3VDC and +5VDC combined power 145 W Max +3.3VDC 0.3 16.0 Pin 11 default +3.3 V sense required -5VDC 0.0 0.3 -12VDC 0.0 0.8 +5VSB 0.0 0.72 See Section 3.4.3. Table 7: Typical Power Distri
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Intel ATX Power Supply Design Guide Version 0.9 3.3.3 Output Ripple/Noise The following output ripple/noise requirements should be met throughout the load ranges specified in Section 3.3, and under all input voltage conditions as specified in Section 3.1. Ripple and noise are defined as periodic or random signals over a frequency band of 10 Hz to 20 MHz. Measurements shall be made with an oscilloscope with 20 MHz bandwidth. Outputs should be bypassed at the connector with a 0.1 μF ceramic disk
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Intel ATX Power Supply Design Guide Version 0.9 3.3.7 +5VDC/+3.3VDC Power Sequencing The +5VDC output level must be equal to or greater than the +3.3VDC output at all times during power-up and normal operation. The time between the +5VDC output reaching its minimum in-regulation level and +3.3VDC reaching its minimum in-regulation level must be less than or equal to 20 ms. 3.3.8 Voltage Hold-up Time The power supply shall maintain output regulation per Section 3.2.1 despite a loss of input powe
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Intel ATX Power Supply Design Guide Version 0.9 3.4 Timing / Housekeeping / Control Off PS_ON# ~ On ~ 95% +5VDC/+3.3VDC O/P 10% T5 ~ PWR_OK T3 T4 T2 PWR_OK Sense Level = 95% of nominal Figure 1: Power Supply Timing Notes: T is defined in Section 3.4.5. 2 T , T , and T are defined in Table 9. 3 4 5 3.4.1 PWR_OK PWR_OK is a “power good” signal. It should be asserted high by the power supply to indicate that the +5VDC and +3.3VDC outputs are above the undervoltage thresholds listed in Section 3.2
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Intel ATX Power Supply Design Guide Version 0.9 3.4.2 PS_ON# PS_ON# is an active-low, TTL-compatible signal that allows a motherboard to remotely control the power supply in conjunction with features such as soft on/off, wake-on-LAN, or wake-on-modem. When PS_ON# is pulled to TTL low, the power supply should turn on the five main DC output rails: +12VDC, +5VDC, +3.3VDC, -5VDC, and -12VDC. When PS_ON# is pulled to TTL high or open circuited, the DC output rails should not deliver current and sh
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Intel ATX Power Supply Design Guide Version 0.9 3.4.5 Risetime The output voltages shall rise from <10% of nominal to within the regulation ranges specified in Section 3.2.1 within 0.1 ms to 20 ms (0.1 ms ≤ T ≤ 20 ms). 2 3.4.6 Overshoot at Turn-on/Turn-off The output voltage overshoot upon the application or removal of the input voltage, or the assertion/deassertion of PS_ON#, under the conditions specified in Section 3.1, shall be less than 10% above the nominal voltage. There must be a smooth
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Intel ATX Power Supply Design Guide Version 0.9 3.5 Output Protection 3.5.1 Overvoltage Protection The overvoltage sense circuitry and reference shall reside in packages that are separate and distinct from the regulator control circuitry and reference. No single point fault shall be able to cause a sustained overvoltage condition on any or all outputs. The supply shall provide latch-mode overvoltage protection as defined below. Table 11: Overvoltage Protection Output Min. Nom. Max. Unit +12VD
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Intel ATX Power Supply Design Guide Version 0.9 4. Mechanical Requirements 4.1 Labeling / Marking Each supply shall be marked with the following, at minimum: • Access warning text (“Do not remove this cover. Trained service personnel only. No user serviceable components inside.”) in English, German, Spanish, French, Chinese, and Japanese with universal warning markings. • Manufacturer information: manufacturer's name, part number, and lot date code in human-readable text format, etc. • Nominal
