PCI Express Card Electromechanical Specification
PCI Express Card Electromechanical Specification
June 9, 2021
Revision 5.0, Version 1.0 5
Contents
MAY 27, 2021 ............................................................................................................................. 1
1. INTRODUCTION ................................................................................................................. 14
1.1. Terms and Definitions ................................................................................................. 16
1.2. Reference Documents ................................................................................................ 18
1.3. Specification Contents ................................................................................................ 19
1.4. Objectives .................................................................................................................. 19
1.5. Electrical Overview ..................................................................................................... 20
1.6. Mechanical Overview ................................................................................................. 21
1.7. 150 W Overview ......................................................................................................... 23
1.8. 225 W and 300 W Add-in Card Overview ................................................................... 24
1.9. 600 W Add-in Card Overview ..................................................................................... 25
2. AUXILIARY SIGNALS ........................................................................................................ 26
2.1. Reference Clock ......................................................................................................... 27
Low Voltage Swing, Differential Clocks........................................................................ 27
Spread Spectrum Clocking (SSC) ............................................................................... 28
Clock Architecture Requirements ................................................................................ 28
REFCLK AC Specifications ......................................................................................... 29
REF CLK Phase Jitter Specification ............................................................................ 30
REFCLK Phase Jitter Specification for 32.0 GT/s Systems .......................................... 31
2.2. PERST# Signal .......................................................................................................... 31
Initial Power Up (G3 to S0) .......................................................................................... 31
Power Management States (S0 to S3/S4 to S0) .......................................................... 32
Power Down ............................................................................................................... 33
2.3. WAKE# Signal ............................................................................................................ 35
2.4. SMBus (Optional) ....................................................................................................... 38
Capacitive Load of High-power SMBus Lines .............................................................. 39
Minimum Current Sinking Requirements for SMBus Devices ....................................... 39
SMBus “Back Powering” Considerations ..................................................................... 39
Power-on Reset .......................................................................................................... 39
2.5. JTAG Pins (Optional) .................................................................................................. 40
2.6. PWRBRK# Signal (Optional) ...................................................................................... 41
2.7. MFG Signal (Optional) ................................................................................................ 41
2.8. CLKREQ# Signal (Optional) ....................................................................................... 42
Power-up Requirements.............................................................................................. 43
Dynamic Clock Control ................................................................................................ 43
2.9. Auxiliary Signal Parameter Specifications ................................................................... 45
DC Specifications........................................................................................................ 45
AC Specifications ........................................................................................................ 46
3. HOT INSERTION AND HOT REMOVAL ............................................................................ 48
3.1. Scope ......................................................................................................................... 48
3.2. Presence Detect ......................................................................................................... 48
4. ELECTRICAL REQUIREMENTS ........................................................................................ 52
4.1. Power Supply Requirements ...................................................................................... 52
4.2. Power Consumption ................................................................................................... 55
4.3. Power Budgeting Capability ........................................................................................ 56
4.4. Power Supply Sequencing.......................................................................................... 56
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