PCI Express M.2 Specification
November 5, 2020
PCI Express M.2 Specification | 16
Revision 4.0, Version 1.0
Figure 2-66. H3.2-D1 - Stack-up Top Mount Double-sided Add-in Card for 1.20 Maximum Top-side
Component Height ................................................................................................................. 91
Figure 2-67. H3.2-D2 - Stack-up Top Mount Double-sided Add-in Card for 1.35 Maximum Top-side
Component Height ................................................................................................................. 91
Figure 2-68. H3.2-D3 - Stack-up Top Mount Double-sided Add-in Card for 1.5 Maximum Top-side
Component Height ................................................................................................................. 92
Figure 2-69. H4.2-D5 - Stack-up Top Mount Double-sided Add-in Card for 1.5 Maximum Top-side
Component Height with 1.5 Maximum Bottom-side Component Height .............................. 92
Figure 2-70. H4.2-D8-P Stack-up Top Mount Double-sided Add-in Card for 3.2mm +0 / -0.5 Top-side
dimension and 1.5 Maximum Bottom-side Component Height ............................................. 92
Figure 2-71. Example of Top Mount Motherboard Land Pattern - Key B Shown ....................................... 93
Figure 2-72. Mid-mount (In-line) Connector Dimensions ........................................................................... 94
Figure 2-73. Mid-mount (In-line) System Length ........................................................................................ 95
Figure 2-74. Stack-up Mid-mount (In-line) Single-sided (S1) Add-in Card for 1.2 Maximum
Component Height ................................................................................................................. 96
Figure 2-75. Stack-up Mid-mount (In-line) Single-sided (S2) Add-in Card for 1.35 Maximum
Component Height ................................................................................................................. 96
Figure 2-76. Stack-up Mid-mount (In-line) Single-sided (S3) Add-in Card for 1.5 Maximum
Component Height ................................................................................................................. 96
Figure 2-77. Stack-up Mid-mount (In-line) Double-sided (D1) Add-in Card for 1.2 Maximum
Top-side Component Height .................................................................................................. 97
Figure 2-78. Stack-up Mid-mount (In-line) Double-sided (D2) Add-in Card for 1.35 Maximum
Top-side Component Height .................................................................................................. 97
Figure 2-79. Stack-up Mid-mount (In-line) Double-sided (D3) Add-in Card for 1.5 Maximum
Top-side Component Height .................................................................................................. 97
Figure 2-80. Stack-up Mid-mount (In-line) Double-sided (D4) Add-in Card for 1.5 Maximum
Top-side Component Height .................................................................................................. 98
Figure 2-81. Stack-up Mid-mount (In-line) Double-sided (D5) Add-in Card for 1.5 Maximum
Top-side and Bottom-side Component Height ....................................................................... 98
Figure 2-82. Example of Mid-mount Motherboard Land Pattern Diagram – Key B Shown ....................... 99
Figure 2-83. Connector Key ..................................................................................................................... 100
Figure 2-84. M.2 Connector Keying Diagram ........................................................................................... 101
Figure 2-85. Dual Add-in Card Key Scheme Example ............................................................................. 102
Figure 2-86. Mid-mount Add-in Card Mounting Interface ......................................................................... 103
Figure 2-87. Single-sided Top Mount Solder-down Stand-off .................................................................. 104
Figure 2-88. Elevated Single-sided Top Mount Solder Stand-off ............................................................. 104
Figure 2-89. Low Profile Double-sided Top Mount Solder-down Stand-off .............................................. 105
Figure 2-90. Double-sided Top Mount Solder-down Stand-off ................................................................. 105
Figure 2-91. Elevated Double-sided Top Mount Solder-down Stand-off ................................................. 105
Figure 2-92. Flat Stand-off ........................................................................................................................ 106
Figure 2-93. Shouldered Stand-off ........................................................................................................... 107
Figure 2-94. Screw Guidelines ................................................................................................................. 107