COM Express® Overview

comThe COM Express® specification defines a family of Small Form Untitled-7-348x232Factor (SFF) and Computer On Module (COM) single board computers appropriate for a wide range of commercial and mil/aero applications. It is designed for the latest chip sets and serial signaling protocols, including PCI Express Gen 3, 10GbE, SATA, USB 3.0, and high resolution video interfaces.

COM Express not only provides the highest performance of the many small form factor standards and products available; it is unique in that it may be used in two ways:

(1) As a standalone single board computer; and
(2) As a processor mezzanine that can be plugged onto a base board, or “carrier” board, that contains the user’s application specific I/O.

The ability to plug a COM Express module onto a carrier board reduces the time and cost to develop a product, as the user does not need to understand the often complex details associated with high speed signaling or the latest chip sets. The customers’ product lifetime is increased as newer COM Express modules can simply be plugged onto the carrier board to improve performance or lower cost as they become available. This “future proofing” is unique to COM Express in the SFF marketplace.

Revision 3.0 of COM Express provides for the addition of up to four 10 Gigabit Ethernet (10GbE) interfaces on the board.   This new Type 7 connector version of COM Express also increases the number of PCI Express lanes to 32, providing a wealth of connectivity and interface options including the ability to facilitate the use of GPGPUs.

Because SFF applications often need to strike a careful balance between cost and performance, a variety of COM Express form factors and board sizes are defined in the standard.

Key Benefits and Features

  • High performance with high speed serial interfaces, including PCI Express Gen 3, 10GbE, USB 3.0, SATA, LVDS, CAN, HDMI, and other high res graphics.
  • Can be used standalone or in conjunction with a user-supplied carrier board that provides application specific I/O.
  • When used with a carrier board, performance upgrades can be as simple as plugging in the latest commercially available module with the newest chip sets.
  • 7 different versions are defined that balance cost, features, and performance while maintaining common connectors and mounting holes and common signaling where appropriate.

Family of Specifications

COM Express®
PICMG# Name Current Revision Date Description

COM Express®

Rev 3.0 2017-03-31

Defines a family of small form factor single board computers

COM Express Design Guide
PICMG# Name Current Revision Date Description

COM Express Design Guide

Rev 2.0 2013-12-06

Defines interfaces and requirements for Carrier boards


Errata 001 for PICMG COM.0 Revision 2
PICMG# Name Current Revision Date Description
COM.0 Errata

Errata 001 for PICMG COM.0 Revision 2

001 October 19, 2010
COM Express Carrier Design Guide Errata Notification
PICMG# Name Current Revision Date Description

COM Express Carrier Design Guide Errata Notification

R2 Errata 001 January 30, 2014

Target Applications

  • General purpose embedded computing, including industrial control, transportation, data acquisition, medical, point of sale, man machine interface, digital signage, multimedia and communications.
  • Ruggedized and high temperature range products are available for demanding applications, including mil/aero, rail, vehicular, and remote data acquisition.
  • High speed and connectivity applications using up to 32 PCIe Express lanes and up to quad 10GbE interfaces. Includes high bandwidth applications such as data centers and video surveillance. 

System Requirements