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The proliferation of unmanned military vehicles tasked with critical communications and radar requirements drives the need for powerful data acquisition and signal processing products that must fit into increasingly tighter spaces. New industry standards meeting these needs offer smaller circuit boards and enclosures, optical gigabit serial links, and advanced thermal management strategies. With new resources found in the latest processors and FPGAs, system designers can now create powerful, compact systems surpassing performance levels achievable only a few years ago.

Emerging Small Form Factor Industry Standards

Figure 1. VITA 59 Rugged COM Express module adds thermal tabs to the sides of COM Express boards to pull heat out to a rugged aluminum frame. (Image courtesy MEN Micro)
The VITA and PICMG organizations actively promote and maintain standards for embedded systems suitable for commercial and military applications. Consisting of interested members from industry, academic and government organizations, each working group contributes towards the development of a new standard.

Once adopted and put into practice, refinements, and extensions to these standards ensure the long life cycle support required for most government programs. Customer acceptance of a new standard fosters an open community of vendors offering compatible products compliant with the standards. Competitive market forces help keep costs down, encouraging customers to request new systems based on successful standards.

Five new small form factor standards for embedded system modules and backplanes are currently in draft or trial use status awaiting final adoption. While each of these standards offers unique mechanical features, all of them are derivatives of existing embedded system standards. They all combine the most appropriate aspects of proven designs and leverage new technology to help reduce size, weight, power and cost (SWaP-C).

VITA 59 – Rugged COM Express

Figure 2. Rugged MicroTCA module incorporating an AMC module in a conduction-cooled enclosure suitable for harsh environments. (Image courtesy VadaTech)
The PICMG COM Express standard defines a series of modules (cards) and backplanes supporting processors, memory, networks, and specialized I/O. VITA 59 extends COM Express for use in harsh environments of extended temperature, shock and vibration. As shown in Figure 1, this is accomplished through relatively simple mechanical modifications to the printed circuit board of the module, leaving the central PCB design largely intact.

This strategy allows developers to create two similar versions of each module, one for commercial, and one for rugged applications. Software and firmware can be developed on the commercial platform and then later deployed without changes in a fully ruggedized system.

VITA 73 – Rugged Small Form Factor

Based on the electrical specifications of VPX (VITA 46 and 48), VITA 73 aims to shrink the modules and chassis as much as possible, while maintaining full system-level performance in rugged environments. Definitions for single- and double-wide modules, both 101.5 mm deep and 71 mm across, include a variety of backplane pin configurations supporting various module functions. These include power supplies, CPUs, 2.5 inch disk drives, and payload functions such as digital and analog I/O. The backplane uses different types of pin/socket connectors for power, SATA, analog I/O, and data. Gigabit serial data pins are rated to 10 Gb/sec to handle the latest versions of popular serial standards.

VITA 74 – System Small Form Factor Module

Like the VITA 73 specification, VITA 74 embraces all of the VITA 46 VPX electrical signal definitions for two sizes of small form-factor modules. Both are 89 mm deep and 75 mm across, with a width of either 12.68 or 19 mm. The modules connect to the backplane using the same connectors defined in VITA 57 for FMC modules and carriers, with 200 or 400 contacts, depending on the module width. Unlike VITA 73, these same connectors handle all power and signal connections to the modules.

The gigabit serial pins support rates up to at least 8 Gb/sec to support PCIe Gen 3 interfaces commonly found in embedded platforms. VITA 74 defines a comprehensive IPMI (intelligent platform management interface) using the I2C management bus that maintains and monitors system components and the identities of FRUs (field replaceable units).