Electronic Design

A Plethora Of Board Form Factors Gives Designers A Range Of Options

Designing a new system from scratch? You can probably find a board form factor that can speed delivery time with expansion and enhancement options that a custom solution would lack.

Board-level products are commonly used in a range of embedded systems, including rugged applications such as avionics and military (“Military And Avionics Applications Demand Rugged Hardware”). In these cases, 3U and 6U boards plug into a backplane.

Tek Microsystems’ QuiXilica Titan-V5 VXS board offers four 1-Gsample/s, 12-bit analog-to-digital converters (ADCs) and four 1.2-Gsample/s, 14-bit digital-toanalog converter (DAC) channels (Fig. 1). Its three Virtex-5 FPGAs handle these interfaces, and the VXS support blends the parallel VME bus with high-speed serial fabrics such as Serial RapidIO.

The size of the boards and the application areas lend themselves to expansion via mezzanine cards. IEEE P1381.1 PMC (PCI mezzanine card), VITA 42 XMC (switched mezzanine card), and VITA 57 FMC (FPGA mezzanine card) are three common standards.

Pentek’s 7800 series of high-performance I/O boards is based on a common PC half-length x8 PCI Express (PCIe) 2.0 carrier board (Fig. 2). The carrier board hosts a single PMC/XMC module versus the normal 3U or 6U home that’s associated with board standards such as VME, VXS, VPX, CompactPCI, and Compact- PCI Express.

Pentek already supplies PMC and XMC cards for the Pentek 7800, so this is simply an expansion to a PC form factor. A PC carrier board can be used for development, but it also opens up development platforms that can utilize the same mezzanine cards that might be deployed using the 3U or 6U boards.


Board form factors don’t have to follow a set standard. Some follow form factors associated with other components.

Advanced Digital Logic’s ADL945HD follows the 3.5-in. hard-disk form factor (146 by 102 mm). The 2.16-GHz dual-core Core 2 Duo is on the bottom of the board, so a case can be used as a heatsink (Fig. 3). The board also has serial advanced technology attachment (SATA) and enhanced integrated drive electronics (EIDE) interfaces for the matching hard drive.

Pentek had a great idea with its 7800 carrier board, but it needs a processor board like Adlink Technology’s NuPRO-730 PICMG 1.0 full-size single-board computer (SBC). The NuPRO-730 plugs into a PC backplane and brings out peripheral interfaces such as SATA and USB via additional edge connectors (Fig. 4).

Advantech’s ARK-6310-3M04E 1.6- GHz Atom-based system utilizes a Mini- ITX motherboard with dual Gigabit Ethernet ports, four USB ports, three serial ports, and one VGA port (Fig. 5). Mini-ITX has a single PCI slot for expansion. The fanless case has sufficient space for a 2.5-in. hard drive. It also has an optional Wi-Fi module and Video Electronics Standard Association (VESA) mounting bracket, and it requires 12 V to 24 V dc.


Lippert’s Cool SpaceRunner-LX800 is representative of the PC/104-Plus stacking approach (Fig. 6). The SBC has an AMD LX800 Geode processor, 256 Mbytes of RAM, and a 2-Gbyte solid-state disk. ISA and PCI bus connectors allow the stacking of peripheral boards as needed. The PC/104 Consortium and the Small Form Factor SIG have standards that add PCI Express support to this form factor.







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