Modular MicroTCA - Bringing Flexibility to MicroTCA Systems Design Flexibility There are two key solutions to having design flexibility in MicroTCA systems: cabinet-level and chassis-level modularity. Let’s look at cabinet-level first. MicroTCA can come in a wide number of configurations, including single (75 mm high) or double (150 mm high) modules; and compact, full, or mid-size widths. Further, pico, cube, or subrack chassis formats are all possibilities. See Diagram 1 for various backplane and chassis configurations. From a cabinet-level perspective, a different approach is possible. As opposed to loading enclosed chassis with 5 of the 6 sides enclosed (only front open for loading cards), imagine using open card cages without any top, bottom, side, or back covers. The backplane would be mounted to the back of the card cage. As the power and MicroTCA Carrier Hub (MCH) plug directly into the backplane, there is not a need for wiring, special mounting, etc. The open card cages would be accompanied by fan trays and heat exchangers for cooling in a stacked arrangement inside the cabinet. Without top or bottom covers, the open card cages allow air to flow through multiple stacks of MicroTCA shelves. Various implementations of card cage shelves, fans, and cooling units can be configured in the cabinet. For example, three 4U card cages with 14-slot backplanes can be stacked on top of each other with a fan tray blowing air underneath them. The heat exchanger plumbing would be on the inner sides of the cabinet and not take up rack space. This type of format maximizes space, but also allows a tremendous amount of flexibility in configurations. As the card cages are modular-based extrusions, it is easy to cut them in various lengths to mix-and-match module sizes and number of cards used. This MicroTCA closed-loop heat exchanger concept (designed according to ETSI 300-119-3) can dissipate approximately 6kW. The typical shelf temperature rise is 15C while the heat exchangers are able to provide a temperature drop of approximately 15C. Modular Shelves MicroTCA was created as a stamped sheet metal solution, but what about new product development and prototyping? MicroTCA shelf enclosures can come in a modular format with extrusions and modular card guides. Extrusions are aluminum strips with holes cut at regular intervals to accept card guides in whatever location the design requires. They can be easily cut in different lengths for various size and configuration requirements - without the need of expensive retooling. Therefore, the enclosure can accept backplanes in various slot sizes and pitches with little additional effort. With modular plastic card guides, the slots can be set at various pitches (distance between each slot), so configuring to the spacing from compact, to mid, to full size spacing is simple. Modular MicroTCA also allows single and double modules to be used in the same chassis or two sets of single modules to be stacked on one another. Overall, a modular design for MicroTCA creates a wealth of possibilities. Your design team resources will be saved, you won’t be customizing every little hardware component, and your product will go to market faster. Modular MicroTCA adds flexibility without the cost, time, and expense of starting from scratch. Walter Schindler
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