What size is a half brick converter?

What size is a half brick converter?

In the world of power electronics, where space on a printed circuit board is both precious and expensive, an entire language has sprung up around packaging. Engineers don’t just talk about watts and volts; they talk about bricks. A “full brick” module. A “quarter brick.” And, most commonly in dense telecom and industrial systems, a “half brick.” If you’re laying out a board or sourcing a DC-DC converter for a project, knowing exactly what that term means—down to the millimeter—is essential. The name isn’t just a casual descriptor; it’s a specific, industry-standard footprint that ensures interchangeability between manufacturers.

So, what size is a half brick converter? The short answer: 2.28 inches wide by 2.4 inches long, with a height that typically hovers around 0.5 inches. In metric, that’s approximately 57.9 mm by 61.0 mm, with a height of 12.7 mm. But those numbers only tell part of the story. The half brick is a carefully defined form factor with standard pinouts, mounting hole locations, and thermal considerations that make it a quiet workhorse in the power supply architecture of everything from server racks to railway electronics.

**The Origin: Brick Sizes as a Standard**

The “brick” terminology emerged in the 1990s when the power supply industry, driven by the needs of telecommunications and networking equipment, began standardizing the physical size of board-mounted DC-DC converters. Before these standards, every manufacturer had their own footprint, which made second-sourcing a nightmare and board redesigns a constant headache. The Distributed-power Open Standards Alliance (DOSA) and other industry bodies eventually coalesced around a family of sizes that are still in use today.

The original standard was the full brick, a chunky module measuring roughly 4.6 inches long by 2.4 inches wide. It could handle hundreds of watts but consumed a huge swath of board real estate. As power density improved, the industry cut that full brick exactly in half, creating the half brick. The length was chopped from 4.6 inches down to 2.4 inches, while the width remained fixed at 2.28 inches. It was a brilliant move: you could now fit two converters in the same rectangular footprint as one full brick, doubling power per square inch without changing the board’s mounting geometry significantly. The half brick, in turn, was halved again to create the quarter brick, which measures roughly 2.3 by 1.45 inches.

**The Exact Dimensions and Tolerances**

A half brick’s footprint is standardized by the DOSA consortium and matched by major manufacturers like Vicor, TDK-Lambda, Artesyn, and Murata. The board-level dimensions are:

- Length: 2.40 inches (60.96 mm), often rounded to 61.0 mm in datasheets.

- Width: 2.28 inches (57.91 mm), typically given as 57.9 mm.

- Height: The seated height above the board is usually 0.50 inches (12.7 mm) for the baseplate version, which is the most common configuration. Modules without a baseplate (open-frame) can be slightly shorter, sometimes 0.43 inches (11.0 mm), but the 0.5-inch profile with an aluminum thermal baseplate is the benchmark.

The mounting holes are situated at the four corners of the module, spaced to match a 1.90-inch by 2.00-inch bolt pattern, allowing the converter to be securely screwed to a heat sink or cold plate through the baseplate. The pinout is also standardized: typically six pins for the power and control interface, although half bricks can have more pins depending on features like remote sense, trim, and enable. The standard pin length allows for both through-hole soldering and press-fit mounting.

In metric terms, which are more common on modern datasheets, you’ll see 61.0 x 57.9 x 12.7 mm as the canonical half brick size. The tolerance on the length and width is typically ±0.5 mm, and the height tolerance is ±1.0 mm, though exact numbers vary slightly by vendor.

**How Much Power Can You Pack Into That Space?**

The half brick’s physical size is directly tied to its thermal capability. With a baseplate firmly attached to a heat sink, a typical half brick converter can handle anywhere from 150 to 400 watts of output power, with some high-efficiency designs touching 600 watts. The actual power depends on the input and output voltages, the conversion topology, and the ambient temperature and airflow. For instance, a 48V-input, 12V-output half brick might be rated for 300W at 50°C with 400 LFM of forced air cooling. Advanced resonant topologies and gallium nitride (GaN) power transistors are pushing these numbers higher, squeezing more power from the same unchanged footprint.

This power-to-size sweet spot is exactly why the half brick has endured. It’s large enough to house the magnetics and switching devices needed for substantial DC-DC conversion, yet small enough that you can place multiple converters on a single board to generate multiple voltage rails.

**Half Brick vs. Other Brick Sizes**

To fully appreciate the half brick, it helps to see it alongside its family:

- Full brick: 4.6 x 2.4 x 0.5 inches (116.8 x 61.0 x 12.7 mm). Twice the length of a half brick, typically 400W to 1000W.

- Half brick: 2.4 x 2.28 x 0.5 inches (61.0 x 57.9 x 12.7 mm). 150W to 400W.

- Quarter brick: 2.3 x 1.45 x 0.5 inches (58.4 x 36.8 x 12.7 mm). 50W to 150W.

- Eighth brick: Even smaller, around 2.3 x 0.9 inches, handling up to about 75W.

The half brick sits right at the heart of the power-density curve, offering enough thermal management to handle serious loads without gobbling up the excessive space of a full brick. It’s the most popular brick size for intermediate bus converters that step down a 48V rail to 12V or 5V on densely packed boards.

**Where You’ll Find Half Brick Converters**

The half brick isn’t a consumer-facing component. It lives deep inside infrastructure. You’ll spot them mounted on power distribution boards in telecom base stations, on server motherboards within data center racks, in medical imaging systems, in industrial drives, and in aircraft avionics. Anywhere that demands a reliable, isolated DC-DC conversion with a standard footprint that can be sourced from multiple vendors, the half brick thrives. The standardization means a hardware designer can lay out a board and qualify two or three different manufacturers’ half bricks, guaranteeing supply chain resilience.

**Why the Size Still Matters**

In an era where power supplies are shrinking everywhere, the half brick’s dimensions remain remarkably stable. The standard hasn’t changed significantly in two decades because changing it would break compatibility with millions of existing designs. Instead, innovation has moved inside the package — better semiconductors, planar magnetics, and higher switching frequencies all pack more power into the exact same 61.0 x 57.9 mm rectangle. The half brick size is a physical constant in an industry of rapid change, a testament to a well-designed standard that struck the right balance between space and thermal performance.

So when you ask what size a half brick converter is, you’re not just asking for a measurement. You’re identifying a specific, proven building block of modern power electronics. The dimensions — 2.4 inches long by 2.28 inches wide by half an inch tall — are only the beginning. Behind them lies an entire ecosystem of standardized performance, thermal design, and cross-vendor compatibility that has quietly powered the infrastructure of the digital world for more than twenty years.