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Features
Applications
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Features
Applications
Click here for a datasheet.
Features
Click here for a datasheet.
Features
Applications
Click here for a datasheet.
Features
Click here for a datasheet.
Taiwan Semiconductor Co., Ltd., a global manufacturer of discrete devices (diodes, MOSFETs) and power management ICs, introduces a new series of 45V and 60V Trench Schottky rectifiers in SMPC4.6U package and AEC-Q101 qualified. Samples and products are in stock and available.
The TSUPxM45SH & TSUPxM60SH Schottky rectifiers with a Tj max 175°C offer low leakage current and low forward voltage drop. The series is optimized for automotive applications with low power loss and high efficiency — the maximum leakage current is only 20mA at high-temperature operation. The series includes 5A/10A/15A forward current and the maximum VRRM is 45V/60V. All these features are packed into the SMPC4.6U (TO-277A compatible) package. SMPC4.6U has a wettable flank package that enhances the solder joint and AOI testability. Designers benefit from a very low profile with a typical height of 1.1mm. The series is RoHS compliant and halogen-free.
Applications
Board-level heat sinks are so named because they are generally attached both to the device and the PCB. Usually constructed as either a stamping or an extrusion, these heat sinks are designed for common package sizes like T0220, T0247, and D2pak. Stamped heat sink can have features that clip onto the device so that a screw or secondary clip is not required. Stamped heat sinks have bent/twisted fins to improve the thermal performance in either natural or forced convection. Aluminum stampings are anodized for improved performance in natural convection. If the heat sink is to be mounted to the PCB, then a solderable tab or pin can be attached to the heat sink.
BGA heat sinks are so named because they are mounted to BGA devices, but are actually just simple extrusions. BGA heat sinks are usually crosscut to convert the extruded fins into pins that allow them to be used in more diverse applications. The number and size of the crosscuts are dependent upon the environment. Because BGA heat sinks are generally small, the attachment of the heat sink is a challenge. The heat sinks can be either attached to the device or to the PCB depending upon the application and the mechanical requirements. Thermal tape/Epoxy is a common method usually associated with low-power devices. While not the best thermal interface material, they serve their purpose.
Pushpins are another common attachment method and require two small holes in the PCB. Because the holes are generally just outside the boundaries of the device, they can make chip routing difficult. The pushpin, which can be made from plastic or metal, uses the energy of a small spring to provide enough force to keep the heat sink in place.
In cases where the pushpin’s holes are not practical, anchors and wire clips can be used as an alternative. The anchors are either soldered to the PCB using two small holes per anchor or can be installed in a routed slot in the PCB. In the case of the slot, the anchor is installed from the back side of the PCB and is held in place by the compression force in the anchor design. The advantage of the anchors is that their location is much more flexible and can be moved out of the way of traces in the PCB. A wire clip is a small diameter wire that is bent into various shapes that when deformed, engages with the anchors and applies a force to the heat sink to hold it in location. The actual shape of the wire clips is dependent upon the location of the anchors, the heat sink design, and the amount of force required. Multiple wire clips can be used with a single heat sink in applications where a higher force is required. Wire clips are removable and allow the heat sink to be reused in the case of a reworked device.
Since the pushpins and wire clips are a mechanical attachment method, it opens up the type of interface material that can be used between the heat sink and the chip, which can lead to better performance.
Extruded heat sinks are the most common heat sink used for thermal management today. They are manufactured by pushing hot aluminum billets through a steel die to produce the final shape. The most common aluminum alloy is 6063-T5, but other 6XXX alloys can also be examined as needed. When the material is extruded, the initial sticks are 30-40 feet in length and are very soft. The material is stretched by grabbing both ends to produce a straight stick. After stretching, the material can be either air or overaged depending upon the required final hardness of the material. After the aging process, the material is cut to the final length and any final fabrication (holes, pockets, or other secondary machining) can be done. Extruded heat sinks are usually supplied with a “finish” such as anodizing, which can enhance its thermal performance. The heat sinks can also be supplied with a chromate finish which provides some corrosion protection or can be used as a primer before a final paint or powder coating is applied. While each extruded shape is unique to the requirements that it was designed for, extruded heat sinks are the most cost-effective cooling solution. Each shape is engineered to achieve optimal thermal and structural performance. Wakefield Thermal partners with a large list of vendors that ensure that you have the best thermal solution based on your system structure and thermal requirements.
Wakefield Thermal manufactures both custom and standard electronic packaging solutions. In June 2015, Wakefield Thermal announced an exclusive strategic partnership with Heitec AG, a recognized leader in electronic packaging systems (EPS), to sell, customize, and service the Heitec product line (formerly Rittal) to the North American marketplace.
Wakefield Thermal can modify a customer’s unique specification within a quick turnaround time that separates its broad product line from the rest in North America.
Wakefield Thermal has achieved a leading position in the Rugged COTS packaging marketplace, providing for VME/VME64x, VXS/VPX, VXI, PXI, AdvancedTCA, and MicroTCA, and CompactPCI/2.16 architectures.
Heat pipes are a transport mechanism to move heat from the hot source to an area where the heat can be dissipated. Heat pipes do not dissipate the heat and are therefore incorporated into many different types of heat sinks as helpers. A heat pipe is a copper tube with an internal wick structure that is sealed on both ends with a small amount of water inside. As heat is applied to the pipe, the water will boil and turn into a gas, which then travels to the colder section of the heat pipe where it condenses back to a liquid. It is the evaporation and condensing of the water that forms a pumping action to move the water (and thus the heat) along the pipe.
There are many types of wick structures that can be used within the heat pipe and they are generally classified as grooved, mesh, powder, and hybrid. A grooved heat pipe is a copper tube with a series of shallow grooves around the internal perimeter of the heat pipe. While the water is a liquid it travels in the grooves, and while it is a vapor it travels in the open space of the pipe. Grooved pipes can be used in horizontal orientations, but are very limited in performance if used about 15° out of horizontal.
A mesh heat pipe is a smooth-walled copper tube with a woven copper mesh installed along the interior of the pipe. The mesh is designed to remain in contact with the walls of the pipe in areas where the pipe may be bent or flattened. Mesh pipes can be used horizontally and about 30° out of horizontal orientations.
A powder wick heat pipe can also be known as a sintered heat pipe. During the manufacturing process a mandrel is installed in the center of the pipe and copper powder is poured into the pipe around the mandrel. After the powder is sufficiently packed, the parts are placed into a sintering oven. Once at temperature, the copper powder will stick to the pipe and to itself, forming lots of internal pockets like a sponge. Because of the small pocket sizes, sintered pipes can efficiently move the water and can be used horizontally, vertically, and at all points in between, including upside down.
The performance (amount of heat that can be transferred) of a heat pipe is a function of its length, diameter, wick structure, and overall shape. The larger the diameter, the more power that can be transported, but the longer the length, the less capable the pipe. Sintered heat pipes are better than meshed, which are better than grooved. Heat pipes can be bent and flattened in order to move the heat where needed or to fit into smaller spaces, but these types of modifications impact the total heat that can be transported. In cases where the amount of heat needed to be transported is too great for a single pipe, multiple pipes can be used in parallel and series to move more heat over greater distances.
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