Galinstan, a gallium, indium, and tin eutectic, may be exploited for enhanced cooling of microelectronics because its favorable thermophysical properties. A careful evaluation potential, however, has not been undertaken. Provided here is first-order model to compute the total (i.e., caloric plus conjugate conduction convection) thermal resistance galinstan-based heat sinks. Geometrically optimized minichannel sinks with rectangular channels surface area enhancement minigap, i.e., single...

Microchannel heat sinks are a relevant thermal management technology because the combination of surface area enhancement and small length scales results in low wall-to-bulk temperature differences. Previously, resistance 0.09°C/W was achieved when flux 790 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> imposed on 1 cm × footprint portion 400-μm-thick Si substrate utilizing single-phase water-based microchannel cooling 214 kPa...

A novel control technique is described which leads to the enhancement of mixing in axisymmetric jets. The approach relies on self-excitability jet and does not require elaborate feedback schemes or actuators. Self-excited global oscillations are established by applying suction an annular cavity placed around periphery. These responsible for enhanced between surrounding fluid, can be maintained at relatively low levels counterflow. Furthermore, increased appear insensitive initial conditions....

This paper describes a 1 mm thick substrate with integrated flow channels to circulate liquid metal that is pumped an electromagnetic pump. The was fabricated using conventional circuit board assembly methods. Tests were performed pumping current of up 10 amps, which corresponded power 450 mW. testing showed the had effective thermal conductivity more than 6000 W/mK. thin geometry and organic materials allow it be mechanically compliant therefore can reduce need for gap fillers connect...

Galinstan, a gallium, indium and tin eutectic, may be exploited for enhanced cooling of microelectronics due to its unique thermophysical properties. However, critical evaluation the potential galinstan has not been undertaken. Provided here is first-order optimization model minimize total thermal resistance galinstan-based heat sinks under constraints on form factor pressure drop. The geometry considered minichannel sink that includes millimeter-scale rectangular channels provide surface...

Rockwell Collins has recently developed a light engine, which uses four emitting diodes (LEDs) as the source, for cockpit display system. Under worst case operating conditions, local heat flux from these LEDs can be more than 1000 W/cm <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . This paper describes thermal management approach engine and presents results of finite element modeling. modeling was used to assess various design aspects...

Electronic components, such as ball grid array (BGA), chip scale packages (CSP) and bottom terminated components (BTC) used in harsh use environments often require the of conformal coatings to meet reliability requirements. In certain coating application methods, materials can flow underneath component cause solder joint failure during thermal expansion contraction electronic assembly. this study, BGA were coated with an acrylic material using two methods subjected different cycling profiles...

Liquid metals, such as Galinstan, a gallium, indium and tin eutectic, may be exploited for enhanced cooling of microelectronics due to their favorable thermophysical properties. Hodes et al. [1] discussed the properties Galinstan compared with those water provided first-order model minimizing total thermal resistance Galinstan-based heat sinks under form factor pressure drop constraints. This paper, follow up, describes fabrication assembly water-based microchannel minichannel sinks. <sup...

Abstract Protecting electronic components at harsh environments and applications often requires the use of conformal coatings, underfills or potting compounds. The temperature dependent properties these materials greatly depend on their chemical formulation. Conformal coatings used for are available in a variety ranging from silicones, acrylics, polyurethanes, paralyne epoxies. glass transition (Tg) varies each material represents phase change hard glassy one to soft rubbery state....

The implementation of the Restriction Hazardous Substances (RoHS) European Union (EU) Directive in 2005 resulted introduction pure tin as an acceptable surface finish for printed circuit boards and component terminations. A drawback finishes is potential to form whiskers. Tin whiskers are a metallurgical phenomenon that associated with rich/pure materials has been topic intense industry interest. acceptance usage by electronics fabricators understandable inexpensive, simple plating systems...

The geometry and loss characteristics of 50-/spl Omega/ striplines operating at a frequency 1.09GHz, which corresponded to the requirements for an existing military radio system, were estimated using fundamental transmission line theory. These results then combined with finite element based thermal modeling estimate temperature rise within stripline. predictions validated measurements on circuit board used in avionics power amplifier. this analysis showed that higher dielectric materials...

Test vehicles were assembled with Quad Flatpack No-lead (QFN) components and subjected to thermal cycle conditioning. Components inspected measure voiding within the component pads for different solder alloys configurations of microvias in test boards. The resulting distributions showed that lead-free solders had substantially more presence increased voids tin-lead solder. Thermal modeling was used assess whether these would adversely affect characteristics QFN. This indicates range measured...

We describe the use of direct liquid cooling to improve performance an X-band GaN HEMT based power amplifier Monolithic Microwave Integrated Circuit. With improved cooling, operating drain bias was increased from 20V 44V and PA MMIC delivered 5.1W/mm density while dissipating 8.9W/mm thermal under continuous wave condition.

This paper describes a family of composite materials that are based on Alkali Silicate Glass (ASG), which can be processed and cured at temperatures compatible with conventional electronics packaging processes. The focus this is ASG high thermal conductivity filler for use as encapsulants adhesives in packaging. Data presented testing test die encapsulated an ASG-diamond well evaluation using the material to adhere inductor coil circuit board. These results indicated exceeded 10 W/mK it...

Microchannel heat sinks are a relevant thermal management technology because the combination of surface area enhancement and small length scales results in low resistance. Previously, resistance 0.09°C/W was achieved when flux 790 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> imposed on 1 cm × footprint portion 400 μm-thick Si test specimen utilizing single-phase microchannel cooling. Water driven through assembly with 214 kPa...

A criterion for comparing the relative performance of various heat transfer augmentation methods used in constant power input systems is introduced. The analysis based on principle minimizing rate total entropy generation. load (HTL), a parameter determined by operating requirements dissipating process that indicates difficulty duty to be performed, defined present study. By irreversibility distribution ratio (φ) configurations at given load, most exergy efficient system can selected. data...

The geometry and loss characteristics of 50 /spl Omega/ striplines operating at a frequency 1.09 GHz were determined using fundamental transmission line theory. These results then combined with finite element based thermal modeling to estimate the temperature rise within stripline. predictions validated measurements on circuit board used in an avionics power amplifier. this analysis showed that higher dielectric materials have compared traditional lower materials. But, due conductivity these...

Thermal test vehicles were fabricated with three different commercially available die attach materials: two Nano-Sintered Silver (NSS) materials and a Filled Die Attach (SFDA). The thermal resistances of individual components determined after their initial assembly as they accumulated total 1500 shocks from -55°C to +125°C. Initial testing showed that the package-level resistance NSS was approximately half SFDA. This improvement maintained during course cycling, in which average all packaged...

Soldiers and Marines rely on electronics for communication, navigation situational awareness. Increasing these capabilities, such as with longer range higher bandwidth generally comes at a price of greater power consumption corresponding increase in system dissipation/thermal load. This increased dissipation can limit the functional capabilities systems when used thermally challenging environments. One environments is inside packs by dismounted troops. paper presents results testing to...