Numerical Study and Experimental Validation of the Thermal Performance for a Parallel Channel Optical Module

To meet the insatiable demand for data bandwidth in VSR (very short reach up to 300m) applications including server and routers, parallel optical interconnection offers a promising solution in terms of performance and cost effectiveness. A 12-channel pluggable paralle optical transmitter module has been developed to achieve a data rate of 2.5 Gb/s per channel. To maintain the robustness of the optical signal integrity under different environmental conditions, the thermal management is crucial. In this paper the thermal performance evaluation of the optical module was carried out through both numerical simulation and experimental verification. The optical module mainly consists of a VCSEL (vertical cavity surface emitting laser) array, a driver IC and a heat sink. Three types of heat sinks were integrated into the transmitter module separately. The thermal environments used for this evaluation include the normal and high ambient temperature, and both still-air and forced-air conditions. The ambient temperature and the wind speed were controlled by using a Wind Tunnel. The simulation was performed by using a CFD (computational fluid dynamics) program. In all the three modules, the simulation and experimental results of the junction temperature have shown good agreements. For Module 1 under the high ambient temperature, a forced-air condition was required to keep the junction temperature below 70°C. For Module 2 and Module 3, the junction temperature can be controlled below 70°C even under the high ambient temperature without using a fan.

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Thermal Performance Optimization of Radio Frequency Packages for Wireless Communication

Journal of Electronic Packaging ◽

10.1115/1.1827257 ◽

2004 ◽

Vol 126 (4) ◽

pp. 429-434 ◽

Cited By ~ 3

Author(s):

Victor Adrian Chiriac ◽

Tien-Yu Tom Lee ◽

Vern Hause

Keyword(s):

Wireless Communication ◽

Thermal Resistance ◽

Thermal Performance ◽

Performance Optimization ◽

Numerical Study ◽

Metal Layer ◽

Peak Temperature ◽

Junction Temperature ◽

Board Structure ◽

Die Attach

The increasing trend in power levels and associated densities leads to the need of design thermal optimization, either at the module level or at the system (module-board stack-up) level. The wireless communication industry is facing multiple challenges as it tries to promote smaller, faster and cost-effective packages, yet trying to cope with potential thermal bottlenecks. The present study investigates a family of packages, whose thermal and electrical performances are far superior to the classic (standard) packages. A three-dimensional conjugate numerical study was conducted to evaluate the thermal performance of gallium arsenic die packaged in quad flat no-lead (QFN) packages for various wireless and networking applications. Two different QFN packages are investigated: a standard package and a power package (PQFN) with thicker leadframe and solder die attach. The thermal impact of die attach material, leadframe thickness, die pad size, and board structure is evaluated and provides valuable information for product designers. Two powering scenarios are investigated: (1) one for standard operating parameters and (2) an alternative for extreme operating powering scenarios. Results indicate that the peak temperature reached on the die for 3×3 mm QFN under normal powering conditions is ∼138.5 °C (or 119 °C/W junction-to-air thermal resistance), while for the extreme scenario, the junction temperature is ∼186 °C (or 125 °C/W junction-to-air thermal resistance). In both cases, the top Au metal layer has a limited impact on lateral heat spreading. Under extreme powering conditions, the 5×5 mm PQFN package reaches a peak temperature of ∼126 °C (66 °C/W thermal resistance). A ∼32% reduction in peak temperature is achieved with the 5×5 PQFN package. The improvement is mainly due to the larger package size, high conductivity die attach material, thicker leadframe, and additional board thermal vias. A parametric study shows that the increase in leadframe thickness from 0.2 mm (8 mils) to 0.5 mm (20 mils) in the QFN package will lead to only 3% reduction in peak temperature. By comparison, for both packages, the die attach material (conductive epoxy versus solder) will have a significant impact on the overall reduction in peak temperature (∼12%). Experimental measurements using an infrared microscope are performed to validate the numerical results. The results indicate good agreement (∼6% discrepancy) between the numerical model and the measurement.

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Study on Junction Temperature Management of White pcLED at High Ambient Temperature in Industrial Environment: An Indian Perspective

2021 Devices for Integrated Circuit (DevIC) ◽

10.1109/devic50843.2021.9455795 ◽

2021 ◽

Author(s):

H. Bhattacharjee ◽

A. Chakraborty ◽

R. Ganguly ◽

M. Mitra

Keyword(s):

Ambient Temperature ◽

High Ambient Temperature ◽

Junction Temperature ◽

Temperature Management ◽

Industrial Environment ◽

Indian Perspective

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Thermal Performance Optimization of RF Packages for Wireless Communication

Heat Transfer, Volume 1 ◽

10.1115/imece2003-42171 ◽

2003 ◽

Cited By ~ 2

Author(s):

Victor Adrian Chiriac ◽

Tien-Yu Tom Lee ◽

Vern Hause

Keyword(s):

Wireless Communication ◽

Thermal Resistance ◽

Thermal Performance ◽

Performance Optimization ◽

Numerical Study ◽

Metal Layer ◽

Peak Temperature ◽

Junction Temperature ◽

Board Structure ◽

Die Attach

The increasing trend in power levels and associated densities leads to the need of design thermal optimization, either at the module level or at the system (module-board stack-up) level. The wireless communication industry is facing multiple challenges as it tries to promote smaller, faster and cost-effective packages, yet trying to cope with potential thermal bottlenecks. The present study investigates a new family of packages, whose thermal and electrical performances are far superior to the classic (standard) packages. A 3-D conjugate numerical study was conducted to evaluate the thermal performance of Gallium Arsenic (GaAs) die packaged in Quad Flat No Lead (QFN) packages for various wireless and networking applications. Two different QFN packages are investigated: a standard package and a Power package (PQFN) with thicker leadframe and solder die attach. The thermal impact of die attach material, leadframe thickness, die pad size, and board structure is evaluated and provides valuable information for product designers. Two powering scenarios are investigated: 1) one for standard operating parameters and 2) an alternative for extreme operating powering scenarios. Results indicate that the peak temperature reached on the die for 3×3 mm QFN under normal powering conditions is ∼138.5°C (or 119°C/W junction-to-air thermal resistance), while for the extreme scenario, the junction temperature is ∼186°C (or 125°C/W junction-to-air thermal resistance). In both cases, the top Au metal layer has a limited impact on lateral heat spreading. Under extreme powering conditions, the 5×5 mm PQFN package reaches a peak temperature of ∼126°C (66°C/W thermal resistance). A ∼32% reduction in peak temperature is achieved with the 5×5 PQFN package. The improvement is mainly due to the larger package size, high conductivity die attach material, thicker leadframe and more board thermal vias. A parametric study shows that the increase in leadframe thickness from 0.2 mm (8 mils) to 0.5 mm (20 mils) in the QFN package will lead to only 3% reduction in peak temperature. By comparison, for both packages, the die attach material (conductive epoxy vs. solder) will have a significant impact on the overall reduction in peak temperature (∼12%). Experimental measurements using an Infrared (IR) Microscope are performed to validate the numerical results. The results indicate good agreement (∼6% discrepancy) between the numerical model and the measurement.

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Thermal Performance Evaluation of New Power QFN (Quad Flat No Lead) Packages for Automotive Applications

Heat Transfer, Volume 2 ◽

10.1115/imece2004-59628 ◽

2004 ◽

Author(s):

Victor Chiriac ◽

Tien-Yu Tom Lee

Keyword(s):

Steady State ◽

Thermal Performance ◽

Numerical Study ◽

Peak Temperature ◽

Junction Temperature ◽

Automotive Applications ◽

Isothermal Boundary ◽

Die Attach ◽

Transient Thermal ◽

The Impact

An extensive 3-D conjugate numerical study is conducted to assess the thermal performance of the novel Power Quad Flat No Lead (PQFN) packages for automotive applications. Several PQFN packages are investigated, ranging from smaller die/flag size to larger ones, single or multiple heat sources, operating under various powering and boundary conditions. The steady state and transient thermal performance are compared to those of the classical packages, and the impact of the thicker lead frame and die attach material on the overall thermal behavior is also evaluated. Under one steady state (1W) operating scenario, the PQFN package reaches a peak temperature of ~106.3°C, while under 37W@40ms of transient powering, the peak temperature reached by the corner FET is ~260.8°C. With an isothermal boundary (85°C) attached to the board backside, the junction temperature does not change, as the PCB has no significant thermal impact. However, when the isothermal boundary is attached to package bottom, it leads to a drop in by almost 20% after 40 ms. Additional transient cases are evaluated, with an emphasis on the superior thermal performance of this new class of power packages for automotive applications.

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The influence of high ambient temperature during gestation on the development of wool follicles in the fetal lamb

Reproduction ◽

10.1530/jrf.0.0280151 ◽

1972 ◽

Vol 28 (1) ◽

pp. 151-152 ◽

Cited By ~ 2

Author(s):

G. Cartwright

Keyword(s):

Ambient Temperature ◽

High Ambient Temperature ◽

Fetal Lamb

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An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

Wasit Journal of Engineering Sciences ◽

10.31185/ejuow.vol7.iss1.113 ◽

2019 ◽

Vol 7 (1) ◽

pp. 43-53

Author(s):

Abbas Jassem Jubear ◽

Ali Hameed Abd

Keyword(s):

Heat Transfer ◽

Steady State ◽

Natural Convection ◽

Thermal Performance ◽

Heat Sink ◽

Numerical Study ◽

Ansys Fluent ◽

Fluent Software ◽

Steady State Heat ◽

Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model. The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

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Spray Cooling for Time Resolved Emission Measurements of ICs

ISTFA 2004: Conference Proceedings from the 30th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2004p0018 ◽

2004 ◽

Author(s):

Rama R. Goruganthu ◽

David Bethke ◽

Shawn McBride ◽

Tom Crawford ◽

Jonathan Frank ◽

...

Keyword(s):

Heat Flux ◽

Thermal Performance ◽

Flip Chip ◽

Cooling System ◽

Spray Cooling ◽

Junction Temperature ◽

Maximum Temperature ◽

Uniform Heat Flux ◽

High Heat Flux ◽

Time Resolved

Abstract Spray cooling is implemented on an engineering tool for Time Resolved Emission measurements using a silicon solid immersion lens to achieve high spatial resolution and for probing high heat flux devices. Thermal performance is characterized using a thermal test vehicle consisting of a 4x3 array of cells each with a heater element and a thermal diode to monitor the temperature within the cell. The flip-chip packaged TTV is operated to achieve uniform heat flux across the die. The temperature distribution across the die is measured on the 4x3 grid of the die for various heat loads up to 180 W with corresponding heat flux of 204 W/cm2. Using water as coolant the maximum temperature differential across the die was about 30 °C while keeping the maximum junction temperature below 95 °C and at a heat flux of 200 W/cm2. Details of the thermal performance of spray cooling system as a function of flow rate, coolant

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An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

Volume 3: Heat Transfer, Parts A and B ◽

10.1115/gt2006-90006 ◽

2006 ◽

Cited By ~ 3

Author(s):

Michael Maurer ◽

Jens von Wolfersdorf ◽

Michael Gritsch

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Thermal Performance ◽

Pressure Loss ◽

Numerical Study ◽

Rectangular Channel ◽

Reynolds Numbers ◽

Transfer Enhancement ◽

High Reynolds Numbers ◽

High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

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