When a designer has to deal with thin current-carrying wires, a number of thermal issues pop up: Joule heating, heat losses and temperature measurement. For standard lead wires, one usually wants minimal Joule heating and minimum thermal resistance (in order to maximize the heat losses). Minimization of heat losses may be important for a research environment. Maximum Joule … [Read more...]
Optical instrumentation for the thermal characterization of electronic devices
What information does light, reflected from a running electronic device, carry? Our research team has been working upon this key question for almost a decade. As this magazine is dedicated to thermal issues, we will focus upon these aspects of optical probing. Figure 1 shows the general principle of our experimental method. Light is shone upon a running device. When the device … [Read more...]
Characterizing a package on a populated printed circuit board
This column has emphasized methods of analyzing packages in the JEDEC-standard test environment. A thermal metric that lends itself to analyses of system applications is the junction-to-board thermal characterization parameter, JB. If one knows the board temperature (TB), then the junction temperature (TJ) can be determined by a simple application of the following formula: TJ … [Read more...]
The submerged double jet impingement (SDJI) method for thermal testing of packages
Over the past decades, the functionality of electronic parts has improved considerably. Increasing power requirements of semiconductor chips make it difficult to keep the temperature below the imposed limits. Thermal management of the chip is one of the main functions of the package. To fully characterize the package thermally, numerical simulations and experimental tests are … [Read more...]
Thermal characterization of power ICs using virtual junction temperature
Thermal experts generally view thermal resistance as a measurable property of a semiconductor device. A system designer, who designs an appliance, is usually not a thermal expert. The system designer just needs a way to determine the size of the external heat sink. At high heat sink temperatures, less power dissipation is allowed in the device. The ratio at which case … [Read more...]
