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Showing papers on "Junction temperature published in 1976"


Journal ArticleDOI
TL;DR: In this paper, the idealized concept of thermal resistance as applied to power transistors is discussed and various electrical methods for measuring the junction temperature (thermal resistance) of transistors with the emphasis placed on the emitter-only switching measurement technique, which is the preferred standard method of measurement.
Abstract: The idealized concept of thermal resistance as applied to power transistors is discussed. This concept must be used with care because two of the basic assumptions made in applying the concept to these devices are not valid. Contrary to these assumptions, it is shown that 1) the junction temperature of a power transistor is never spatially uniform, and 2) no unique value of thermal resistance can be defined for all operating conditions. Also, various electrical methods for measuring the junction temperature (thermal resistance) of power transistors are discussed with the emphasis placed on the emitter-only switching measurement technique, which is the preferred standard method of measurement. In addition, the generation and meaning of forward-biased safe-operating-area (SOA) limits are discussed, and it is shown that because of the presence of current crowding and the associated hotspots, the specified SOA limits often permit devices to be operated at dangerously high junction temperatures. Electrical measurement methods capable of determining the peak junction temperature as well as determining the onset of current crowding are described, and it is shown how these methods might be used for the generation of improved SOA limits.

109 citations


Patent
19 Jul 1976
TL;DR: In this paper, a bias control for an operating circuit for a semiconductor switch device of the type that passes electrical current from a source to an electrical load by forward bias of the semiconductor's control terminal is presented.
Abstract: An operating circuit for a semiconductor switch device of the type that passes electrical current from a source to an electrical load by forward biasing of the semiconductor's control terminal includes a resistance bridge network having in an arm thereof the control terminal to one main terminal circuit of the semiconductor switch, and a bias control for alternately applying forward bias and reverse bias to the control terminal through the bridge network, whereby a voltage is developed across the bridge output during the interval in which the control terminal is reverse biased that is representative of the junction temperature within the semiconductor. The temperature representative voltage is observed, monitored, and used for indication and control. In a further embodiment the bias control operated periodically and includes inhibit means responsive to the derived temperature representative voltage exceeding a certain level, representative of a temperature maximum, for retaining the control terminal of the semiconductor in the back biased condition, until the derived voltage reduces in level thereby protecting the semiconductor from thermal burn-out. In a welding control circuit presented herein the foregoing bias control is adapted in an intra-phase control circuit.

34 citations


Journal ArticleDOI
TL;DR: In this paper, a depletion MOS transistor is proposed, which uses anisotropic etching to define the channel in an n/p epitaxial silicon slice and is capable of delivering up to 12W with a cutoff frequency of 80 MHz.
Abstract: A new depletion MOS transistor is proposed. The structure uses anisotropic etching to define the channel in an n/p epitaxial silicon slice. A simple planar model is developed to explain the characteristics of the devices and is verified by measurements on experimental structures. Power devices are fabricated to illustrate the power capability of the structure. Parameters measured for this structure include: junction temperature, d.c. power dissipation, distortion, ac output power, efficiency. The devices were found to be capable of delivering up to 12W with a cutoff frequency of 80 MHz.

21 citations


Journal ArticleDOI
H.M. Olson1
TL;DR: In this paper, a model for computing the thermal transient response of a diamond-heat-sinked IMPATT diode has been formulated as a means for accurately predicting the degree of heating or cooling of the junction when the diode is pulsed into or out of avalanche.
Abstract: A model for computing the thermal transient response of a diamond-heat-sinked IMPATT diode has been formulated as a means for accurately predicting the degree of heating or cooling of the junction when the diode is pulsed into or out of avalanche. The model consists of an electrical network analog for the heat conduction process, and the transient analysis of this network has been performed using the IBM Advanced Statistical Analysis Program (ASTAP). Also incorporated into the model are the results of previous numerical determinations of steady-state temperature distributions in IMPATT diamond heat sinks. The thermal responses for diode turnon and turnoff and for power surges have been found for several different designs of IMPATT diodes, both Si and GaAs. Turnon transients calculated with this model have been compared with transients calculated by a published method [11] involving a transcendental equation. The two models were roughly in agreement. However, because the previously published method neglects the heat flow path through the chip, it yielded lower values than the network analog model described here for the junction temperature in the first few microseconds after turnon of the diode. The results of these calculations showed that the transient response varied depending on the size of the chip and that significant temperature changes occurred in time intervals ranging from less than 0.1 µs to several microseconds for practical diodes. The results also showed that a description of the transient response in terms of a simple time constant is not meaningful, because the early response does not approximate an exponential curve. To provide a means for making quite accurate desk calculations of diode thermal transients, two approximations have been derived which can be used without computer programs.

19 citations


Journal ArticleDOI
TL;DR: The capacity of a solid-state device, as ordinarily rated, varies widely depending on the current waveform, duty cycle, case temperature, etc. The underlying junction temperature limits should, however, be invariant as discussed by the authors.
Abstract: The current capacity of a solid-state device, as ordinarily rated, varies widely depending on the current waveform, duty cycle, case temperature, etc. The underlying junction temperature limits should, however, be invariant.

6 citations


Journal ArticleDOI
TL;DR: In this paper, a computer analysis of the temperature dependence of emitter junction voltage under an assumed nonuniform temperature distribution is presented, which demonstrates a temperature averaging effect when using junction voltage as an indicator of junction temperature.
Abstract: A computer analysis of the temperature dependence of emitter junction voltage under an assumed nonuniform temperature distribution is presented, which demonstrates a temperature averaging effect when using junction voltage as an indicator of junction temperature.

3 citations


Journal ArticleDOI
TL;DR: This paper describes the reliability design and performance of 86-GHz active components and transmitter-receiver modules for a guided millimeter-wave transmission system with considerations for reliability as well as RF performance.
Abstract: The reliability of semiconductor active devices is related to the junction temperature of diodes used. This paper describes the reliability design and performance of 86-GHz active components and transmitter-receiver modules for a guided millimeter-wave transmission system. The components are IMPATT oscillators, IMPATT amplifiers, varactor frequency multipliers, and Schottky-barrier diode upconverters. The maximum output powers of these active devices are calculated for a given mean time between failure (MTBF). Active components and transmitter-receiver modules for 86-GHz operation were manufactured based upon the design with considerations for reliability as well as RF performance.

2 citations


Journal ArticleDOI
TL;DR: In this paper, a distributed feedback GaAs-GaAlAs diode laser with a separate confinement heterostructure was fabricated and operated successfully at room temperature under pulse and DC bias.
Abstract: Distributed feedback GaAs-GaAlAs diode lasers with a separate confinement heterostructure are fabricated and operated successfully at room temperature under pulse and DC bias. A threshold current density of 3.4 kA/cm2 is obtained at junction temperature Tj=320 K. The lasing spectra are examined closely, and single longitudinal mode oscillation is ascertained up to twice the threshold current density.

2 citations


Journal ArticleDOI
Er-Yung Yu1
TL;DR: In this article, an infrared technique and an analogical method to determine the maximum temperature of a beam-leaded integrated-circuit chip, mounted on a ceramic carrier are described.
Abstract: This paper describes an infrared technique and an analogical method to determine the maximum temperature of a beam-leaded integrated-circuit chip, mounted on a ceramic carrier. The infrared technique employs a color thermogram camera to map the stepwise temperature distribution of a heated surface. From the color-digitized thermograms the chip temperature rise over the ambient air can be computed with the aid of thermocouple measurements. The color thermograms also help evaluate the thermal resistances of the chip and the ceramic carrier, which are used in the thermoelectric analogical analysis of steady-state heat flow from the chip t,o the surrounding air under free convection condition. The chip temperature rise as evaluated by the thermoelectric analysis checks reasonably well with the infrared and thermocouple measurements. These two methods have their respective advantages in determining the temperature of integrated-circuit chips.

1 citations


Book ChapterDOI
Adolph Blicher1
01 Jan 1976
TL;DR: In this article, the authors assume that the heat is generated in the thyristor in the plane passing through the device center and parallel to the center junction in either the blocking or conducting mode.
Abstract: Heat is generated in a thyristor when it is in either the blocking or the conducting mode. In the first case, the heat generation takes place primarily at the reverse-biased blocking junction. For the case of forward conduction, it is customary to assume (for simplification) that the heat is generated in the thyristor in the plane passing through the device center and parallel to the center junction.