Showing papers on "Junction temperature published in 1971"

Temperature sensor employing married diode junction means

Abstract: An improved system employing a plurality of economical, linear and interchangeable temperature sensors, characterized by (1) diode junction temperature sensors that include a plurality of serially connected diode junctions that are preselected to have a predetermined standard operating curve, at a constant current within the range of - 100 DEG F. to + 350 DEG F.; and (2) power supply means and regulator means for maintaining a substantially constant current flowing through the diode junction temperature sensor. Also disclosed are specific embodiments including: (1) temperature sensors connected with an electrical common and employing a single readout lead carrying a signal that is relatively insensitive to the length of the lead, and (2) multiplexing equipment for monitoring a plurality of such readout leads.

High Current Transient Induced Junction Shorts

Abstract: The essential cause for junction shorts is second breakdown which requires thermal gradients and temperature magnitudes in excess of the intrinsic temperature associated with the materials. From the thermal and current gradient analysis, the following was shown: a. The shorts will follow the lowest resistance path. For a typical microcircuit, this path will occur immediately between the nearest aluminum silicon contacts and in the silicon region adjacent to the Si-SiO2 interface. b. The cause of hot spot formation arises primarily from spreading resistance considerations and not from a localized breakdown mechanism. This is true at least for the pulse widths studied here. c. For pulse widths shorter than 10 useconds, there should be no difference in the power required to cause failure and the device technology, i.e., glassivated, junction isolated or dielectrically isolated devices. This is due to the relatively long thermal time constants resulting from either poor thermal conductivity in the case of the glass or long distances from the dissipating junction in the case of dielectric isolation. d. The junction isolated technology should be relatively uniform in terms of power dissipation. e. Combining the results of gradients and magnitude, the cause for the wide spread in power required for failure has not been specifically identified. The differences in technologies cannot be important for these pulse widths, and the spreading resistance associated with the intrinsic temperature, while not identical, should be relatively uniform from one manufacturer to another. f.

Stroboscopic investigation of thermal switching in an avalanching diode

Abstract: A new stroboscopic technique for investigating thermal switching has been used to yield a new model describing the time and spatial development of a thermal‐current constriction evolving out of a uniformly avalanching junction The thermal instability was found to be caused by the buildup of thermally‐generated reverse‐bias diode current as the junction heated The junction temperature at the time the constriction formed was a function of the applied bias The constriction formed in less than 100 nsec in all cases The ability of the constriction to penetrate the series material depended entirely upon whether this material was heated to its instrinsic temperature

High-power parallel-array IMPATT diodes

Abstract: Fabrication of parallel arrays of silicon IMPATT diodes in which the arrays are formed in a single diode chip is described. The technique includes formation of an integral heatsink for the diode arrays during wafer processing. For a given total active device area, the use of a parallel array of smaller diodes, rather than one large diode, allows a significant reduction in thermal impedance and consequently larger power-dissipation capability. The contribution shown in the letter is the ease and economy with which parallel arrays on an integral heatsink can be fabricated and handled as a single entity. In a diode operated at 6.4 GHz, 3.5 W of c.w. output power has been achieved with a room-temperature copper heatsink and a junction temperature of about 280°C.

New Method of Monitoring Junction Temperature

Abstract: A variation of the pulse method of junction temperature measurement is presented. The new technique allows the junction temperature of diodes and transistors under stress test to be monitored by a simple procedure. An expression for correcting junction to case thermal resistances, obtained via the steady-state h rb method, for nonthermal effects is derived. Both of these ideas are illustrated by an example.

A five-terminal, complementary tracking ±15V ±200 mA monolithic voltage regulator

Abstract: This paper will discuss a dual function, single-chip, IC regulator with preadjusted output voltages to within ±1%, internal frequency compensation, current limiting, maximum junction temperature shutdown, and excellent temperature stability due to a thermally symmetric die layout.

Transcalent Silicon Power Rectifier

Abstract: The transcalent rectifier can dissipate power losses while rectifying 250 amperes; it rectified 60-Hz alternating current at conduction angles of 180°, 120°, and 60°, and at frequencies varying from 200 to 2600 Hz at a conduction angle of 180°. It was surge-current tested to a peak of 6500 amperes, life tested for 4108 hours, and cycle-life tested for 10 867 cycles while rectifying 250 amperes of current. The transcalent rectifier dissipates heat more effectively and at lower junction temperature than conventional rectifiers as heat is transferred isothermally by vaporization of liquid in the heat pipe. Operational characteristics are: a thermal impedance of 0.030 C/W between junction and fins; a thermal impedance of 0.21 C/W between fins and ambient; a junction operating at 1300C; size less than 14 cubic inches; and weight less than 10 ounces.

On heat flow resistance evaluation in avalanche diodes

Abstract: Starting from simple experiments and using the definitions given by Haitz, Stover, and Tolar, a different method of evaluating heat flow resistance of avalanche diodes has been developed. It is observed that the heat flow resistance for these devices decreases with increasing current or junction temperature. An improved method of estimating space-charge resistance is described.

Pulse measurements of transient thermal response and temperature of avalanching P-n junction.

Abstract: A method is presented for measuring the junction temperature and the transient thermal response of oscillator-mounted avalanche diodes; the method requires an exact knowledge of the temperature dependence of the diode breakdown voltage. The junction temperature can be measured with unchanged accuracy within the measured temperature range of the breakdown voltage. The transient response as close as a few microseconds after the initiation of the junction-temperature step can be measured.

Time dependence of the shift of the energy of peak emission in GaAs junction lasers operated with a flat-topped current pulse at 77°K

Abstract: The shift of the energy of peak emission resulting from rise of the junction temperature in GaAs junction lasers during operation with a flat-topped current pulse is studied theoretically as a. function of time. The nature of this dependence is found to be in qualitative agreement with the experimental observation of such a dependence in GaAs 1-x P x junction losers as reported elsewhere. The effects of increasing doping and increasing amplitude of the current pulse on the time dependence of the energy shift are also studied. In addition expressions are derived for the maximum time duration of the output light pulse that can be obtained under the limitations of junction heating and the maximum possible shift in the energy of peak emission that may occur as a consequence of such heating.

Reflectivity dependence of the junction temperature rise and the stimulated light power in GaAs junction lasers operated continuously at 77° K

Abstract: The reflectivity dependence of the junction temperature rise, the total stimulated light power and the power efficiency in solution-grown GaAs junction lasers operated continuously at 77° K is studied. It is found that both the stimulated light output and the power efficiency can be maximised at a given current density by changing the laser reflectivity. It is also concluded that even when the laser diode is capable of with-standing a considerable rise in the junction temperature, the operation of the diode with a large biasing current above a certain level may prove not to be useful, as the junction heating will ultimately limit the stimulated light power.

The Computerized use of Transient Thermal Resistance to Avoid Forware Biased Second Breakdown in Transistors

Abstract: The power handling capability of any transistor is limited by its peak junction temperature. Equally as important as the more familiar ICBO thermal runaway is a second, thermally related, phenomenon called forward biased second breakdown (S/B). Much has been written on S/B (see Ref. 1 for a thorough description and bibliography) but it is sufficient here to say that S/B is a potentially destructive phenomena that can occur in any bipolar transistor when the energy absorbed exceeds a critical value and creates a hot spot within the pellet. If the temperature of the hot spot is left unchecked, it will eventually cause the space-charge layer to collapse resulting in the transistor assuming a low resistance state.

Spatially separated, series-linked thermocouples

Abstract: Series-linked thermocouples can be used to average random heat fluctuations in flames and to reduce the amount of input data necessary to evaluate flame temperatures. Techniques that allow computation of average temperature are described and evaluated both theoretically and experimentally.