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Measuring the Internal Thermal Resistance of Transistors and Integrated Circuits

IP.com Disclosure Number: IPCOM000090998D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Mesples, PM: AUTHOR [+2]

Abstract

High volume testing with direct readout of thermal resistance R(T) is available with this circuit. Initially the device 10 under test DUT is elevated in temperature and the base-to-emitter voltage V(BE) is determined with 500 uA base current flowing and negligible applied power. The value of 500 uA base current minimizes heating of the junction while overriding any possible internal noise current. The arrangement is then operated in the powering mode. Sample and hold circuit 20 and comparator circuit 30 operate to bring V(BE)' within 1 mV of the reference V(BE). During a 50 uA sampling period, power is removed and the 500 uA base current is again allowed to flow. At equilibrium, the junction temperature and that of the case are known and the power dissipated in device 10 is automatically measured.

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Measuring the Internal Thermal Resistance of Transistors and Integrated Circuits

High volume testing with direct readout of thermal resistance R(T) is available with this circuit. Initially the device 10 under test DUT is elevated in temperature and the base-to-emitter voltage V(BE) is determined with 500 uA base current flowing and negligible applied power. The value of 500 uA base current minimizes heating of the junction while overriding any possible internal noise current. The arrangement is then operated in the powering mode. Sample and hold circuit 20 and comparator circuit 30 operate to bring V(BE)' within 1 mV of the reference V(BE). During a 50 uA sampling period, power is removed and the 500 uA base current is again allowed to flow. At equilibrium, the junction temperature and that of the case are known and the power dissipated in device 10 is automatically measured. This data is applied to analog computer 40 for a direct reading of R(T) on meter 50. Device 10 can be a transistor as shown or an integrated circuit, the R(T) of which is of importance in high-power density devices.

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