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Transistor Breakdown Test

IP.com Disclosure Number: IPCOM000082297D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Lim, HS: AUTHOR

Abstract

This is a breakdown test providing a nondestructive means for checking the reverse-biased secondary breakdown capability of transistors. Other methods are available, but mostly are copies of real-life applications with a shut off feature added, and as such can still be destructive.

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Transistor Breakdown Test

This is a breakdown test providing a nondestructive means for checking the reverse-biased secondary breakdown capability of transistors. Other methods are available, but mostly are copies of real-life applications with a shut off feature added, and as such can still be destructive.

Fig. 1 shows the breakdown test circuit in its basic form. A very fast-rise pulse (dv/dt larger than two kilovolts per microsecond) is applied to the collector of the transistor-under-test (TUT) 8. The collector current is sensed by current probe 12. Emitter bias (V(E)) 6 determines the level of reverse-bias applied to the TUT 8.

Fig. 1A shows the applied pulse to the TUT's collector. The amplitude must be greater than the TUT's BV(ceo).

Figs. 1B and 1C show collector voltage and current, respectively, of a TUT 8 that does not show secondary breakdown under the biasing conditions determined by V(E) and R(B).

Figs. 1D and 1E show collector voltage and current of a TUT 8 going into secondary breakdown, under the specific conditions set by V(E) and R(B). Current limiting resistor R 14 limits the collector current after secondary breakdown occurs.

The basic circuit shown can be modified and made more spohisticated, as well as automated for production testing.

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