Browse Prior Art Database

Dynamic Burn-in of VLSI Products by Power Supply Cycling

IP.com Disclosure Number: IPCOM000109121D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Lepore Jr, MA: AUTHOR [+4]

Abstract

A method of generating dynamic stimuli for exercising VLSI product during burn-in to improve field reliability is disclosed. The technique involves cycling power supply voltages to cause changes in voltage levels and current sharing in the internal circuits. This provides simple and efficient stimuli equivalent to the ones generated by applying pre-designed patterns to the chip.

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Dynamic Burn-in of VLSI Products by Power Supply Cycling

      A method of generating dynamic stimuli for exercising VLSI
product during burn-in to improve field reliability is disclosed.
The technique involves cycling power supply voltages to cause changes
in voltage levels and current sharing in the internal circuits.  This
provides simple and efficient stimuli equivalent to the ones
generated by applying pre-designed patterns to the chip.

      In the figure a typical current switch emitter follower two-way
NOR/OR gate is shown in which Vcc, Vee, Vt, Vr are power supplies,
and V2, V3 are the inputs, and V1, V4 are the outputs.  It is
desirable to be able to switch the current between the references
transistor (T4) and input transistors (T2, T3) for dynamic burn-in
purpose.  When Vt is raised to a voltage higher than Vr, the output
levels V1 and V4 are forced to be higher than Vr.  In the circuit
described in the figure, V2 and V3 are higher than Vr, and the
current is flowing in the input transistors T2 and T3.  Transistors
T1 and T5 are turned on with nominal Vt, and are turned off when Vt
is raised.

      When Vr is raised to higher than the high logic level, or Vcc
is lowered to force the normal high logic level to be lower than Vr,
current is directed to the reference transistor T4.

      Disclosed anonymously.