Abstract: A wafer containing an array of integrated circuit dice, wherein the dice are separated by scribe lanes in which the wafer may be cut to dice the wafer into individual die, is so constructed as to enable burn-in testing of the integrated circuits while they are still in the wafer. In this wafer, individual integrated circuits of the array include contact pads that extend into the scribe lanes for use during burn-in testing of the integrated circuits while they are contained in the wafer. A system for testing such a wafer includes a testing station for applying and monitoring burn-in test signals for individual integrated circuits; and contact probes for coupling the testing station to the contact pads for a plurality of the individual integrated circuits to enable separate burn-in tests to be conducted simultaneously for a plurality of the individual integrated circuits while they are contained in the wafer.

Abstract: A TTL-level-output interface circuit includes a biCMOS inverter coupled between a voltage supply terminal and a ground terminal; a first npn transistor coupled between the voltage supply terminal and a TTL interface terminal and a second npn transistor connected in series with the first npn transistor between the TTL interface terminal and the ground terminal; an n.phi. network coupled between the TTL output terminal and the base of the second npn transistor by an n-channel MOSFET, which has its gate connected to the inverter input terminal. When a high input signal is applied to the inverter input terminal, the n-channel MOSFET couples the n.phi. network to the base of the second npn transistor, in order both to limit the base current of the second npn transistor in order to prevent saturation of the second npn transistor, and to enable current to be conducted to the base of the second npn transistor 56 through the n.phi.

Abstract: In a microcircuit employing LSSD boundary scanning, input and output cells of the circuit are tested using the LSSD boundary scan circuity. Input cells of the circuit are tested by applying two voltages alternately to input cell signal pads and capturing and shifting out through input boundary scan circuitry the responses of the input cells to the voltages. Output cells are tested by shifting a predetermined test pattern through the output boundary scan circuitry. The pattern encloses a set of significant bits which is applied sequentially to the output cells. Each output cell has a gated signal path connecting its signal pad to an internal signal conductor which conducts the response of the output cell to an internal signal path as the significant bits of the bit pattern are scanned past the cell.

Abstract: A pair of bipolar transistors are connected in totem-pole fashion to provide an emitter-collector output connection. A pair of complementary MOS field-effect transistors are connected in push-pull fashion for each receiving a common input signal on a gate thereof and for driving a base of a corresponding one of the bipolar transistors. Resistors are connected to the field-effect transistors for isolating the output connection and substantially eliminating crowbar current.