Abstract: A content addressable memory consists of a plurality of memory units each of which may be an integrated circuit. Each unit receives an input group of digits forming all or part of an input key code, and compares it simultaneously with a plurality of equally sized groups of digits stored in the memory of the unit. The memory of a unit has 32K bytes of storage elements functionally arranged in 512 rows and column. The 64 bytes forming a row are each compared with an input group of 8 binary digits. A status bit is produced for each of the 64 bytes of a row and indicates whether or not the input group matches the particular byte. The match need not be perfect and certain digits may be masked so that comparison of them does not detract from the match assessment. The status bits are combined logically to produce higher and higher order status bits selectively indicating the presence of a match in larger and larger groups of storage elements up to the entire memory of the unit.

Abstract: A high speed interstage STL buffer (27) is disclosed having a low threshold and high driving capability. A first Schottky-clamped grounded emitter transistor (28) receives input signals through a Schottky steering diode (38) and inverts the input signal. The input signal is applied in parallel through a Schottky steering diode (20) to a second Schottky-clamped grounded emitter transistor (12). The collector (22) of the second transistor (12) provides an output of the buffer (27) for driving load current in one direction with respect to the buffer output. A third transistor (40) connected as an emitter follower has the emitter (42) thereof connected to the buffer output for driving load currents in the other direction. The base (46) of the emitter follower transistor (40) is coupled by a Schottky steering diode (50) to the collector (32) of the first transistor (28).

Abstract: A dual-slope A/D converter circuit has an oscillator (14) whose timing frequency is determined by the value of an oscillator resistor (70) and a oscillator capacitor (72). An integrator (66) integrates an input voltage at a rate determined by an integrating resistor (64) and an integrating capacitor (68). The oscillator resistor (70) and integrator resistor (64) are designed such that their ratio will remain constant despite variations in actual value due to manufacturing inaccuracies. The oscillator capacitor (72) and integrating capacitor (68) are similarly designed. Consequently, an optimum peak integration value can be obtained at full scale input despite variations in actual resistive and capacitive values.

Abstract: A via (64, 66, 68) comprises a conductor (45, 46, 48) having a first surface (58, 60, 62) and at least one second surface (49) that forms at least one edge (52) with the first surface (58, 60, 62). A first insulator layer (33) is formed on the first surface and defines a first area (58, 60, 62) on the conductor that is not covered by the first insulator layer (33). A second insulator layer (70) is formed over the second surface (49). The first and second insulator layers (33, 70) define a via (64, 66 and 68) to the conductor (45, 46, 48) . The bottom area (58, 60, 62) of the via (64, 66, 68) is equal to the first area and is bounded in part by the edge (52).

Abstract: A cascadable first-in, first-out memory unit (11, 12, 13) has a load/unload control (152) for write-addressing and read-addressing selected memory locations within its memory array (82). A write pointer (110, 112, 120) keeps track of the number of write operations that have occurred in the selected memory unit, and a read pointer (130, 132, 142) does the same for the number of read operations. When the number of write operations performed since a last reset pulse (416) equals the number of memory locations in the memory array (82), write control passes to the next succeeding FIFO memory unit by a descending transition of an output control signal (444). Read control is passed to the subsequent FIFO by an ascending transition (470) of the same output control signal.

Abstract: A self-aligned, single polysilicon transistor is fabricated using nitride spacers (26, 68) to self-align the extrinsic base regions ( 48,80). The space between the base contacts (36,76) and the emitter contacts (34,78) is defined by the width of the nitride spacer plug (26,68) less the oxide encroachment from a thermal oxidation of the underlying polysilicon.

Abstract: A multiport random access memory cell includes a current mode latch (68) for storing two logic states and interface circuits for interfacing the input of the latch (68) with multiple input ports and the output of the latch (68) with multiple output ports. The interface circuitry comprises current switches (70-76) for switching current to a current source in the presence of a write select and a row select signal to override the holding current in the current mode latch. The output interface circuitry includes current sensors (78-84) for sensing the logic state in the latch and outputting it to the select output ports in the presence of a row select signal. The current switches and the current sensors utilize current mode logic and with a common current source. The current source is disable in the absence of any row select signal such that power is not drawn by the memory cell in the unselected state.

Abstract: A high efficiency dropout regulator (60) drives an output transistor (22) with a PNP transistor (52) if the overhead voltage from input (14) to output (26) is below a predetermined voltage. If the overhead voltage exceeds the predetermined voltage, then a second PNP transistor (64) and an NPN transistor (72) are used to drive the output transistor (22), resulting in a large reduction of power loss. The current drawn from the output transistor (22) by the NPN transistor (72) is returned to the output.

Abstract: An InP wafer, comprising a S.I. InP substrate, a n-type InP active layer disposed on the substrate and oxygen implanted isolation regions disposed in the active layer.