Abstract: A speed enhancement technique for CMOS circuits is disclosed. In the series of logic stages, nodes in the signal path of a pulse are set by preceding logic stages, then reset by feedback from subsequent logic stages. This eliminates the capacitive burden of resetting any given node from the input signal to allow substantially all of the input signal to be employed in setting the nodes to an active state rather than wasting part of the signal in turning off the reset path. The technique is illustrated as applied to RAM circuits.

Abstract: A buried Schottky clamped transistor is described in which the Schottky diode comprises a region of metal silicide 24 in the epitaxial layer 15 adjacent the transistor. The structure includes an electrically isolated region of N type epitaxial silicon 15 having an upper surface, a region of metal silicide 24 formed in the epitaxial silicon 15 adjacent the upper surface, an emitter region 33 of first conductivity type also formed in the epitaxial silicon adjacent the upper surface, base region 29 of opposite conductivity type adjacent the upper surface which separates the emitter 33 from the metal silicide 24, and metal connections 37, 38 and 39 for making electrical connections to each of the regions of metal silicide 24, the emitter region 33, and the epitaxial silicon 15.

Abstract: A CMOS level shift circuit with active pull-up uses a pair of pull up transistors activated during the period when an output node needs to be rapidly pulled up. The pull up transistors are activated by the outputs of a combinatorial logic or memory circuit detecting when a change of input signal has occurred and activating the respective pull up transistor to bring the output to the proper state.

Abstract: An ECL input buffer is particularly well-suited for use with logic arrays where a large amount of current must be sunk by the row line, for example, when vertical fuse devices are used in an AND array. The input buffer provides means for pulling down the row line such that the entire amount of current sunk by the input buffer from the row line need not pass through a current source, thereby minimizing current consumption of the input buffer. A pull down current source is used which causes a pull down transistor to turn on, thereby pulling down the row line while requiring only the base current of the pull down transistor to be consumed by the current source. A pull up device is utilized and means are included for insuring that the pull up and pull down devices are not both turned on simultaneously, thereby preventing a current spike through the pull up and pull down means.

Abstract: A novel self-timing qualification channel structure is taught, suitable for use in detecting data from a magnetic disk or other storage medium. A timing comparator is used in addition to a hysteresis comparator in order to detect when the true peak of the input signal is about to occur. The timing comparator output determines when signal qualification by the hysteresis comparator is to occur. The timing comparator only allows signal qualification to occur just prior to the true peak in the input signal. Because of this, the risk of falsely detecting off track noise or noise in the shoulder region is greatly reduced. In one embodiment, the timing comparator operates without the need for additional external components by utilizing the existing channel filter. Thus, the channel filter serves two purposes: to filter the channel input signal prior to detection and to provide delay for the timing comparator.

Abstract: A circuit is described for functioning as a transparent latch, a latch where the data is determined by the state of a data signal at the time a signal changes state, a D-type flip-flop, and a scan path element. The mode of operation of the circuit is determined by the condition of respective ones of a set of control signals.

Abstract: A novel sense amplifier is taught which minimizes power consumption by causing selected current sources to conduct current only when an input signal of a selected state is present. The speed of the circuit is fast because capacitance on the critical nodes is minimized by connection of fewer transistors to the critical nodes, as compared with the prior art.

Abstract: There is disclosed herein a base and emitter contact structure for a bipolar transistor which is comprised of a polysilicon stripe over an isolation island which stripe extends to a position external to the position of the isolation island and assumes the shape of an emitter contact pad. The emitter contact stripe has a layer of self aligned silicide formed thereover to lower its resistance, and this silicide is doped with both N and P type impurities one of which is selected to have a higher rate of diffusion than the other. A layer of self aligned insulating material is formed over the silicide and polysilicon of the emitter contact stripe. There are anisotropically etched insulating spacers formed on the sides of the emitter contact stripe, and there are silicide base contact stringers formed beside the spacers by anisotropic etching of a layer of doped silicide.

Abstract: An anti-simultaneous conduction transistor is incorporated into the standard TTL circuit totem pole to reduce simultaneous conduction of the pullup and pulldown transistor elements of the totem pole. The collector of the active discharge anti-simultaneous conduction transistor element (Q5) is operatively coupled to a base of the pullup transistor element (Q2,Q3) through a diode (D5), the emitter is coupled to low potential, and the base is coupled to the base of the pulldown transistor element (Q4) through ballast resistance (R6,R7). The anti-simultaneous conduction transistor element (Q5) mirrors the conducting state of the pulldown transistor element (Q4) without current hogging substantially diverting or discharging base current from the base of the pullup transistor element (Q2,Q3) whenever the pulldown transistor element (Q4) is conducting. Undesirable current spikes in the sourcing current are avoided by preventing simultaneous conduction in the totem pole.

Abstract: A method and structure is provided to test for leakage currents in a fuse array. A diode is connected to each column in the array in order to isolate the column from the test circuitry during normal operation of the device. During testing, current is fed through a diode to a column, and the corresponding leakage current is measured. In one embodiment, the anodes of each diode are connected in common to a single test point, and the total leakage current from the entire fuse array is measured simultaneously. In another embodiment, addressing means are used to selectively address a desired one of the test diodes and thus a corresponding one of the columns such that leakage current through a single column.

Abstract: A CMOS oscillator is disclosed using an inverter in which a pair of control terminals are employed to invoke various sized devices which control the flow of current. The inverter gain is determined by the size of the CMOS devices employed. A tuned circuit coupled to the inverter causes it to oscillate at the frequency of parallel resonance. The control terminals are coupled to the inverter invoke transistors that are sized as desired to establish the current flow and gain in the inverter. The current flow is controlled to optimize the gain of the inverter in terms of the frequency of oscillation. A Schmitt trigger can be employed to clean up the oscillator output for digital clock source applications.

Abstract: When ceramic packages are subjected to lead plating the solutions can reduce the glass oxides and produce metallization of the sealing glass. At best, this metallization is unsightly and at worst results in lead shorting. Such metallization can be greatly reduced or avoided by a pretreatment that passivates the glass. The pretreatment comprises an immersion in an aqueous solution of fluoboric acid or ammonium bifluoride. Improved solutions that additionally contain a wetting agent and other additives are disclosed.

Abstract: A two-level 4:1 ECL multiplexer circuit comprising two 2:1 multiplexer circuits "OR'd" together prior to a shared output stage. A differential Select line, operable at the same voltage level as the input data lines to the 2:1 multiplexer circuits selects one of the input lines to each 2:1 multiplexer circuit. A second Select line, operable at a different voltage level, selects one or the other of the 2:1 multiplexer circuits. This arrangement functions to eliminate an undesirable glitch observed when selecting data inputs in known two-level, 4:1 multiplexers which use emitter dotting.

Abstract: An output buffer for reducing switching induced noise in high speed integrated circuit devices incorporates a relatively small current carrying capacity secondary pulldown transistor element with the current path first and second terminal leads coupled in parallel with the current path first and second terminal leads of the primary pulldown transistor element. A separate pulldown delay resistance element of selected value is coupled in series between the control terminal leads of the secondary and primary pulldown transistor elements. The secondary pulldown transistor element control terminal lead is coupled in the output buffer to receive a signal propagating through the output buffer before the primary pulldown transistor element control terminal lead. A relatively small discharge current is therefore limited from the output before turn on of the relatively large discharge current of the primary pulldown transistor element.

Abstract: Dual phase splitter transistor elements, an output phase splitter transistor element and a secondary phase splitter transistor element, are coupled in current mirror configuration in a TTL output buffer circuit. The output phase splitter transistor element is coupled to the pullup and pulldown transistor elements for controlling the respective conducting states of the pullup and pulldown transistor elements. The collector of the secondary phase splitter transistor element is coupled in a supplemental circuit which can have a variable load without direct connection to the pullup transistor element and output. A low impedance current sourcing active transistor element is coupled in emitter follower configuration at the collector node of the secondary phase splitter transistor element for supplying mirroring current through the emitter of the secondary phase splitter transistor element to reduce current hogging at the dual phase splitter transistor elements.

Abstract: A transient voltage difference circuit is coupled into a TTL current sinking output circuit for transient performance enhancement during transition from high to low level potential at the output. The TTL output circuit includes a pulldown transistor element for sinking current from an output node to low potential, a base drive transistor for driving the base of a current sinking pulldown transistor element, an input base node of the base drive transistor coupled to receive input signals of high and low level potential, and a voltage clamp network coupled between the input base node and low potential for maintaining a potential level at the input base node sufficient to turn on the base drive transistor. An RC network is coupled between the input base node and low potential.

Abstract: A level and edge sensitive input circuit can recognize a variety of types of input signals on an input line and provide a standard digital logic output for use within the equipment. The input circuit is formed from a bias circuit, two comparators, and a memory bit. The bias circuit applies a bias voltage to the input line. A first comparator inverts the state of the memory bit when the input signals are an increment above the bias voltage. The second comparator clears the state of the memory bit when the input signals are an increment below the bias voltage. In this way, the memory bit cycles through states which provide the desired output signals for use within the equipment.

Abstract: A TTL to ECL/CML translator circuit delivers differential or complementary ECL logic output signals in response to TTL input signals with voltage gain, small output voltage swing and with a narrow transition region. The TTL input circuit is coupled to a current mirror circuit with first and second current mirror branch circuits. A differential amplifier gate circuit with differential amplifier first and second gate transistor elements co-acts with the current mirror circuit. The second current mirror branch circuit also constitutes the differential amplifier first gate transistor element. A threshold clamp circuit applies a threshold voltage level at the base node of the differential amplifier second gate transistor element thereby establishing a TTL input threshold at the threshold voltage level. First and second ECL output circuits are coupled to the collector nodes of the differential amplifier first and second gate transistor elements for delivering complementary ECL output signals.

Abstract: A pseudo-rail circuit is coupled between the differential output gate or buffer of an emitter coupled logic or current mode logic (ECL/CML) circuit and the high potential level power rail. The pseudo-rail circuit provides a pseudo-rail node. A first clamp circuit is coupled to the pseudo-rail node for clamping the pseudo-rail node at a first potential level in response to a first control signal. A second clamp circuit is coupled to the pseudo-rail node for clamping at a second potential level in response to a second control signal. A clamp switching circuit alternately applies the first and second clamp circuits to the pseudo-rail node in response to the control signals. As a cutoff driver circuit, the first clamp circuit of the pseudo-rail circuit applies the high potential level of the power rail to the pseudo-rail node. The second claim circuit pulls down the pseudo-rail node to hold the output of the differential output gate in the cutoff state.

Abstract: An emitter follower current switch circuit is provided for emitter coupled logic or current mode logic (ECL/CML) circuits having output buffer emitter follower transistor elements which source true and complementary output signals of high and low potential to respective true and complementary outputs of the ECL/CML gate. The emitter follower current switch circuit effectively disconnects the output current sink from and ECL/CML gate output and corresponding output buffer emitter follower transistor element when the corresponding output is at high potential. At each output a current switch transistor element is coupled between the respective output buffer emitter follower transistor element and the output current sink. A control circuit controls the conducting state of the current switch transistor element so that it is on (conducting) or off (non-conducting) for corresponding output signals of low and high potential respectively.