Abstract: An input stage of an operational amplifier uses current sources to allow first and second differential input transistor pairs to operate near the power supply rails. The output stage of the operational amplifier also operates within a saturation potential of the power supply rails. The first differential input transistor pair operates when the input signal is less than a predetermined threshold, while the second differential input transistor pair operates when the input signal is greater than the predetermined threshold. A detection circuit at the input terminals prevents phase inversion of the output signal should the inputs be driven beyond the power supply rails. A current cancellation circuit removes current variation induced by voltage changes at the output of the input stage and provides high gain and low input offset voltage.

Abstract: A current mirror having an input and an output, comprises a diode coupled to the input to which an input current is supplied for providing a bias potential thereacross; an output transistor having an emitter, base and collector, said base and said emitter being coupled respectively across said diode and said collector being coupled to the output, said output transistor being responsive to said diode means for providing an output current the magnitude of which is proportional to said input current; and a compensation circuit coupled to said base of said output transistor and being responsive thereto for producing an output current that is injected at the input of the current mirror for cancelling base current errors caused by the base current of said output transistor.

Abstract: A detection circuit including a first and second sensing circuits detects the presence of load current provided by a utilization circuit to which the detection circuit is coupled to provide an output current that is proportional to the load current. A fraction of the load current that is sourced from the utilization circuit flows through the first sensing circuit the latter of which then provides an output current proportional to the fractional load current. Similarly, a fraction of load current that is sunk by the utilization circuit flows through the second sensing means which provides an output current proportional to the fractional load current.

Abstract: An amplifier having an input and output stage for providing drive current to a load coupled thereto includes circuitry that senses when an input signal is applied to the amplifier and is responsive thereto for providing an enabling signal at an output thereof and current regulator circuitry that supplies a low drain current to bias the stages when the amplifier is in a quiescent operating mode absent an applied input signal and that is responsive to the enabling signal for increasing the current supplied to the stages to bias the same in a high bias drain current operating mode.

Abstract: A dectector circuit responsive to a current suppled to an input thereof provides an output signal when the magnitude of the current exceeds a predetermined threshold level includes a multi-collector transistor having a first one of its collectors connected to the base thereof and an emitter coupled to the input. A diode formed by a diode-connected transistor is coupled to the first collector of the multi-collector transistor. A second transistor is provided having its collector coupled to the second collector of the multi-collector transistor, a base coupled to the first collector and an emitter which is coupled to a pair of series connected resistors. The second transistor is operated at a lower current density than the diode-connected transistor such that the former operates in a saturated condition until such time that the input current exceeds the threshold level to produce the output signal.

Abstract: An active integrated termination circuit for providing a predetermined impedance at an output includes first and second resistors each having one end of which is commonly connected to the output. A first switching element is coupled between the other end of the first resistor and a first power supply conductor and is responsive to control signals for selectively coupling and de-coupling the first resistor to the first power supply conductor. A second switching element is coupled between the other end of the second resistor and a second power supply conductor and is responsive to the control signals for selectively coupling and de-coupling the second resistor to the second power supply conductor. The first and second resistors are polycrystalline silicon resistors and are trimmed to predetermined values by pulsing a high current unilaterally therethrough.

Abstract: In an output stage of an operational amplifier comprising first and second NPN output transistors a circuit is coupled between the positive supply conductor and the collector of the first NPN transistor for providing a boosted base current drive thereto as a function of the load current sourced from the emitter of the first transistor to the output of the operational amplifier. The circuit senses the collector current flowing through the first transistor for increasing the base current drive thereto as the collector current increases.

Abstract: A method for trimming a diffused or implanted resistor located within an integrated circuit is disclosed. This technique for trimming a resistor requires the use of high current pulses and geometric shaped metal contacts. The current pulses react with the electropositive metal atoms in the thin film conductor and cause the metal atoms to migrate to another location, thus altering the value of the resistor by progressively decreasing the conductivity of the resistor.

Abstract: An operational amplifier of the type which includes first and second differentially coupled input transistors which cooperate with a current mirror circuit also includes a first and second RTMM resistors which may be individually trimmed to reduce input offset voltage. Each RTMM resistor is coupled from the power supply rail through first and second diodes respectively to the first and second input terminals. In this manner, signals appearing on the input terminals which exceed the rail voltage will cause currents to flow through the RTMM resistors thus reducing their resistance, and reducing offset voltage.

Abstract: In an operational amplifier having an input stage of the type wherein first and second differentially coupled transistors cooperate with a current mirror circuit, an output transistor is provided having a compensation capacitor coupled between its collector and the input stage. The gain bandwidth product is enhanced by coupling a positive feedback device (e.g. a capacitor) between a collector of the output transistor and the collector of the first input transistor.

Abstract: First and second resistors of a resistive network formed in a semiconductive substrate may be individually trimmed. The first and second resistive regions coupled at one end thereof have their other ends provided with metallic contacts. The resistive regions are disposed on the substrate such that current flowing from the first metallic contact to the second metallic contact through the first and second resistive regions causes the resistance of the first resistive region to be preferentially reduced. In contrast, current flowing from the second metallic contact to the first metallic contact through the first and second resistive regions causes the resistance of the second resistive region to be preferentially reduced. The resistive network is used in an operational amplifier circuit so as to permit the input offset voltage to be substantially reduced by selective trimming.

Abstract: An improved field effect transistor follower circuit includes a transistor having equivalent input capacitance C.sub..pi. and a field-effect-transistor which has a gate electrode coupled to a source of an input signal, a drain coupled to a source of supply voltage, and a source coupled to the base of the transistor. A feed forward capacitor is provided and coupled between the gate and source electrodes of the field effect transistor. An operational amplifier is also disclosed which utilizes junction field-effect-transistor followers including feed forward capacitors.

Abstract: A circuit for generating a reference current proportional over temperature to the pinch-off voltage of a first JFET includes second and third JFETS and first and second resistors. The second JFET has its gate coupled to its source and produces a current which drives the first JFET. Since the width-to-length ratio of the second JFET is greater than that of the first, a negative gate-to-source voltage of the first JFET is produced across the first resistor. The third JFET has a source coupled via the second resistor to the gate of the first JFET and has a gate coupled to the drain of the first JFET for setting the voltage thereat. The reference current appears at the drain of the third JFET.

Abstract: An operational amplifier includes a pair of differentially coupled PNP transistors driving a current mirror circuit. The base of the each of the transistors is coupled to the source of a JFET follower transistor each of which in turn has a gate coupled to one of the amplifier's inputs. First and second current sources are coupled to the source electrodes of each of the JFETs for the purpose of supplying a current thereto equal to that JFET's I.sub.DSS (its drain current when its gate and source are shorted).

Abstract: First and second resistors of a resistive network formed in a semiconductive substrate may be individually trimmed. The first and second resistive regions coupled at one end thereof have their other ends provided with metallic contacts. The resistive regions are disposed on the substrate such that current flowing from the first metallic contact to the second metallic contact through the first and second resistive regions causes the resistance of the first resistive region to be reduced. In contrast, current flowing from the second metallic contact to the first metallic contact through the first and second resistive regions causes the resistance of the second resistive region to be reduced.

Abstract: A method for trimming a diffused or implanted resistor located within an integrated circuit is disclosed. This technique for trimming a resistor requires the use of high current pulses and geometric shaped metal contacts. The current pulses react with the electropositive metal atoms in the thin film conductor and cause the metal atoms to migrate to another location, thus altering the value of the resistor by progressively decreasing the conductivity of the resistor. An operational amplifier circuit utilizing resistors trimmed by metal migration is also disclosed.

Abstract: A method for trimming a diffused or implanted resistor located within an integrated circuit is disclosed. This technique for trimming a resistor requires the use of high current pulses and geometric shaped metal contacts. The current pulses react with the electropositive metal atoms in the thin film conductor and cause the metal atoms to migrate to another location, thus altering the value of the resistor by progressively decreasing the conductivity of the resistor.

Abstract: An operational amplifier includes an input stage, an output stage including first, second and third NPN output transistors, and an intermediate stage. The output stage is driven by a thermal current having a positive temperature coefficient so as to keep the gain of the output stage substantially constant over temperature. Thus, the amplifiers Miller loop stability will also remain substantially constant over temperature.

Abstract: An operational amplifier includes an input stage, an output stage including first, second and third NPN output transistors, and an intermediate stage. The first NPN output transistor sources load current to an output terminal while the second and third output transistors sink load current therefrom. The output of the intermediate stage is coupled to the base of the third NPN transistor and, via a resistor, to the base of the second NPN transistor. A first Miller capacitor is coupled between the input of the intermediate stage and the amplifier's output terminal, and a second Miller capacitor is coupled between the base of the second NPN transistor and the output terminal.

Abstract: An operational amplifier includes an input stage, an output stage including first, second and third NPN output transistors, and an intermediate stage. The first NPN output transistor sources load current to an output terminal while the second and third output transistors sink load current therefrom. A first Miller capacitor is coupled between the input of the intermediate stage and the amplifier's output terminal. A second Miller capacitor is coupled between the base and collector terminals of the third NPN output transistor.