Abstract: A driver circuit transmits a signal generated by a signal level generation circuit to a circuit to be measured by transmitting the signal to a output buffer circuit via a circuit (prebuffer circuit) that drives the output buffer circuit and causing the output buffer circuit to drive a transmission line. The driver circuit includes the prebuffer circuit and a replica buffer circuit formed by imitating the prebuffer circuit. The prebuffer circuit and the replica buffer circuit are disposed in parallel. The driver circuit temporarily increases input bias current to be supplied to output-stage transistors of the output buffer circuit on the basis of output current of the replica buffer circuit during transition of an input or output signal.

Abstract: A driver circuit transmits a signal generated by a signal level generation circuit to a circuit to be measured by transmitting the signal to a output buffer circuit via a circuit (prebuffer circuit) that drives the output buffer circuit and causing the output buffer circuit to drive a transmission line. The driver circuit includes the prebuffer circuit and a replica buffer circuit formed by imitating the prebuffer circuit. The prebuffer circuit and the replica buffer circuit are disposed in parallel. The driver circuit temporarily increases input bias current to be supplied to output-stage transistors of the output buffer circuit on the basis of output current of the replica buffer circuit during transition of an input or output signal.

Abstract: A very-small-signal amplifier is capable of amplifying very small signals with high sensitivity up to high frequencies while simplifying the circuit, and a magnetic disk storage apparatus realizes a reading operation over a wide band up to high frequencies with high sensitivity. The signal amplifier is a modified differential circuit including a first transistor of a first conductivity type and a second transistor of a second conductivity type each having a control terminal, a terminal of the input side and a terminal of the output side. The terminals on the input side are connected in common, and a current corresponding to the voltage difference across the control terminals is allowed to flow. A very small voltage signal generated by an input signal source is applied to the control terminal of said first transistor. A bias voltage is applied to the control terminal of the second transistor.

Abstract: A very-small-signal amplifier is capable of amplifying very small signals with high sensitivity up to high frequencies while simplifying the circuit, and a magnetic disk storage apparatus realizes a reading operation over a wide band up to high frequencies with high sensitivity. The signal amplifier is a modified differential circuit including a first transistor of a first conductivity type and a second transistor of a second conductivity type each having a control terminal, a terminal of the input side and a terminal of the output side. The terminals on the input side are connected in common, and a current corresponding to the voltage difference across the control terminals is allowed to flow. A very small voltage signal generated by an input signal source is applied to the control terminal of said first transistor. A bias voltage is applied to the control terminal of the second transistor.

Abstract: A very-small-signal amplifier is capable of amplifying very small signals with high sensitivity up to high frequencies while simplifying the circuit, and a magnetic disk storage apparatus realizes a reading operation over a wide band up to high frequencies with high sensitivity. The signal amplifier is a modified differential circuit including a first transistor of a first conductivity type and a second transistor of a second conductivity type each having a control terminal, a terminal of the input side and a terminal of the output side. The terminals on the input side are connected in common, and a current corresponding to the voltage difference across the control terminals is allowed to flow. A very small voltage signal generated by an input signal source is applied to the control terminal of said first transistor. A bias voltage is applied to the control terminal of the second transistor.