Abstract: A circuit is used to cancel the effects of leakage in resistive circuits. A resistive circuit is used to generate a reference signal. The resistive circuit is subject to leakage at high temperatures. A matching leakage generator is selected to have leakage characteristics that are similar to the leakage characteristics of the resistive circuit. The matching leakage generator is used to generate a representative leakage current that is similar to the leakage current that is undesirably present in the resistive circuit. The representative leakage current is mirrored by a current mirror circuit. The mirrored leakage current is used to cancel the effects of leakage in the resistive circuit. Canceling the leakage current improves the accuracy of the reference signal at higher temperatures. The reference signal accuracy at high temperatures is improved because the effects of leakage current (which are greater at higher temperatures) are cancelled by the mirrored leakage current.

Abstract: A preamplifier amplifies a differential signal from a magneto-resistive read head. The preamplifier is designed to maximize gain and minimize introduction of noise, while maintaining wide bandwidths and common mode rejection performance. The emitters of the differential amplifier are coupled together by a third transistor and a capacitor.

Abstract: A current switch receives a differential voltage. The differential voltage has one of first and second polarities. The current switch provides an output current at a first output if the differential voltage has the first polarity and provides the output current at a second output if the differential voltage has the second polarity. An input stage receives the differential voltage. First and second switches are coupled to the input stage, and a resistor is coupled between the first and second switches. A voltage differential is maintained across the resistor, which induces a current in the resistor. The first switch provides the current to the first output responsive to the differential voltage having the first polarity and the second switch provides the current to the second output responsive to the differential voltage having the second polarity.

Abstract: An integrated circuit power transistor, comprising an elongate, resistive, base region and an elongate emitter region formed in part of the base region to provide a base-emitter junction. The power transistor also includes a strip-like base connection formed in part of the base region. The base connection extends from a base terminal towards a remote end, and includes a junction-facing edge facing the base-emitter junction. The junction-facing edge is spaced from the base-emitter junction by a distance that decreases towards the remote end of the base connection. This sets the base side of the base-emitter junction to substantially the same voltage at all points along the length of the base-emitter junction despite an ohmic voltage drop in the base connection that increases towards the remote end of the base connection.

Abstract: A Voss-type electronic tone control circuit in which the output of an amplifier is connected to the circuit output. An input resistor interconnects the circuit input and the amplifier inverting input and a feedback resistor interconnects the amplifier output and inverting input. One end of a first resistor is switched between the circuit input and the amplifier output. A first capacitor is connected between the other end of the first resistor and ground. A second capacitor is connected between the other end of the first resistor and one end of a potentiometer, the other end of which is grounded. The potentiometer slider feeds the amplifier non-inverting input. The capacitance of the second capacitor is different from that of the first capacitor, which enables the resistance of the first resistor to be increased, and the resistance of the potentiometer to be reduced compared with a conventional circuit. Increasing the first resistor resistance reduces loading on the boost/cut switch.

Abstract: A Voss-type electronic tone control circuit in which the output of an amplifier is connected to the circuit output. An input resistor interconnects the circuit input and the amplifier inverting input and a feedback resistor interconnects the amplifier output and inverting input. One end of a first resistor is switched between the circuit input and the amplifier output. A first capacitor is connected between the other end of the first resistor and ground. A second capacitor is connected between the other end of the first resistor and one end of a potentiometer, the other end of which is grounded. The potentiometer slider feeds the amplifier non-inverting input. The capacitance of the second capacitor is different from that of the first capacitor, which enables the resistance of the first resistor to be increased, and the resistance of the potentiometer to be reduced compared with a conventional circuit. Increasing the first resistor resistance reduces loading on the boost/cut switch.

Abstract: ECL to TTL converter circuits are shown having current mirror loads which produce the required differential to single-ended conversion. Saturation is avoided in the current mirror by connecting a resistor between the collector and base the output transistor.

Abstract: An integrated circuit amplifier suitable for use in driving capacitive loads, including a differential amplifier first stage, a third stage and at least one second stage intermediate the first and second stages. A dominant pole capacitor provides a direct negative feedback path between the amplifier output and the output of the first stage so as to tend to oppose any signals present at the output thereby reducing the open loop output impedance of the amplifier. In a preferred embodiment, an isolation resistor is coupled between the first output and a further output and a further compensating capacitor is coupled between the first output and an inverting input to the amplifier so as to produce a zero in the frequency response of the amplifier so as to compensate for any pole in the frequency response of the amplifier caused by any capacitive load connected to the further output.