Abstract: An operational amplifier circuit includes: a first differential pair 20 of a first conductivity type having a first current branch and a second current branch; a second differential pair 22 of a second conductivity type having a first current branch and a second current branch; a first current mirroring device MP11 and MP26 coupled between the first branch of the first differential pair 20 and the second branch of the second differential pair 22 for combining the currents from these two branches; and a second current mirroring device. MN22 and MN24 coupled between the first branch of the second differential pair 22 and the second branch of the first differential pair 20 for combining the currents from these two branches.

Abstract: An operational amplifier circuit includes: a first differential pair 20 of a first conductivity type having a first current branch and a second current branch; a second differential pair 22 of a second conductivity type having a first current branch and a second current branch; a first current mirroring device MP11 and MP26 coupled between the first branch of the first differential pair 20 and the second branch of the second differential pair 22 for combining the currents from these two branches; and a second current mirroring device MN22 and M24 coupled between the first branch of the second differential pair 22 and the second branch of the first differential pair 20 for combining the currents from these two branches.

Abstract: A variable gain voltage signal amplifier is provided for incorporation in an automatic gain control circuit, such as for a disk drive. The variable gain voltage signal amplifier comprises: an amplifier including an inverting input voltage signal terminal and an output voltage signal terminal. The amplifier includes an input signal path coupled to the input voltage signal terminal and further includes a feedback signal path coupling between the input voltage signal terminal and the output voltage signal terminal. The input signal path comprises a capacitor coupled in series with a resistor, and the feedback signal path comprises a resistor. At least one of the resistors comprises an electronic signal-controlled resistor.

Abstract: An improved operational transconductance amplifier (OTA) for use in sample-and-hold circuits or the like requiring very low output leakage currents and equalized output current transients when the OTA is placed in stand-by (disabled.) The OTA has an output stage that is referenced to ground by having two darlington pairs with common collector outputs as the output for the OTA in a common base configuration such that when the OTA is disabled, any leakage paths from the output of the OTA are coupled to ground. Further, the OTA is compensated internally to equalize any current transient output when the OTA is placed in stand-by such that the integral of the current transient out of the OTA is substantially the same as the integral of the current transient into the OTA from the integrator. A sample-and-hold circuit is also described utilizing the improved OTA.