Abstract: A method and apparatus for removing low frequency noise and any offsets common to a plurality of samples of a signal, for calibrating an offset level to be added to the signal to reference the signal to a desired reference level at an output of the apparatus, and for clamping an input voltage level to the apparatus to a desired voltage within an operating range of the apparatus. The apparatus includes a correlated double-sampling circuit which takes a first sample and a second sample of the analog signal, takes a difference between the first sample and the second sample to remove low frequency noise and any offsets common to both samples and which outputs a difference signal. In addition, the apparatus includes a black level correction circuit which adds an offset level to the difference signal to calibrate the offset level to be added to the difference signal so that the difference signal is at a desired reference level at an output of the apparatus.

Abstract: A fully differential operational amplifier includes first and second frequency dependent impedance dividers, preferably frequency dependent current dividers, each of which has an input, a noninverting output and an inverting output. A respective input is coupled to a differential input signal. The noninverting output of the first frequency dependent impedance divider is electrically coupled to the inverting output of the second frequency dependent impedance divider, and the noninverting output of the second impedance divider is electrically coupled to the inverting output of the first divider. A current feedback buffer electrically couples the noninverting output of a respective frequency dependent impedance divider to its associated input. The cross coupling and current feedback buffers provide positive feedback action which merges the inverting and noninverting differential signals as a function of frequency.

Abstract: An analog-to-digital converter utilizes both a successive approximation register and a current steering circuit within a digital-to-analog converter to achieve an improved conversion speed, and improved resolution for a predetermined amount of power. The current steering circuit, which is controlled by the successive approximation register, connects constant current sources to current source loads to produce a differential signal output. By steering current from the differential current source loads to the constant current sources, a signal difference resolves at the output of the digital-to-analog converter faster and with greater resolution.

Abstract: A voltage that is proportional to a differential input voltage is applied across two resistors. Each resistor produces a current that is proportional to the input voltage. The current from each resistor flows through an associated current mirror. Each current mirror produces a current equal to the current flowing through the associated resistor. The current produced by each current mirror becomes an output current that is proportional to the input voltage.