Abstract: Methods and apparatus are disclosed for calibrating summing amplifiers based on current integration. For example, apparatus for calibrating output voltage levels of a current-integrating summing amplifier includes the following components. A duplicate integrator circuit is provided, wherein the duplicate integrator circuit replicates an integrator circuit of the current-integrating summing amplifier. A comparing circuit, coupled to the duplicate integrator circuit, is provided for comparing at least one output voltage level generated by the duplicate integrator circuit with a reference voltage level.

Abstract: A method for implementing phase rotator circuits and phase rotator circuit of the invention includes a polyphase filter network to create a quadrature phase version of the input signal. The polyphase filter network is partitioned into a first part that is physically isolated from the phase rotator circuit and a second part that is embedded in the phase rotator circuit. The second part of the polyphase filter is coupled to the first part of the polyphase filter by a high-pass equalizing buffer stage. The second part of the polyphase filter is coupled to the phase rotator circuit by a bandlimiting buffer stage.

Abstract: A decision feedback equalizer (DFE) and method include summer circuits configured to add a dynamic feedback tap to a received input to provide a sum and to add a speculative static tap to the sum. Sense amplifiers are configured to receive outputs of the summer circuits and evaluate the outputs of the summer circuits in accordance with a clock signal. A passgate multiplexer is configured to receive outputs from sense amplifiers wherein the multiplexer is clock-gated for isolation of subsequent circuitry from the outputs of the sense amplifiers during a precharge period. A gating circuit is configured to perform gating of a select signal output from a second circuit portion with a clock signal and to enable the isolation of the subsequent circuitry by the multiplexer during the precharge period.

Abstract: Methods and apparatus are disclosed for calibrating summing amplifiers based on current integration. For example, apparatus for calibrating output voltage levels of a current-integrating summing amplifier includes the following components. A duplicate integrator circuit is provided, wherein the duplicate integrator circuit replicates an integrator circuit of the current-integrating summing amplifier. A comparing circuit, coupled to the duplicate integrator circuit, is provided for comparing at least one output voltage level generated by the duplicate integrator circuit with a reference voltage level.

Abstract: A method for implementing phase rotator circuits and phase rotator circuit of the invention includes a polyphase filter network to create a quadrature phase version of the input signal. The polyphase filter network is partitioned into a first part that is physically isolated from the phase rotator circuit and a second part that is embedded in the phase rotator circuit. The second part of the polyphase filter is coupled to the first part of the polyphase filter by a high-pass equalizing buffer stage. The second part of the polyphase filter is coupled to the phase rotator circuit by a bandlimiting buffer stage.