Abstract: A phase interpolator generates a phase-interpolated output clock signal Z from two phase-offset input clock signals A and B, where the interpolation angle of the output clock is based on a weight value W. The phase interpolator has A-side and B-side circuitry, each having (1) an array of parallel current mirrors, (2) a block of parallel switches, where each switch is connected in series with a corresponding current mirror, and (3) an encoder that controls the corresponding switches based on the weight value W. The total current through the phase interpolator varies with interpolation angle, such that, for example, the variation in output amplitude with interpolation angle is reduced. In general, individual bit values in weight value W are not used to control individual switches for all interpolation angles.

Abstract: A circuit is described that generates multiple voltages each having a common reference point. The circuit uses a feedback control loop to generate a center voltage, a first voltage generator, and a second voltage generator. The first voltage generator generates a first high voltage related to the center voltage plus a first offset voltage and a first low voltage related to the center voltage minus the first offset voltage, where the first offset voltage is determined by a first control input to the first voltage generator. The second voltage generator generates a second high voltage related to the center voltage plus a second offset voltage and a second low voltage related to the center voltage minus the second offset voltage, where the second offset voltage is determined by a second control input to the second voltage reference generator. An example is also presented where the multiple voltage generator circuit is advantageously employed in a deserializer data acquisition system.

Abstract: Disclosed is a system and method for improving the linearity of a clock and data recovery (CDR) circuit. A data stream is received and the phase of a clock signal is adjusted using two interpolators. The data stream is then recovered using the clock signal.

Abstract: An amplifier having DC offset compensation includes at least one input node and a pair of differential output nodes, a biasing circuit coupled to the input node; and a plurality of current sources.

Abstract: A system for a backplane that employs i) an adjustment of positive-to-negative (P-N) driver skew of a transmit signal of a relatively high-speed differential driver to reduce far-end crosstalk, ii) a high-speed differential subtraction circuit combining a gain-adjusted replica of at least one transmit signal with a received signal to reduce near-end crosstalk, and iii) a phase-locked loop (PLL) synchronization circuit to align timing events between a set of near-end and far-end high-speed interfaces.

Abstract: Signal processing circuitry having parallel processing channels has clock-generation circuitry that generates (i) high-speed clock signals used to drive the channels and (ii) synchronization signals used to reset the processing of the channels. In one embodiment, the signal processing circuitry has multiple multiplexing channels arranged in one or more macrocells, each macrocell having one or more channels and a phase-locked loop (PLL) that generates a high-speed PLL clock signal and a synchronization signal for the macrocell's channels. Each channel has a counter that implements a state machine used to drive the multiplexing processing, where the state machine is reset to a specified state upon receipt of each synchronization pulse in the synchronization signal.

Abstract: The performance of a single-bit cell in a DAC is improved by decoupling the voltage swing across the load resistors from the output of the current steering device. This can be achieved by providing for a single-bit cell having a first load resistor R1 and a second load resistor R2, a current steering circuit, and a decoupling circuit operably coupled between the current steering circuit and the resistors R1, R2. The current steering circuit steers at least part of a current I1 through a circuit path towards either the first resistor R1 or the second resistor R2. The decoupling circuit decouples voltage swings across the load resistors R1, R2 from the current steering circuit.

Abstract: The performance of a single-bit cell in a DAC is improved by decoupling the voltage swing across the load resistors from the output of the current steering device. This can be achieved by providing for a single-bit cell having a first load resistor R1 and a second load resistor R2, a current steering circuit, and a decoupling circuit operably coupled between the current steering circuit and the resistors R1, R2. The current steering circuit steers at least part of a current I1 through a circuit path towards either the first resistor R1 or the second resistor R2. The decoupling circuit decouples voltage swings across the load resistors R1, R2 from the current steering circuit.