Abstract: An apparatus for scaling a load device with frequency in a phase interpolator can include an analog loop and a digital loop. The load device of the phase interpolator can include a transistor and a plurality of resistors selectively configured in parallel with the transistor. The analog loop controls a resistance of the transistor based on a voltage applied to a control terminal of the transistor. For instance, the analog loop can tune the resistance of a PMOS device by adjusting a voltage applied to the PMOS device's gate terminal. In addition, the analog loop can include a comparator to compare a voltage across the transistor to a reference voltage such that an optimal voltage is maintained for an output swing of the phase interpolator. The analog loop can also include a low pass filter coupled to an output of the comparator to define frequency stability and loop bandwidth of the analog loop.

Abstract: An apparatus for scaling a load device with frequency in a phase interpolator can include an analog loop and a digital loop. The load device of the phase interpolator can include a transistor and a plurality of resistors selectively configured in parallel with the transistor. The analog loop controls a resistance of the transistor based on a voltage applied to a control terminal of the transistor. For instance, the analog loop can tune the resistance of a PMOS device by adjusting a voltage applied to the PMOS device's gate terminal. In addition, the analog loop can include a comparator to compare a voltage across the transistor to a reference voltage such that an optimal voltage is maintained for an output swing of the phase interpolator. The analog loop can also include a low pass filter coupled to an output of the comparator to define frequency stability and loop bandwidth of the analog loop.

Abstract: An architecture to compensate for the non-linear effects of magnetic media, such as magnetic disk drives, that distorts data transitions when data is written to the media and in which the non-linear distortion is data sequence dependent. In one technique a circuit is used to alter the data transitions to cancel the effects of the transition distortion. The circuit employs selected delays that that based on the data sequence to adjust the transition edge of bits of the data to provide the pre-compensation before data is written to the disk.