Hybrid phase interpolator with unified blender and eye-surf circuit

A receiver circuit, comprising:

• a phase interpolator for processing a clock signal to generate a first plurality of phase-shifted clock signals and a second plurality of phase-shifted clock signals;
• and
• a unified blender and eye-surf circuit comprising:
• a first signal path to receive the first plurality of phase-shifted clock signals, the first signal path:
• in a blender mode, blending phases of two phase-shifted clock signals of the first plurality of phase-shifted clock signals in a fixed ratio to generate a first blended clock signal;
• and
• in an eye-surf test mode, creating variable phase offsets as weighted combinations of sets of two phase-shifted clock signals of the first plurality of phase-shifted clock signals to generate the first blended clock signal;
• and
• a second signal path to receive the second plurality of phase-shifted clock signals, the second signal path:
• in the blender mode, blending phases of two phase-shifted clock signals of the second plurality of phase-shifted clock signals in a fixed ratio to generate a second blended clock signal;
• and
• in the eye-surf test mode, creating variable phase offsets as weighted combinations of sets of two phase-shifted clock signals of the second plurality of phase-shifted clock signals to generate the second blended clock signal.

A method comprising:

• operating a first signal path of a receiver in a blender mode to blend phases of two phase-shifted clock signals of a first plurality of phase-shifted clock signals in a fixed ratio to generate a first blended clock signal;
• operating a second signal path of the receiver in the blender mode to blend phases of two phase-shifted clock signals of a second plurality of phase-shifted clock signals in a fixed ratio to generate a second blended clock signal;
• using the first blended clock signal and the second blended clock signal to sample a data signal of the receiver;
• operating the first signal path in an eye-surf test mode to create variable phase offsets as weighted combinations of sets of two phase-shifted clock signals of the first plurality of phase-shifted clock signals to generate the first blended clock signal;
• operating a second signal path in the eye-surf test mode to create variable phase offsets as weighted combinations of sets of two phase-shifted clock signals of the second plurality of phase-shifted clock signals to generate the second blended clock signal;
• and
• using the first blended clock signal and the second blended clock signal to determine an eye-width margin of the receiver.