Analog Devices, Inc.
Techniques for measuring slew rate in current integrating phase interpolator

Abstract:

An apparatus is described and includes a current integrating phase interpolator core having a programmable bias current; an inverter circuit coupled to an output of the current integrating phase interpolator core for receiving a signal comprising a periodic sawtooth waveform therefrom; a digital-to-analog (D/A) converter for setting an input common mode voltage of the inverter circuit; a duty cycle measurement (DCM) circuit for measuring a duty cycle distortion (DCD) of a clock signal output from the inverter circuit; and a circuit for computing a difference between a first state of the DCD of the clock signal corresponding to the input common mode voltage of the inverter circuit being set to a high voltage and a second state of the DCD of the clock signal corresponding to the input common mode voltage of the inverter circuit being set to a low voltage.