Abstract: The input stage of the fully differential amplifier output stage is configured in a differential pair configuration with a tail current. The tail current is divided between two legs of the input stage and is higher in the leg that has the higher of the two input voltage levels (in or inb). The devices in each leg of the fully differential amplifier output stage may be cascoded to avoid electrical voltage overstress. The top device in each leg of the differential input stage may be coupled in a diode configuration and is utilized to mirror the current into another NMOS current mirror as well as to a PMOS output device. The gate of the PMOS output devices are connected in a cross-coupled configuration. The NMOS current mirrors are utilized to mirror the current into the NMOS output devices in a non-cross-coupled configuration.

Abstract: A circuit and method are provided for generating a programmable clock signal VRCLK at a frequency of a reference signal VREF such that the phase of VRCLK in relation to the phase of VREF is variable. VREF and VRCLK are each coupled to a frequency comparing circuit which computes their respective frequencies. The frequency comparing circuit subtracts the respective frequencies of VREF and VRCLK to produce a frequency adjusting signal VFREQ which corresponds to the difference in the frequencies of VREF and VRCLK. VFREQ is used to adjust the frequency of VRCLK.