Abstract:
A phase interpolator implemented in an integrated circuit to generate a clock signal is described. The phase interpolator comprises a plurality of inputs coupled to receive a plurality of clock signals; a plurality of transistor pairs, each transistor pair having a first transistor coupled to a first output node and a second transistor coupled to a second output node, wherein a first clock signal associated with the transistor pair is coupled to a gate of the first transistor and an inverted first clock signal associated with the transistor pair is coupled to a gate of the second transistor; a first active inductor load coupled to the first output node; and a second active inductor load coupled to the second output node.
Abstract:
In an example, a phase-locked loop (PLL) circuit includes an error detector operable to generate an error signal; an oscillator operable to provide an output signal having an output frequency based on the error signal and a frequency band select signal, the output frequency being a frequency multiplier times a reference frequency; a frequency divider operable to divide the output frequency of the output signal to generate a feedback signal based on a divider control signal; a sigma-delta modulator (SDM) operable to generate the divider control signal based on inputs indicative of an integer value and a fractional value of the frequency multiplier, the SDM responsive to an order select signal operable to select an order of the SDM; and a state machine operable to, in an acquisition state, generate the frequency band select signal and set the order of the SDM.
Abstract:
Voltage-controlled oscillation (100) is described. In an apparatus therefor, an inductor (120) has a tap and has or is coupled to a positive-side output node (105) and a negative side output node (106). The tap is coupled to receive a first current. A coarse grain capacitor array (130) is coupled to the positive-side output node (105) and the negative side output node (106) and is coupled to respectively receive select signals (168). A varactor (140) is coupled to the positive-side output node (105) and the negative side output node (106) and is coupled to receive a control voltage (143). The varactor (140) includes MuGFETs (141, 142). A transconductance cell (150) is coupled to the positive- side output node (105) and the negative side output node (106), and the transconductance cell (150) has a common node (107). A frequency scaled resistor network (160) is coupled to the common node (107) and is coupled to receive the select signals (168) for a resistance for a path for a second current.
Abstract:
A tunable resonant circuit (102) includes first capacitors (104, 108, 216, 228, 232) and second capacitors (106, 1 10, 218, 230, 234) that provide a matched capacitance between first and second electrodes of the first and second capacitors. A deep-well arrangement includes a first well (320, 326) disposed within a second well (322, 328) in a substrate (324). The first and second capacitors are each disposed on the first well. Two channel electrodes of a first transistor (120, 130) are respectively coupled to the second electrode (1 14, 304) of the first capacitor and the second electrode (1 18, 308) of the second capacitor. Two channel electrodes of a second transistor (122, 132) are respectively coupled to the second electrode of the first capacitor and to ground. Two channel electrodes of the third transistor (124, 134) are respectively coupled to the second electrode of the second capacitor and to ground. The gate electrodes (226, 314) of the first, second, and third transistors are responsive to a tuning signal (126, 136), and an inductor (144, 202) is coupled between the first electrodes (1 12, 1 16, 302, 306) of the first and second capacitors.