Systems and methods for frequency reference generation are described. In an embodiment, a frequency reference circuit, includes: a bandgap proportional to temperature (PTAT) generator circuit that generates a bandgap PTAT current; a resistor complementary to temperature (CTAT) generator circuit that generates a resistor CTAT current; an adder that adds the PTAT current and the CTAT current to generate a constant current I.sub.cons; a switched-resistor (switched-R) circuit that receives the constant current I.sub.cons and a previously generated output clock and generates an output; a bandgap voltage reference generator circuit that generates a bandgap voltage V.sub.BG; an integrator circuit that receives the output of the switched-R circuit and the bandgap voltage V.sub.BG and generates an output; and a voltage-controlled oscillator (VCO) circuit that receives the output of the integrator circuit and generates a frequency reference.

Spectrally-efficient digital logic (SEDL) techniques implement spectrally-efficient pulses (e.g., Gaussian-shaped pulses) in lieu of conventional square waveforms to improve electromagnetic, radio frequency, and other unwanted emissions. The SEDL techniques can be used for analog-to-digital converters (ADC) and digital-to-analog converters (DAC). An ADC circuit comprises a plurality of comparators configured to receive an analog input signal and compare the analog input signal to a predetermined reference signal, an encoder, and a spectrally-efficient circuit. A DAC circuit includes an integrator circuit, a clocked comparator circuit, a pulse generator, and a combiner circuit. The clocked comparator circuit receives the logic state of each SEDL pulse. The pulse generator receives the logic state and generates a scaled SEDL pulse for each input SEDL pulse. A combiner circuit combines the outputs from the pulse generator and determines analog value corresponding to the input values.

An input driven self-clocked dynamic comparator, and associated systems and methods are described herein. In one embodiment, self-clocked dynamic comparator, includes a latch configured to receive an input voltage (VIN), a reference voltage (VREF) and a clocking (CLKsf) signal, and configured to output a first rail-to-rail output (OUT+) signal and a second rail-to-rail output (OUT−) signal. The self-clocked dynamic comparator also includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF. The self-clocked dynamic comparator further includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF, and a logic gate configured to receive the TRI signal and one of the OUT+ signal and OUT− signal, and configured to output the CLKsf signal. The cycles of the CLKsf signal cause the latch to dissipate energy.

An integrated circuit can include latched comparator circuitry. The latched comparator circuitry may include first and second input transistors configured to receive an input signal, first and second cross-coupled inverting circuits, reset transistors, and a current pulse generator. The first and second inverting circuits may each include a pull-up transistor and a pull-down transistor. The first input transistor may be coupled between the pull-up and pull-down transistors in the first inverting circuit. The second input transistor may be coupled between the pull-up and pull-down transistors in the second inverting circuit. The reset transistors may be coupled in parallel with the pull-up transistors and may receive a clock signal. The current pulse generator may receive the clock signal and generate current pulse signals in response to detecting edges in the clock signal. Latched comparator circuitry configured and operated in this way can provide reduced clock kickback noise.

Spectrally-efficient digital logic (SEDL) techniques implement spectrally-efficient pulses (e.g., Gaussian-shaped pulses) in lieu of conventional square waveforms to improve electromagnetic, radio frequency, and other unwanted emissions. The SEDL techniques can be used for analog-to-digital converters (ADC) and digital-to-analog converters (DAC). An ADC circuit comprises a plurality of comparators configured to receive an analog input signal and compare the analog input signal to a predetermined reference signal, an encoder, and a spectrally-efficient circuit. A DAC circuit includes an integrator circuit, a clocked comparator circuit, a pulse generator, and a combiner circuit. The clocked comparator circuit receives the logic state of each SEDL pulse. The pulse generator receives the logic state and generates a scaled SEDL pulse for each input SEDL pulse. A combiner circuit combines the outputs from the pulse generator and determines analog value corresponding to the input values.

An input clock buffer, comprising: a first capacitor; a second capacitor; a first amplifier, configured to generate a first output signal, comprising input terminals coupled to the first capacitor and the second capacitor, wherein the first capacitor and the second capacitor receives a differential input signal; a second amplifier, configured to generate a second output signal according to the differential input signal; a frequency detection circuit, configured to generate a frequency detection signal according to a frequency of the differential input signal; and a switch, located between an output of the first amplifier and an output of the second amplifier, configured to turn on and turn off according to the frequency detection signal.

Spectrally-efficient digital logic (SEDL) techniques implement spectrally-efficient pulses (e.g., Gaussian-shaped pulses) in lieu of conventional square waveforms to improve electromagnetic, radio frequency, and other unwanted emissions. The SEDL techniques can be used for analog-to-digital converters (ADC) and digital-to-analog converters (DAC). An ADC circuit comprises a plurality of comparators configured to receive an analog input signal and compare the analog input signal to a predetermined reference signal, an encoder, and a spectrally-efficient circuit. A DAC circuit includes an integrator circuit, a clocked comparator circuit, a pulse generator, and a combiner circuit. The clocked comparator circuit receives the logic state of each SEDL pulse. The pulse generator receives the logic state and generates a scaled SEDL pulse for each input SEDL pulse. A combiner circuit combines the outputs from the pulse generator and determines analog value corresponding to the input values.

Spectrally-efficient digital logic (SEDL) techniques implement spectrally-efficient pulses (e.g., Gaussian-shaped pulses) in lieu of conventional square waveforms to improve electromagnetic, radio frequency, and other unwanted emissions. The SEDL techniques can be used for analog-to-digital converters (ADC) and digital-to-analog converters (DAC). An ADC circuit comprises a plurality of comparators configured to receive an analog input signal and compare the analog input signal to a predetermined reference signal, an encoder, and a spectrally-efficient circuit. A DAC circuit includes an integrator circuit, a clocked comparator circuit, a pulse generator, and a combiner circuit. The clocked comparator circuit receives the logic state of each SEDL pulse. The pulse generator receives the logic state and generates a scaled SEDL pulse for each input SEDL pulse. A combiner circuit combines the outputs from the pulse generator and determines analog value corresponding to the input values.

An input clock buffer, comprising: a first capacitor; a second capacitor; a first amplifier, configured to generate a first output signal, comprising input terminals coupled to the first capacitor and the second capacitor, wherein the first capacitor and the second capacitor receives a differential input signal; a second amplifier, configured to generate a second output signal according to the differential input signal; a frequency detection circuit, configured to generate a frequency detection signal according to a frequency of the differential input signal; and a switch, located between an output of the first amplifier and an output of the second amplifier, configured to turn on and turn off according to the frequency detection signal.

An input driven self-clocked dynamic comparator, and associated systems and methods are described herein. In one embodiment, self-clocked dynamic comparator, includes a latch configured to receive an input voltage (VIN), a reference voltage (VREF) and a clocking (CLKsf) signal, and configured to output a first rail-to-rail output (OUT+) signal and a second rail-to-rail output (OUT) signal. The self-clocked dynamic comparator also includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF. The self-clocked dynamic comparator further includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF, and a logic gate configured to receive the TRI signal and one of the OUT+ signal and OUT signal, and configured to output the CLKsf signal. The cycles of the CLKsf signal cause the latch to dissipate energy.