A bandpass filter configured to receive a temporally modulated periodic input signal Vin(t), and to deliver an output signal Vout(t), and includes, in combination: a phase comparator configured to receive, on a first input, the temporally modulated periodic input signal Vin(t) as first signal, and to generate an output signal with a variable duty cycle; coupled to an injection-locked oscillator configured to receive as input, the output signal from the phase comparator, and to generate a signal Vr(t) that is phase-offset with respect to the output signal from the phase comparator; the phase-offset signal being applied to a second input of the phase comparator as second input signal; and the output signal from the phase comparator being the output signal Vout(t) from the bandpass filter and being representative of the phase difference between the two input signals Vin(t) and Vr(t).

According to one embodiment, a digital isolator includes a first metal portion, a first insulating portion, a second metal portion, a third metal portion, and a first layer. The first insulating portion is provided on the first metal portion. The second metal portion is provided on the first insulating portion. The third metal portion includes first, second, and third portions. The first portion is provided around the first metal portion in a direction perpendicular to a first direction. The second portion is provided on a portion of the first portion with a first conductive layer interposed. The third portion is provided on the second portion and provided around the second metal portion in the perpendicular direction. The first layer contacts the first conductive layer and an other portion of the first portion and is provided around a bottom portion of the second portion.

According to one embodiment, a digital isolator includes a first metal portion, a first insulating portion, a second metal portion, a third metal portion, and a first layer. The first insulating portion is provided on the first metal portion. The second metal portion is provided on the first insulating portion. The third metal portion includes first, second, and third portions. The first portion is provided around the first metal portion in a direction perpendicular to a first direction. The second portion is provided on a portion of the first portion with a first conductive layer interposed. The third portion is provided on the second portion and provided around the second metal portion in the perpendicular direction. The first layer contacts the first conductive layer and an other portion of the first portion and is provided around a bottom portion of the second portion.

According to one embodiment, a digital isolator includes a first metal portion, a first insulating portion, a second metal portion, a third metal portion, and a first layer. The first insulating portion is provided on the first metal portion. The second metal portion is provided on the first insulating portion. The third metal portion includes first, second, and third portions. The first portion is provided around the first metal portion in a direction perpendicular to a first direction. The second portion is provided on a portion of the first portion with a first conductive layer interposed. The third portion is provided on the second portion and provided around the second metal portion in the perpendicular direction. The first layer contacts the first conductive layer and an other portion of the first portion and is provided around a bottom portion of the second portion.

According to one embodiment, a digital isolator includes a first metal portion, a first insulating portion, a second metal portion, a third metal portion, and a first layer. The first insulating portion is provided on the first metal portion. The second metal portion is provided on the first insulating portion. The third metal portion includes first, second, and third portions. The first portion is provided around the first metal portion in a direction perpendicular to a first direction. The second portion is provided on a portion of the first portion with a first conductive layer interposed. The third portion is provided on the second portion and provided around the second metal portion in the perpendicular direction. The first layer contacts the first conductive layer and an other portion of the first portion and is provided around a bottom portion of the second portion.

Techniques are described for accurate tracking of a radiofrequency (RF) carrier for amplitude-modulated signals in unstable reference clock environments. For example, some embodiments operate in context of clock circuits in devices configured for near-field communication (NFC) card emulation (CE) mode. The clock circuits seek to generate an internal clocking signal by tracking a clock reference, such as an RF carrier. In some cases, the clock reference can unpredictably become unreliable for periods of time, during which continued tracking of the unreliable clock reference can yield appreciable frequency and phase errors in the generated internal clocking signal. Embodiments implement phase delta detection with time limiting to limit the magnitude of such errors in the internal clocking signal introduced while tracking an unreliable clock reference. For example, embodiments force gating of phase tracking signals to limit their duration, thereby limiting impacts of those phase tracking signals on the clock circuit output.

A regenerative selective logarithmic detector amplifier (LDA) can have integrated FM demodulation capabilities. It can receive a wired or wireless FM modulated signal and amplify or demodulate it with high sensitivity, high skirt ratio and minimized noise when compared to the prior art. When used in conjunction with other circuits such as a PLL or mixer, it can improve interference rejection and frequency selectivity and be locked on a precise channel in frequency and phase. The LDA produces intermittent oscillations that are self-quenched when reaching a given threshold. It also embeds the circuitry to perform direct FM discrimination. FM demodulation process is completed by a simple analog or digital frequency to voltage converter. This plus the fact that the instantaneous regeneration gain is low-medium permit to detect signals of small amplitudes buried in the noise.

A regenerative selective logarithmic detector amplifier (LDA) can have integrated FM demodulation capabilities. It can receive a wired or wireless FM modulated signal and amplify or demodulate it with high sensitivity, high skirt ratio and minimized noise when compared to the prior art. When used in conjunction with other circuits such as a PLL or mixer, it can improve interference rejection and frequency selectivity and be locked on a precise channel in frequency and phase. The LDA produces intermittent oscillations that are self-quenched when reaching a given threshold. It also embeds the circuitry to perform direct FM discrimination. FM demodulation process is completed by a simple analog or digital frequency to voltage converter. This plus the fact that the instantaneous regeneration gain is low-medium permit to detect signals of small amplitudes buried in the noise.

Several circuits and methods for transferring an input data signal in a digital isolator are disclosed. In an embodiment, the digital isolator includes an isolation element, input circuit, and output circuit. The isolation element includes at least one input node and at least one output node, the input circuit is electronically coupled to the input node and generates modulated differential data signals based on modulating the input data signal on a carrier signal. The input circuit operates using a first supply voltage with respect to a first ground. The output circuit is electronically coupled to the output node to receive the modulated differential data signals, operates using a second supply voltage with respect to a second ground and includes a frequency-shift keying demodulator configured to generate a demodulated data signal in response to detection of presence of the carrier signal. The output circuit further generates an output data signal.

Several circuits and methods for transferring an input data signal in a digital isolator are disclosed. In an embodiment, the digital isolator includes an isolation element, input circuit, and output circuit. The isolation element includes at least one input node and at least one output node, the input circuit is electronically coupled to the input node and generates modulated differential data signals based on modulating the input data signal on a carrier signal. The input circuit operates using a first supply voltage with respect to a first ground. The output circuit is electronically coupled to the output node to receive the modulated differential data signals, operates using a second supply voltage with respect to a second ground and includes a frequency-shift keying demodulator configured to generate a demodulated data signal in response to detection of presence of the carrier signal. The output circuit further generates an output data signal.