Abstract: The trend in wireless communication receivers is to capture more and more bandwidth to support higher throughput, and to directly sample the radio frequency (RF) signal to enable re-configurability and lower cost. Other applications like instrumentation also demand the ability to digitize wide bandwidth RF signals. These applications benefit from input circuitry which can perform well with high speed, wide bandwidth RF signals. An input buffer and bootstrapped switch are designed to service such applications, and can be implemented in 28 nm complementary metal-oxide (CMOS) technology.

Abstract: Isolators for providing electrical isolation between two circuits operating at different voltages are described, in which multiple semiconductor dies including the isolator components and the components of the two circuits are stacked on top of each other to provide a laterally-compact arrangement. An isolation barrier electrically separates the two circuits, and the isolator may provide a communication channel for transfer of information and/or power between the two circuits. The isolator may be included in an integrated device having a stacked die configuration where a first semiconductor die includes the isolator and components of the first of the two circuits, and a second semiconductor die positioned over the first semiconductor die includes components of the second of the two circuits. Two components of the isolator may be formed in separate layers of the first semiconductor die.

Abstract: Apparatus and methods for a difference amplifier are provided. In certain examples, the difference amplifier can provide high common mode rejection without differential signal attenuation. In an example, a difference amplifier circuit can include first and second amplifiers, first and second buffer amplifiers, a first feedback voltage divider coupled between an output of the first buffer amplifier and an output of the second amplifier, and a second feedback voltage divider coupled between an output of the second buffer amplifier and an output of the first amplifier.

Abstract: Sampled analog data are transferred between sampled analog circuits operating on respective local phase clocks which are triggered by a master clock. In response to a first (DATA READY) signal from an upstream sampled analog circuit, the sampled analog data are transferred from an upstream sampled analog circuit to a data transfer circuit. In response to a second (READY FOR DATA) signal from a downstream sampled analog circuit, the sampled data are transferred from the data transfer circuit to the downstream sampled analog circuit. The sampled data are delayed in the data transfer circuit for at least one master clock cycle when the second signal from the downstream sampled analog circuit is received before the first signal is received from the upstream sampled analog circuit.

Abstract: A single photo mask can be used to define the three critical layers for the piezoelectric MEMS device, specifically the top electrode layer, the piezoelectric material layer, and the bottom electrode layer. Using a single photo mask removes the misalignment source caused by using multiple photo masks. Furthermore, in certain exemplary embodiments, all electrical interconnects use underpass interconnect. This simplifies the process for defining the device electrodes and the process sequence for achieving self-alignment between the piezoelectric element and the top and bottom electrodes. This self-alignment is achieved by using an oxide hard mask to etch the critical region of the top electrode, the piezoelectric material, and the bottom electrode with one mask and different etch chemistries depending on the layer being etched.

Abstract: Various techniques that can provide a capability to background calibrate ADC linearity error, e.g., due to capacitor mismatch drift and other parameter drift, during normal ADC operation in which analog-to-digital signal conversions are ongoing. A method can include grouping capacitors of an ADC into multiple clusters and calibrating under an arbitrary signal condition. To quickly converge the calibration result, the same arbitrary signal can be converted twice, and the capacitor(s) being calibrated can be modulated after first conversion. The difference between the results of the first and second conversions can contain the error information that can be used for calibration, and the signal component can be removed by this process. These techniques can provide improved linearity at 20-bit level and beyond.

Abstract: Delta-sigma modulators do not handle overload well, and often become unstable if the input goes beyond the full-scale range of the modulator. To provide overload protection, an improved technique embeds an overload detector in the delta sigma modulator. When an overload condition is detected, coefficient(s) of the delta sigma modulator is adjusted to accommodate for the overloaded input. The improved technique advantageously allows the delta sigma modulator to handle overload gracefully without reset, and offers greater dynamic range at reduced resolution. Furthermore, the coefficient(s) of the delta sigma modulator can be adjusted in such a way to ensure the noise transfer function is not affected.

Abstract: A MEMS switch device including: a substrate layer; an insulating layer formed over the substrate layer; and a MEMS switch module having a plurality of contacts formed on the surface of the insulating layer, wherein the insulating layer includes a number of conductive pathways formed within the insulating layer, the conductive pathways being configured to interconnect selected contacts of the MEMS switch module.

Abstract: A method of reducing the noise from a transmitter at an associated receiver is disclosed. Noise contributions in active channels are identified and used to update a shared noise cancellation filter. Excluding signals from inactive channels speeds up the filter convergence to a near optimal solution. Sharing a filter across multiple channels reduces component count and power consumption.

Abstract: A two-input amplifier is disclosed. The amplifier can include an amplification path for a first input signal that can have adjustable flatness or high-frequency peaking, and an amplification path for a second input that can be substantially independent of the frequency-shaping aspect of the first-input path. The first-input amplification path can include an operational amplifier as an active device and a plurality of passive elements for frequency shaping. The second-input amplification path can include a device that injects its output current into a node of the first path. The signals of the two paths can be combined and appear substantially independently of each other at the output of the amplifier.

Abstract: An analog-to-digital converter (ADC) is a device that can include a reference shuffler and a loop filter. An ADC can achieve better performance with incremental adjustment of a pointer of the reference shuffler, changing coefficients of the loop filter, and storing calibration codes of the ADC in a non-volatile memory. By incrementally adjusting a pointer of the reference shuffler, a calibration can be performed more efficiently than with a random adjustment of the pointer. By temporarily changing the loop filter coefficients, a greater amount of activity can be introduced into the loop filter. This activity can allow the calibration to proceed more efficiently. By storing the calibration codes in a non-volatile memory, a search space for calibration codes can be reduced. Thus, a calibration can occur more quickly, and the calibration itself can be improved.

Abstract: Disclosed herein are systems and techniques for remote bus enable. In some embodiments, a communication system with remote enable functionality may include: a master transceiver coupled to a downstream link of a bus; a voltage regulator, wherein the voltage regulator has a voltage output and an enable input, and the voltage output is coupled to the master transceiver; and a switch coupled to the enable input of the voltage regulator.

Abstract: The disclosure relates to the manufacture of inductive components, in particular transformers, using a combination of microfabrication techniques and discrete component placement. By using a prefabricated core, the core may be made much thicker than one that is deposited using microfabrication techniques. As such, saturation occurs later and the efficiency of the transformer is improved. This is done at a much lower cost than the cost of producing a thicker core by depositing multiple layers using microfabrication techniques.

Abstract: A two-axis microelectromechanical systems (MEMS) gyroscope having four proof masses disposed in respective quadrants of a plane is described. The quad proof mass gyroscope may comprise an inner coupler passing between a first and a third proof mass and between a second and a fourth proof mass, and coupling the four proof masses with one another. The quad proof mass gyroscope may further comprising a first outer coupler coupling the first and the second proof masses and a second outer coupler coupling the third and the fourth proof masses. The outer couplers may have masses configured to balance the center of masses of the four proof masses, and may have elastic constants matching the elastic constant of the inner coupler. The quad gyroscope may further comprise a plurality of sense capacitors configured to sense angular rates.

Abstract: A circuit for compensation of baseline voltage wander operating at an input of an isolator is disclosed. The circuit can compensate electronically the frequency response of an isolation circuit (e.g., a transformer) by increasing the pass band in the low frequency region in order to minimize the baseline wander caused by low inductance windings. The compensation circuit can be used to inject a current ramp proportional to the amplitude and the duration of the pulse and inversely proportional to the open circuit inductance of the isolation circuit.

Abstract: Heart rate monitors are plagued by noisy photoplethysmography (PPG) data, which makes it difficult for the monitors to output a consistently accurate heart rate reading. Noise is often caused by motion. Using known methods for processing accelerometer readings that measure movement to filter out some of this noise may help, but not always. The present disclosure describes an improved front-end technique (time-domain interference removal) based on using adaptive linear prediction on accelerometer data to generate filters for filtering the PPG signal prior to tracking the frequency of the heartbeat (heart rate). The present disclosure also describes an improved back-end technique based on steering the frequency of a resonant filter in order to track the heartbeat. Implementing one or both of these techniques leads to more accurate heart rate measurements.

Abstract: Embodiments of the present disclosure provide code readers for reading codes provided as patterns imprinted on objects. Light interacts with a pattern by e.g. being reflected from or transmitted through the pattern, and at least some of the light that has interacted with the pattern is incident on photosensitive element(s) of one or more photodetectors of a code reader. The code reader employs centroid-measuring photodetector(s), i.e. photodetectors that detect light in such a manner that centroid of a pattern can be obtained directly from the photocurrents generated as a result of the photosensitive elements detecting light incident thereon. The code reader is then configured to process the detected light to determine a centroid of the pattern from the detected light and to decode data encoded in the pattern based on a position of the centroid. Such code readers are substantially less complex than camera-based devices and avoid mechanical scanning.

Abstract: Disclosed herein are differential amplifiers for improved slew performance. In some embodiments, a differential amplifier may receive positive and negative input signals at first and second transistor branches, respectively; provide a dynamic bias current to the first and second transistor branches, responsive to the positive and negative input signals; and provide positive and negative output signals at the second and first transistor branches, respectively.

Abstract: Techniques for synchronization between multiple sampling circuits using a single pin interface to control an output data rate are described. The frequency or rate of a signal on this pin can be automatically determined and used to accomplish the required output data rate. Also described are techniques for using a single pin interface that can allow a sampling device to operate either in a master mode that can generate data strobes, or in a slave mode that can receive a convert start signal. Also described are techniques for controlling bandwidth and throughput for individual channels in a multi-channel device using a single pin interface. For example, using various techniques of this disclosure, integer multiple rate control for other channels can be provided thereby providing varying ODR for different channels, which can also control the bandwidth of interest.

Abstract: A “windowless” H-bridge buck-boost switching converter includes a regulation circuit with an error amplifier which produces a ‘comp’ signal, a comparison circuit which compares ‘comp’ with a ‘ramp’ signal, and logic circuitry which receives the comparison circuit output and a mode control signal indicating whether the converter is to operate in buck mode or boost mode and operates the primary or secondary switching elements to produce the desired output voltage in buck or boost mode, respectively. A ‘ramp’ signal generation circuit operates to shift the ‘ramp’ signal up by a voltage Vslp(p?p)+Vhys when transitioning from buck to boost mode, and to shift ‘ramp’ back down by Vslp(p?p)+Vhys when transitioning from boost to buck mode, thereby enabling the converter to operate in buck mode or boost mode only, with no need for an intermediate buck-boost region.