Abstract: A differential current signal circuit is described which includes a voltage to differential current converter circuit that generates a differential pair of current output signals in response to receiving a voltage input signal, where the differential pair of current output signals are linearly proportional to the voltage input signal within a voltage operating range from a minimum operating voltage to a maximum operating voltage. The differential pair of current output signals are linear over a wide range of voltage input signals. A correction circuit is included which eliminates voltage offsets in the voltage operating range due to process and temperature variations. The correction circuit also provides the capability to adjust the minimum operating voltage, and eliminates variations in the minimum operating voltage due to process and temperature variations.

Abstract: The disclosed power-on reset circuit provides an indication of when and whether a supply voltage Vdd has reached a trigger voltage level Vtrig. The disclosed circuit includes a flip-flop circuit and a first comparator circuit. The circuit according to the invention has a D input node of the flip-flop circuit coupled to the supply voltage. The first comparator circuit outputs a clock signal, where the flip-flop circuit is clocked by the clock signal. A Q output node of the flip-flop circuit provides the power-on reset signal, where the power-on reset signal is in a LO state when the supply voltage is at a voltage level that is less than the trigger voltage level Vtrig. The power-on reset signal is in a HI state when the supply voltage is at a voltage level that is greater than the trigger voltage level Vtrig.

Abstract: A variable phase amplifier circuit is disclosed and its method of use in tuning devices having resonators. The variable phase amplifier receives an input differential signal pair. The input differential signal pair can be generated by a resonator device. The variable phase amplifier generates a modified differential signal pair in response to receiving the input differential signal pair. The variable phase amplifier provides a means to vary the phase of the modified differential signal pair with respect to the input differential signal pair, in an accurate and stable manner. If the modified differential signal pair with a phase shift introduced in it is fed back to the resonator device, the resonator will change its frequency of oscillation, where the new frequency of oscillation is a function of the phase of the modified differential signal pair.

Abstract: Micromechanical membranes suitable for formation of mechanical resonating structures are described, as well as methods for making such membranes. The membranes may be formed by forming cavities in a substrate, and in some instances may be oxidized to provide desired mechanical properties. Mechanical resonating structures may be formed from the membrane and oxide structures.

Abstract: A system that incorporates the subject disclosure may include, for example, a method for producing an electrical signal from an apparatus comprising an induction coil coupled to a mechanical resonator, wherein the electrical signal has an operating frequency proportional to a mechanical resonating frequency of the mechanical resonator and proportional to a change in a magnetic flux resulting from a change in orientation in the apparatus, detecting with a detection circuit a change in the electrical signal resulting from a change in the magnetic flux caused by the change in orientation in the apparatus, and determining a direction of the apparatus according to the change in the electrical signal. Other embodiments are disclosed.