Abstract: According to one embodiment, an apparatus is for use with a remote circuit. The apparatus has a first input for receiving an input voltage, a second input for receiving a power supply voltage, and a third input for receiving an input clock having a high state corresponding to the power supply voltage and a low state corresponding to a return for the power supply voltage. The apparatus includes a first shift circuit coupled to the first input and the third input, and configured to output a first output clock, the first output clock having a low state corresponding to the input voltage. The apparatus further includes a second shift circuit coupled to the first input and the first shift circuit, and configured to output a second output clock, the second output clock having a high state corresponding to the input voltage.

Abstract: A low-dropout (LDO) regulator includes a voltage reference circuit to provide a reference voltage, a pass device including an input terminal coupled to a voltage input, an output terminal to provide an output voltage and a control terminal, and an error amplifier including a first amplifier input for receiving the reference voltage, a second amplifier input, an amplifier output coupled to the control terminal of the pass device. Additionally, the LDO regulator includes a feedback circuit including a feedback input coupled to the output terminal of the pass device and a feedback output coupled to the second amplifier input to provide a feedback signal. The LDO regulator further includes a control circuit including a non-volatile memory to store configuration data to control operation of the voltage reference circuit, the pass device, the error amplifier, and the feedback circuit to produce the output voltage.

Abstract: A circuit includes a first current path comprising a first floating-gate transistor having a programmable threshold voltage, a second current path, and a differential amplifier. The second current path includes a second floating-gate transistor having a programmable threshold voltage and a resistor. The differential amplifier includes a first input coupled to the first current path, a second input coupled to the second current path, and an output configured to control a reference current path.

Abstract: A reference circuit includes a first transistor having a first current electrode, a control electrode, and a second current electrode coupled to a power supply terminal. The reference circuit further includes a resistive element including a first terminal coupled to the control electrode of the first transistor and a second terminal coupled to the first current electrode. Additionally, the reference circuit includes a second transistor including a first current electrode coupled to the second terminal of the resistive element, a control electrode coupled to the second terminal, and a second current electrode coupled to the power supply terminal. The second transistor is configured to produce an output signal related to a voltage at the control electrode of the first transistor.

Abstract: In an embodiment, a low-dropout (LDO) regulator includes at least one of a programmable voltage reference and a programmable frequency compensation circuit and is configurable to produce an output voltage. The programmable voltage reference includes a floating-gate transistor coupled to a reference output and configurable for providing a reference voltage to an input of an error amplifier. The programmable frequency compensation circuit is responsive to a programmable current reference circuit that includes at least one floating-gate transistor that is configurable to adjust a frequency compensation parameter. A control circuit is provided to selectively program floating gates of the floating gate transistors to adjust the output voltage and/or to adjust a frequency component of the output voltage.

Abstract: A potentiometer and a method for adjusting an impedance. In accordance with an embodiment, the potentiometer may be a programmable multistage digital potentiometer that has a first stage comprising a non-shunted impedance, a second stage coupled between a reference terminal and the first stage, and a third stage coupled between the first stage and another reference terminal. In accordance with another embodiment, the potentiometer receives a wiper address and parses it into sections such that one section controls the first stage, a second portion controls portions of the second and third stages, and a third portion controls the other portions of the second and third stages to produce a desired impedance between a common wiper terminal and the reference terminals.

Abstract: In an embodiment, a circuit includes a first transistor having a first current electrode, a control electrode, and a second current electrode coupled to a power supply terminal. The circuit further includes a resistive element having a first terminal coupled to the control electrode of the first transistor and a second terminal coupled to the power supply terminal. The circuit also includes a feedback circuit for providing a first current to the first control electrode of the first transistor and for preserving substantially the first current related to a voltage at the control electrode of the first transistor, through the resistive element. The feedback circuit includes an output terminal for providing an output signal in response to a voltage at the control electrode of the first transistor. In an embodiment, the first transistor is a floating-gate device with programmable threshold voltage.

Abstract: A potentiometer and a method for adjusting an impedance. In accordance with an embodiment, the potentiometer may be a programmable multistage digital potentiometer that has a first stage comprising a non-shunted impedance, a second stage coupled between a reference terminal and the first stage, and a third stage coupled between the first stage and another reference terminal. In accordance with another embodiment, the potentiometer receives a wiper address and parses it into sections such that one section controls the first stage, a second portion controls portions of the second and third stages, and a third portion controls the other portions of the second and third stages to produce a desired impedance between a common wiper terminal and the reference terminals.

Abstract: In an embodiment, a low-dropout (LDO) regulator includes at least one of a programmable voltage reference and a programmable frequency compensation circuit and is configurable to produce an output voltage. The programmable voltage reference includes a floating-gate transistor coupled to a reference output and configurable for providing a reference voltage to an input of an error amplifier. The programmable frequency compensation circuit is responsive to a programmable current reference circuit that includes at least one floating-gate transistor that is configurable to adjust a frequency compensation parameter. A control circuit is provided to selectively program floating gates of the floating gate transistors to adjust the output voltage and/or to adjust a frequency component of the output voltage.

Abstract: A low-dropout (LDO) regulator includes a voltage reference circuit to provide a reference voltage, a pass device including an input terminal coupled to a voltage input, an output terminal to provide an output voltage and a control terminal, and an error amplifier including a first amplifier input for receiving the reference voltage, a second amplifier input, an amplifier output coupled to the control terminal of the pass device. Additionally, the LDO regulator includes a feedback circuit including a feedback input coupled to the output terminal of the pass device and a feedback output coupled to the second amplifier input to provide a feedback signal. The LDO regulator further includes a control circuit including a non-volatile memory to store configuration data to control operation of the voltage reference circuit, the pass device, the error amplifier, and the feedback circuit to produce the output voltage.

Abstract: A reference circuit includes a first transistor having a first current electrode, a control electrode, and a second current electrode coupled to a power supply terminal. The reference circuit further includes a resistive element including a first terminal coupled to the control electrode of the first transistor and a second terminal coupled to the first current electrode. Additionally, the reference circuit includes a second transistor including a first current electrode coupled to the second terminal of the resistive element, a control electrode coupled to the second terminal, and a second current electrode coupled to the power supply terminal. The second transistor is configured to produce an output signal related to a voltage at the control electrode of the first transistor.

Abstract: A circuit includes a first current path comprising a first floating-gate transistor having a programmable threshold voltage, a second current path, and a differential amplifier. The second current path includes a second floating-gate transistor having a programmable threshold voltage and a resistor. The differential amplifier includes a first input coupled to the first current path, a second input coupled to the second current path, and an output configured to control a reference current path.

Abstract: In an embodiment, a circuit includes a first transistor having a first current electrode, a control electrode, and a second current electrode coupled to a power supply terminal. The circuit further includes a resistive element having a first terminal coupled to the control electrode of the first transistor and a second terminal coupled to the power supply terminal. The circuit also includes a feedback circuit for providing a first current to the first control electrode of the first transistor and for preserving substantially the first current related to a voltage at the control electrode of the first transistor, through the resistive element. The feedback circuit includes an output terminal for providing an output signal in response to a voltage at the control electrode of the first transistor. In an embodiment, the first transistor is a floating-gate device with programmable threshold voltage.

Abstract: A crystal oscillator circuit having a parallel resonant frequency that is adjustable by switching trim capacitors in parallel with a crystal.

Abstract: Embodiments of a digital potentiometer are disclosed that require lesser numbers of components than conventional digital potentiometers. A first string of elemental impedance devices, and at least one bulk impedance device, are provided between first and second reference terminals. The first string of elemental impedance devices is tapped by wiper switches. The at least one bulk impedance device has an impedance greater than an impedance of the first string. If desired, second and third bypassable impedance device strings also may be provided between the first and second reference terminals, with the impedance of the respective second and third strings being between the impedance of the first string and the impedance of one bulk impedance device. One or more dummy structures each including an impedance device in parallel with a permanently-on switch also may be between the first and second reference terminals to improve linearity.

Abstract: Embodiments of a digital potentiometer are disclosed that require lesser numbers of components than conventional digital potentiometers. A first string of elemental impedance devices, and at least one bulk impedance device, are provided between first and second reference terminals. The first string of elemental impedance devices is tapped by wiper switches. The at least one bulk impedance device has an impedance greater than an impedance of the first string. If desired, second and third bypassable impedance device strings also may be provided between the first and second reference terminals, with the impedance of the respective second and third strings being between the impedance of the first string and the impedance of one bulk impedance device. One or more dummy structures each including an impedance device in parallel with a permanently-on switch also may be between the first and second reference terminals to improve linearity.

Abstract: A digital potentiometer includes a string of impedance units in series. The string includes identical first and second sets of impedance units whose individual impedance values increment by a power of two. One of a plurality of switches is coupled in parallel with each respective impedance unit. The switches that are coupled to the first set of impedance units receive logical control signals complementary to logical control signals received by the respective switches coupled to the second set of impedance units, so that for every impedance unit of the first set that is bypassed (not bypassed), the identical impedance unit of the second set is not bypassed (bypassed). The string may include only the first and second sets of impedance units, or may include at least one third impedance unit in series with the first and second sets in a multi-stage design.

Abstract: Embodiments of a digital potentiometer are disclosed that require lesser numbers of components than conventional digital potentiometers. A first string of elemental impedance devices, and at least one bulk impedance device, are provided between first and second reference terminals. The first string of elemental impedance devices is tapped by wiper switches. The at least one bulk impedance device has an impedance greater than an impedance of the first string. If desired, second and third bypassable impedance device strings also may be provided between the first and second reference terminals, with the impedance of the respective second and third strings being between the impedance of the first string and the impedance of one bulk impedance device. One or more dummy structures each including an impedance device in parallel with a permanently-on switch also may be between the first and second reference terminals to improve linearity.

Abstract: A digital potentiometer is disclosed that includes first, second, and third signal terminals. A chain of series-connected impedance elements with multiple tap points is connected between the first and second signal terminals. A plurality of first switching devices are each connected to a respective one of the multiple tap points and to an internal wiper node. A configurable output stage is connected between the internal wiper node and the third signal terminal. The configurable output stage includes a buffer and a second switching device. The second switching device is operable to bypass the buffer. A switching circuit controls switching of the first switching devices. The switching circuit includes a Gray-code counter, a Gray-code decoder, and a make-before-break circuit that controls the timing of the switching of the wiper switches.

Abstract: A digital potentiometer, configurable and programmable using nonvolatile memory is disclosed. A unity-gain configured, rail-to-rail operational amplifier, used as voltage follower of buffer, can be inserted, by programming, between an internal wiper terminal and an output terminal of the digital potentiometer. This way, in certain applications, it is possible to take advantage of the low output resistance given by an analog buffer. The operational amplifier can be shutdown and bypassed by a switching device to provide a circuit behavior similar to a digital potentiometer without an output buffer. Using a dual-writing circuitry, first the complemented data, then the data itself, are written in the nonvolatile memory, improving the reliability. A Gray-code counter having a single bit changed at one time and no decode glitch is present. A make-before-break circuitry gives a short overlap conduction time for any adjacent pair of switches; one being turned-off while the other is turned-on.