A digital buffer device with self-calibration includes a first buffer circuit, detection circuit, and calibration circuit. The first buffer circuit has a buffer input terminal for receiving an input signal and a buffer output terminal as output of the digital buffer device. The detection circuit includes at least one second buffer circuit for receiving at least one reference signal and generating at least one detection signal to indicate circuit characteristic variations of the at least one second buffer circuit. The at least one second buffer circuit is of a same type of buffer as the first buffer circuit. The calibration circuit has a calibration input terminal for receiving the input signal, and a calibration output terminal coupled to the buffer output terminal. The calibration circuit is for calibrating the first buffer circuit to generate an output signal according to the input signal and the at least one detection signal.

In a transistor turnoff system, a transistor control circuit is configured to adjust a control voltage at a transistor control output responsive to a comparison signal at a control input. The control voltage has a slew rate. A comparator has a comparator output and first and second comparator inputs. The first comparator input is coupled to the transistor control output. The comparator is configured to: provide the comparison signal at the comparator output based on a reference voltage at the second comparator input; and deactivate the transistor control circuit by changing a state of the comparison signal responsive to the control voltage falling below the reference voltage. A slew-rate compensator is configured to increase the reference voltage by a compensation voltage that compensates for a time delay of the comparator or the transistor control circuit. The compensation voltage is proportional to the slew rate.

A method for controlling access to a chip includes obtaining first values of a first physically unclonable function of the chip, obtaining second values that correspond to at least one challenge word, performing a simulation based on the first values and the second values, and generating an authentication result for the chip based on results of the simulation. The simulation may generate responses to logical operations corresponding to combinatorial logic in the chip, and the logical operations may be performed based on a predetermined sequence of the first values and the second values. The chip may be authenticated based on a match between the responses generated by the simulation and a second physically unclonable function of the chip.

An apparatus includes a differential input pair, a first resistor, a second resistor, and a comparator. The differential input pair having first and second differential inputs. The first differential input is adapted to be coupled to an output of a controller and the second differential input is adapted to be coupled to a signal ground of the controller. The first resistor is adapted to be coupled to a third resistor via the first differential input to form a first voltage divider. The second resistor is adapted to be coupled to a fourth resistor via the second differential input to form a second voltage divider. The comparator having first and second comparator inputs. The first comparator input is coupled between the first resistor and the first differential input. The second comparator input is coupled between the second resistor and the second differential input.

An electronic device may include one or more output buffers each including a pair of final p-channel metal oxide semiconductor (PMOS) and n-channel metal oxide semiconductor (NMOS) transistors, a first pre-buffer to drive the PMOS transistor, and a second pre-buffer to drive the NMOS transistor. Each output buffer receives power from a pre-buffer supply filtering circuit, which may include a supply capacitor for stabilizing supply voltage, a low-pass first pre-buffer supply filter to filter the voltage supplied to the first pre-buffer, and a low-pass second pre-buffer supply filter the voltage supplied to the second pre-buffer.

A voltage fluctuation detection circuit includes: a source voltage decrease detection circuit configured to detect a decrease in voltage of a first power supply which outputs a first voltage and to output the result of detection as a voltage decrease detection signal using a second voltage which is lower than the voltage of the first power supply; an erroneous detection prevention circuit configured to detect an increase in voltage of the first power supply and to output the result of detection as a voltage increase detection signal using the second voltage; and a transistor configured to mask outputting of the voltage decrease detection signal in a period in which the increase in voltage of the first power supply is being detected based on the voltage increase detection signal.

A circuit includes: a first swing reduction circuit coupled between an input/output pad and a buffer circuit, and a second swing reduction circuit coupled between the input/output pad and the buffer circuit. The first swing reduction circuit comprises a first transistor gated by a first bias voltage and comprises a second transistor drained by the first bias voltage. The first swing reduction circuit is configured to increase a voltage at a first node in the buffer circuit when a voltage applied on the input/output pad is equal to a first supply voltage. The second swing reduction circuit is configured to reduce a voltage at a second node in the buffer circuit when the voltage applied on the input/output pad is equal to a second supply voltage.

A skew compensation circuit includes a skew detection circuit configured to generate skew detection signals by detecting a skew characteristic of a basic logic element constituting a semiconductor apparatus, a skew compensation signal generation circuit configured to generate a skew compensation signal by comparing the skew detection signals and a plurality of reference voltages, a variable delay circuit configured to generate a compensation signal by delaying an input signal by a delay time varied according to the skew compensation signal, and a reference voltage generation circuit configured to generate the plurality of reference voltages of which offset components are compensated for according to variations of a temperature and an external voltage.

An electronic system includes a reception device and a transmission device. The reception device generates reception data from transmission data input to a reception node and includes a termination circuit which is coupled to the reception node to perform an impedance matching operation. The transmission device generates a drive control signal from internal data based on a mode signal and drives the transmission data based on the drive control signal.

An electronic system includes a reception device and a transmission device. The reception device generates reception data from transmission data input to a reception node and includes a termination circuit which is coupled to the reception node to perform an impedance matching operation. The transmission device generates a drive control signal from internal data based on a mode signal and drives the transmission data based on the drive control signal.