Abstract: For sensing pH of a fluid, a heating apparatus of a semiconductor die controls a temperature of the fluid to a first temperature. A first voltage of a gate of a floating gate transistor of the semiconductor die is measured while the temperature of the fluid is at the first temperature. Also, the heating apparatus controls the temperature of the fluid to a second temperature that is different than the first temperature. A second voltage of the gate is measured while the temperature of the fluid is at the second temperature. The pH of the fluid is determined based on the first and second voltages, the first temperature and the second temperature.

Abstract: In described examples, a device includes an interconnect substrate that has an aperture through the interconnect substrate. An integrated circuit (IC) die that has an on-chip element is mounted on the interconnect substrate with the on-chip element aligned with and facing the aperture. The IC die is over-molded with mold compound only on one side of the interconnect substrate so that the aperture remains free of mold compound to allow the on-chip element to have access to the environment.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: For sensing pH of a fluid, a heating apparatus of a semiconductor die controls a temperature of the fluid to a first temperature. A first voltage of a gate of a floating gate transistor of the semiconductor die is measured while the temperature of the fluid is at the first temperature. Also, the heating apparatus controls the temperature of the fluid to a second temperature that is different than the first temperature. A second voltage of the gate is measured while the temperature of the fluid is at the second temperature. The pH of the fluid is determined based on the first and second voltages, the first temperature and the second temperature.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: Disclosed examples include multichannel RF transponder circuits with multiple transponder channel circuits individually connected to a corresponding antenna circuit, a configurable shared modulation capacitor, a channel switching circuit to selectively connect the modulation capacitor to a selected transponder channel circuit, and a modulation circuit to selectively change the capacitance value of the modulation capacitor between two or more values according to a modulation control signal to transmit uplink data using the selected transponder channel circuit.

Abstract: Described examples include an integrated circuit including a receive portion to receive an encoded transmission on a line. The receive portion has: a wake mode in which the receiver is capable of receiving the encoded transmission; and a sleep mode in which the receiver is not capable of receiving the encoded transmission. A wakeup controller monitors the line for a wakeup signal and provides a signal to the receive portion to cause the receive portion to enter the wake mode when the wakeup controller receives the wakeup signal.

Abstract: Described examples include an integrated circuit including a receive portion to receive an encoded transmission on a line. The receive portion has: a wake mode in which the receiver is capable of receiving the encoded transmission; and a sleep mode in which the receiver is not capable of receiving the encoded transmission. A wakeup controller monitors the line for a wakeup signal and provides a signal to the receive portion to cause the receive portion to enter the wake mode when the wakeup controller receives the wakeup signal.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: Disclosed examples include multichannel RF transponder circuits with multiple transponder channel circuits individually connected to a corresponding antenna circuit, a configurable shared modulation capacitor, a channel switching circuit to selectively connect the modulation capacitor to a selected transponder channel circuit, and a modulation circuit to selectively change the capacitance value of the modulation capacitor between two or more values according to a modulation control signal to transmit uplink data using the selected transponder channel circuit.

Abstract: Disclosed examples include multichannel RF transponder circuits with multiple transponder channel circuits individually connected to a corresponding antenna circuit, a configurable shared modulation capacitor, a channel switching circuit to selectively connect the modulation capacitor to a selected transponder channel circuit, and a modulation circuit to selectively change the capacitance value of the modulation capacitor between two or more values according to a modulation control signal to transmit uplink data using the selected transponder channel circuit.

Abstract: In described examples, an apparatus includes: at least one resonant circuit for receiving a radio frequency signal; a rectifier coupled to the resonant circuit to output a first rectified signal with a constant level portion and a portion matching a first portion of the radio frequency signal, and to output a second rectified signal having a constant level portion and a portion that matches a second portion of the radio frequency signal; a first limiter circuit to limit a voltage of the first rectified signal to a predetermined maximum voltage level; a second limiter circuit to limit the voltage of the second rectified signal to the predetermined maximum voltage level; a third limiter circuit to limit a voltage of the first rectified signal to a predetermined minimum voltage level; and a fourth limiter circuit to limit the voltage of the second rectified signal to the predetermined minimum voltage level.

Abstract: Disclosed examples include an RF transponder circuit with signal input nodes, a rectifier circuit with a power transistor and a current mirror circuit to generate a rectifier mirror current signal, a limiter circuit with a limiter transistor and a current mirror circuit to generate a limiter mirror current signal, and a demodulator circuit to demodulate an amplitude shift keying (ASK) RF signal received at the signal input nodes according to the rectifier and limiter mirror current signal to generate a binary demodulator data signal representing the presence or absence of a threshold amount of energy in the RF signal.

Abstract: Circuitry includes: a resonant circuit for receiving a radio frequency signal; a rectifier outputting a first rectified signal matching a portion of the radio frequency signal and a second rectified signal having portion that matches the radio frequency signal and is out of phase with the first rectified signal; a clock regenerator circuit outputting a clock waveform corresponding to the first and second rectified signals; an oscillator timing circuit forming a first sloped waveform having a linear slope and a second sloped waveform having a linear slope, and comparators to compare the first sloped waveform and the second sloped waveform. The oscillator timing circuit outputs a master clock signal having transitions when the first and the second sloped waveform have equal magnitudes. A pluck pulse generator forms a pulse of a predetermined length when the master clock signal transitions.