An example apparatus includes a polyphase transconductance-capacitor filter. The polyphase filter includes a DC bias voltage node, a plus in-phase filter unit, a minus in-phase filter unit, a plus quadrature-phase filter unit, and a minus quadrature-phase filter unit. Each filter unit respectively includes an input node, an output node, and a control node. The polyphase filter also includes a plus in-phase switch and a minus in-phase switch. The plus in-phase switch is coupled to the control node of the plus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit. The minus in-phase switch is coupled to the control node of the minus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit.

A thin film transistor includes a gate electrode, a gate insulating layer, a carbon nanotube structure, a source electrode and a drain electrode. The gate insulating layer is located on the gate electrode. The carbon nanotube structure is located on the gate insulating layer. The source electrode and the drain electrode are arranged at intervals and electrically connected to the carbon nanotube structure respectively. The thin film transistor further includes an interface charge layer, and the interface charge layer is located between the carbon nanotube structure and the gate insulating layer.

A thin film transistor includes a gate electrode, a gate insulating layer, a carbon nanotube structure, a source electrode and a drain electrode. The gate insulating layer is located on the gate electrode. The carbon nanotube structure is located on the gate insulating layer. The source electrode and the drain electrode are arranged at intervals and electrically connected to the carbon nanotube structure respectively. The thin film transistor further includes an interface charge layer, and the interface charge layer is located between the carbon nanotube structure and the gate insulating layer.

A protection device includes a first inductive element connecting first and second terminals and a second inductive element connecting third and fourth terminals. A first component includes a first avalanche diode connected in parallel with a first diode string, anodes of the first avalanche diode and a last diode in the string being connected to ground, cathodes of the first avalanche diode and a first diode in the string being connected, and a tap of the first diode string being connected to the first terminal. A second protection component includes a second avalanche diode connected in parallel with a second diode string, anodes of the second avalanche diode and a last diode in the string being connected to ground, cathodes of the second avalanche diode and a first diode in the string being connected, and a tap of the second diode string being connected to the third terminal.

A protection device includes a first inductive element connecting first and second terminals and a second inductive element connecting third and fourth terminals. A first component includes a first avalanche diode connected in parallel with a first diode string, anodes of the first avalanche diode and a last diode in the string being connected to ground, cathodes of the first avalanche diode and a first diode in the string being connected, and a tap of the first diode string being connected to the first terminal. A second protection component includes a second avalanche diode connected in parallel with a second diode string, anodes of the second avalanche diode and a last diode in the string being connected to ground, cathodes of the second avalanche diode and a first diode in the string being connected, and a tap of the second diode string being connected to the third terminal.

A high-frequency amplifier for an active EMI filter with a symmetric class B emitter-follower output stage driven by a driver stage, with a sense output resistor. Both terminals of the sense resistor are brought to the noninverting, respecting inverting input of the driver stage through two dividers of the same ratio, in a global voltage feedback loop. The amplifier is configured to provide a high output impedance at 10 kHz and up to 100 MHz, a peak-to-peak output current of 2-10 ampere and a low quiescent current of less than 400 mA. The invention includes EMI filters with such a high-frequency current source, for example in the current-sense current-inject feedback configuration.

A high-frequency amplifier for an active EMI filter with a symmetric class B emitter-follower output stage driven by a driver stage, with a sense output resistor. Both terminals of the sense resistor are brought to the noninverting, respecting inverting input of the driver stage through two dividers of the same ratio, in a global voltage feedback loop. The amplifier is configured to provide a high output impedance at 10 kHz and up to 100 MHz, a peak-to-peak output current of 2-10 ampere and a low quiescent current of less than 400 mA. The invention includes EMI filters with such a high-frequency current source, for example in the current-sense current-inject feedback configuration.

Techniques and apparatus for reducing low frequency power supply spurs in clock signals. One example circuit generally includes a first power supply circuit configured to generate a first power supply voltage on a first power supply rail, a second power supply circuit configured to generate a second power supply voltage on a second power supply rail, a clock distribution network, and a feedback circuit coupled between the second power supply rail and at least one input of the first power supply circuit. The feedback circuit may be configured to sense the second power supply voltage, to process the sensed second power supply voltage, and to output at least one feedback signal to control the first power supply circuit based on the processed second power supply voltage. The clock distribution network may include first and second sets of clock drivers powered by the first and second power supply voltages, respectively.

Techniques and apparatus for reducing low frequency power supply spurs in clock signals. One example circuit generally includes a first power supply circuit configured to generate a first power supply voltage on a first power supply rail, a second power supply circuit configured to generate a second power supply voltage on a second power supply rail, a clock distribution network, and a feedback circuit coupled between the second power supply rail and at least one input of the first power supply circuit. The feedback circuit may be configured to sense the second power supply voltage, to process the sensed second power supply voltage, and to output at least one feedback signal to control the first power supply circuit based on the processed second power supply voltage. The clock distribution network may include first and second sets of clock drivers powered by the first and second power supply voltages, respectively.

A low noise amplifier for an RF sampling analog front end. The amplifier includes digital step attenuation for applying a selected attenuation to signals received at an input node, and a gain stage coupled to amplify the attenuated signal from the digital step attenuation circuit. In a differential amplifier implementation, a first input capacitor is coupled between a positive side input node and an output of the negative side digital attenuation circuit, and a second input capacitor is coupled between a negative side input node and an output of the positive side digital step attenuation circuit. In some embodiments, variable feedback circuits are coupled between each input node and an output of the corresponding gain stage, to selectively apply active termination at the input at high gain settings of the amplifier. Variable input and output resistors, and programmable noise filtering at the output, are provided in some embodiments.