A combined resistance circuit 2A includes a first circuitry 20A provided between a first end 2a and a second end 2b. This first circuitry 20A includes a resistor R1 provided between a node N11 and a node N12, a resistor R2 provided between the node N12 and a node N13, a resistor R3 provided between the node N13 and a node N14, a resistor R4 provided between the node N14 and the node N11, a resistor R5 provided between the node N11 and the node N13, a switch SW0 provided in series to the resistor R4 between the node N14 and the node N11, and a switch SW1 provided in series to the resistor R2 between the node N12 and the node N13. The node N12 is connected to the first end and the node N14 is connected to the second end.

Hybrid-coding, multi-cell architecture and operating techniques for step devices provide advantages over binary-coded and thermometer-coded step devices by minimizing or avoiding glitches common in the transient response of binary-coded step devices and by minimizing or avoiding significant increases or degradation in one or more of area, package dimensions, pin counts, power consumption, insertion loss and parasitic capacitance common to thermometer-coded step devices having equivalent range and resolution.

A circuit comprises a Sallen-Key filter, which includes a source follower that implements a unity-gain amplifier; and a programmable-gain amplifier coupled to the Sallen-Key filter. The circuit enables programmable gain via adjustment to a current mirror copying ratio in the programmable-gain amplifier, which decouples the bandwidth of the circuit from its gain settings. The programmable-gain amplifier can comprise a differential voltage-to-current converter, a current mirror pair, and programmable output gain stages. The Sallen-Key filter and at least one branch in the programmable-gain amplifier can comprise transistors arranged in identical circuit configurations.

A circuit having a DC-to-DC converter and an input circuit connected on the line side of the DC-to-DC converter, having a first terminal and a second terminal for connection to a power supply and a third terminal and a fourth terminal for connection to the DC-to-DC converter. Between the first and third terminals, the input circle has a semiconductor element, wherein a first component terminal of the semiconductor element is connected via at least a first capacitor and a second capacitor to a second component terminal of the semiconductor element, wherein a resistance of the semiconductor element is controllable by a voltage between the first component terminal and the second component terminal.

A wideband variable gain amplifier (VGA) having a low phase change is disclosed. The first VGA amplifies an input signal by a current steering manner so that an amplification gain is variable. The larger a variable gain amount of the first output signal amplified by the first VGA is, the more a relative phase change amount gradually increases in either positive direction or negative direction. The second VGA further amplifies the first amplified output signal in the current steering manner so as to vary the amplification gain. As a variable gain amount of a second output signal amplified by the second VGA becomes larger, a relative phase change amount gradually increases in a direction opposite to the phase change direction of the first VGA. This opposing phase changes of the first and second VGAs are canceled against each other to provide a variable amplification gain over the wideband frequency range with a low phase change.

A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

A radio frequency switch is disclosed. The RF switch uses a combination of transistor technology and a topology to create an RF switch that has a high isolation and a high voltage breakdown at frequencies including those above a gigahertz.

A number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

A wideband variable gain amplifier (VGA) having a low phase change is disclosed. The first VGA amplifies an input signal by a current steering manner so that an amplification gain is variable. The larger a variable gain amount of the first output signal amplified by the first VGA is, the more a relative phase change amount gradually increases in either positive direction or negative direction. The second VGA further amplifies the first amplified output signal in the current steering manner so as to vary the amplification gain. As a variable gain amount of a second output signal amplified by the second VGA becomes larger, a relative phase change amount gradually increases in a direction opposite to the phase change direction of the first VGA. This opposing phase changes of the first and second VGAs are canceled against each other to provide a variable amplification gain over the wideband frequency range with a low phase change.

An apparatus includes a bypass circuit a resistor circuit and multiple staggered circuits. The bypass circuit may have a predetermined number of a plurality of transistors connected in series between an input node and an output node. The resistor circuit may have a given number of resistors connected in series between the input node and the output node. Adjoining pairs of the resistors may be connected at given nodes. The staggered circuits may be connected between the given nodes and either the input node or the output node. Each staggered circuit may have a respective number of the transistors connected in series. The bypass circuit, the resistor circuit and the staggered circuits may form part of a bridge attenuator.