A receiver front end (300) having low noise amplifiers (LNAs) is disclosed herein. A cascode having a “common source” configured input FET and a “common gate” configured output FET can be turned on or off using the gate of the output FET. A first switch (235) is provided that allows a connection to be either established or broken between the source terminal of the input FET of each LNA. A drain switch (260) is provided between the drain terminals of input FETs to place the input FETs in parallel. This increases the g.sub.m of the input stage of the amplifier, thus improving the noise figure of the amplifier.

Aspects of this disclosure relate to a band pass filter that includes LC resonant circuits coupled to each other by a capacitor. A bridge capacitor can be in parallel with series capacitors, in which the series capacitors include the capacitor coupled between the LC resonant circuits. The bridge capacitor can create a transmission zero at a frequency below the passband of the band pass filter. The LC resonant circuits can each include a surface mount capacitor and a conductive trace of the substrate, and an integrated passive device die can include the capacitor. Band pass filters disclosed herein can be relatively compact, provide relatively good out-of-band rejection, and relatively low loss.

Methods, systems, and devices for differential amplifier schemes for sensing memory cells are described. In one example, a memory apparatus may include a differential amplifier having a first input node configured to be coupled with a memory cell and having an output node configured to be coupled with a sense component. In some examples, the memory apparatus may also include a capacitor having a first node coupled with the first input node, and a first switching component configured to selectively couple a second node of the capacitor with the output node. The differential amplifier may configured such that a current at the output node is proportional to a difference between a voltage at the first input node of the differential amplifier and a voltage at the second input node of the differential amplifier.

A provided impedance measuring semiconductor circuit can suppress the influence of sensors on the measurements of other sensors in the measurements of the sensors. According to an embodiment, an impedance measuring semiconductor circuit includes a first resistance element, an operational amplifier having a positive input terminal and an output terminal, the positive input terminal receiving a predetermined set voltage, the output terminal being coupled to one end of the first resistance element, a first output-side switch that electrically couples or decouples a first sensor and the other end of the first resistance element, a second output-side switch that electrically couples or decouples a second sensor and the other end of the first resistance element, a first input-side switch that electrically couples or decouples the first sensor and a negative input terminal, and a second input-side switch that electrically couples or decouples the second sensor and the negative input terminal.

A variable level power clamping circuit that may be used for the bypass path of an RF receiver having a low-noise amplifier (LNA). Impedance transform circuitry is used to transform the impedance of a signal path to a higher or lower impedance at a clamping circuit, causing the voltage at the clamping circuit to be, respectively, higher (thus clamping at a lower power level) or lower (thus clamping at a higher power level), and then transform the impedance after the clamping circuit to another value, such as to the impedance of the signal path. In a variant embodiment, the clamping circuit and an impedance matching element coupled to an LNA amplification path are re-purposed by selectively connecting those circuit elements to the LNA bypass path through a suitable impedance transform element when in a bypass mode.

An audio processing circuit includes a cascade operational amplifier circuit, an output node, and a pull-down circuit. The cascade operational amplifier circuit includes a first operational amplifier circuit and a second operational amplifier circuit. The first operational amplifier circuit includes a main operational amplifier and a secondary operational amplifier that are connected in parallel. The pull-down circuit is configured to pull down a voltage at the output node after the first operational amplifier circuit is turned on. The second operational amplifier circuit is configured to, after the secondary operational amplifier is turned on, control a voltage gain of the secondary operational amplifier to change gradually from low to high.

RF signal amplifiers are provided that include an RF input port, one or more active RF output ports, one or more passive RF output ports, an active communication path, and a passive communication path. Various embodiments include one or more switching devices, one or more directional couplers, one or more diplexers, a power divider network, and/or an attenuator.

Describe is a buffer which comprises: a differential source follower coupled to a first input and a second input; first and second current steering devices coupled to the differential source follower; and a current source coupled to the first and second current steering devices. The buffer provides high supply noise rejection ratio (PSRR) together with high bandwidth.

A receiver includes a first T-coil circuit at an input of the receiver and configured to receive an input signal, a termination impedance coupled to the first T-coil circuit and configured to match an impedance of a transmission line coupled to the first T-coil circuit, and an amplifier including a first input and a second input and configured to amplify a differential signal at the first and second inputs, a calibration switch coupled to the amplifier and configured to selectively electrically connect or disconnect the first and second inputs of the amplifier, and a first receive switch configured to selectively electrically connect or disconnect a center node of the first T-coil circuit and the amplifier.

A multi-mode envelope tracking (ET) amplifier circuit is provided. The multi-mode ET amplifier circuit can operate in a low-resource block (RB) mode, a mid-RB mode, and a high-RB mode. The multi-mode ET amplifier circuit includes fast switcher circuitry having a first switcher path and a second switcher path and configured to generate an alternating current (AC) current. A control circuit activates the fast switcher circuitry in the mid-RB mode and the high-RB mode, while deactivating the fast switcher circuitry in the low-RB mode. More specifically, the control circuit selectively activates one of the first switcher path and the second switcher path in the mid-RB mode and activates both the first switcher path and the second switcher path in the high-RB mode. As a result, it is possible to improve efficiency of ET tracker circuitry and the multi-mode ET amplifier circuit in all operation modes.