Abstract: An amplifier with integrated filter (e.g., an LNA) is described. In one design, the amplifier may include a gain stage, a filter stage, and a buffer stage. The gain stage may provide signal amplification for an input signal. The filter stage may provide filtering for the input signal. The buffer stage may buffer a filtered signal from the filter stage. The amplifier may further include a second filter stage and a second buffer stage. The second filter stage may provide additional filtering for the input signal. The second buffer stage may buffer a second filtered signal from the second filter stage. All of the stages may be stacked and coupled between a supply voltage and circuit ground. The filter stage(s) may implement an elliptical lowpass filter. Each filter stage may include an inductor and a capacitor coupled in parallel and forming a resonator tank to attenuate interfering signals.

Abstract: A method and apparatus for detecting a jammer comprising sampling an input signal; downconverting and sampling the input signal to generate a sampled downconverted (SD) input signal; comparing the sampled input signal to a wideband threshold THWB, and comparing the SD input signal to a narrowband threshold THNB; generating a wideband (WB) interrupt signal based on the comparison to the THWB, and generating a narrowband (NB) interrupt signal based on the comparison to the THNB; and generating a composite interrupt signal based on at least one of WB interrupt signal and NB interrupt signal. In one aspect, the apparatus comprises a wideband jammer detector for generating a WB interrupt signal to indicate a wideband jammer; a narrowband jammer detector for generating a NB interrupt signal to indicate a narrowband jammer; and interrupt logic for generating a composite interrupt signal based on one of WB interrupt signal and NB interrupt signal.

Abstract: Techniques for designing a highly differential single-ended-to-differential converter for use in, e.g., communications receivers. In an exemplary embodiment, an auxiliary current path including cascomp transistors is coupled to a main current path including input transistors and cascode transistors. The transistors are biased such that inter-modulation products generated by the auxiliary current path cancel out inter-modulation products generated by the main current path. In another exemplary embodiment, current source transistors for the main current path are adaptively biased depending on the level of the input signal received. In an exemplary embodiment, the techniques may be applied to designing a converter for interfacing a single-ended low-noise amplifier (LNA) output voltage with a differential mixer input in a communications receiver.

Abstract: An amplifier with integrated filter (e.g., an LNA) is described. In one design, the amplifier may include a gain stage, a filter stage, and a buffer stage. The gain stage may provide signal amplification for an input signal. The filter stage may provide filtering for the input signal. The buffer stage may buffer a filtered signal from the filter stage. The amplifier may further include a second filter stage and a second buffer stage. The second filter stage may provide additional filtering for the input signal. The second buffer stage may buffer a second filtered signal from the second filter stage. All of the stages may be stacked and coupled between a supply voltage and circuit ground. The filter stage(s) may implement an elliptical lowpass filter. Each filter stage may include an inductor and a capacitor coupled in parallel and forming a resonator tank to attenuate interfering signals.

Abstract: Techniques for designing a highly differential single-ended-to-differential converter for use in, e.g., communications receivers. In an exemplary embodiment, an auxiliary current path including cascomp transistors is coupled to a main current path including input transistors and cascode transistors. The transistors are biased such that inter-modulation products generated by the auxiliary current path cancel out inter-modulation products generated by the main current path. In another exemplary embodiment, current source transistors for the main current path are adaptively biased depending on the level of the input signal received. In an exemplary embodiment, the techniques may be applied to designing a converter for interfacing a single-ended low-noise amplifier (LNA) output voltage with a differential mixer input in a communications receiver.

Abstract: A bandgap voltage reference circuit and methods for generating a bandgap reference voltage are disclosed. An operational amplifier receives first and second input voltages from a first and second current path, respectively. A buffer stage is coupled to an output of the operational amplifier and generates third and fourth voltages on the first and second path. A temperature dependent current is generated using the third and fourth voltages in combination with a first diode, second diode and a resistor. A third current path mirrors the temperature dependent current and a temperature independent voltage is generated for the bandgap reference voltage in the third current path using the temperature dependent current in combination with a second resistor and related diode.

Abstract: According to some embodiments, an amplifier may include a transconductance stage, a tail current source stage, and an adaptive biasing stage. The transconductance stage may be configured to receive an input voltage. The tail current source stage may be configured to provide current to the transconductance stage. The adaptive biasing stage may capacitively couple the transconductance stage to the tail current source stage.

Abstract: A method and apparatus for detecting a jammer comprising sampling an input signal; downconverting and sampling the input signal to generate a sampled downconverted (SD) input signal; comparing the sampled input signal to a wideband threshold THWB, and comparing the SD input signal to a narrowband threshold THNB; generating a wideband (WB) interrupt signal based on the comparison to the THWB, and generating a narrowband (NB) interrupt signal based on the comparison to the THNB; and generating a composite interrupt signal based on at least one of WB interrupt signal and NB interrupt signal. In one aspect, the apparatus comprises a wideband jammer detector for generating a WB interrupt signal to indicate a wideband jammer; a narrowband jammer detector for generating a NB interrupt signal to indicate a narrowband jammer; and interrupt logic for generating a composite interrupt signal based on one of WB interrupt signal and NB interrupt signal.

Abstract: According to some embodiments, an amplifier may include a transconductance stage, a tail current source stage, and an adaptive biasing stage. The transconductance stage may be configured to receive an input voltage. The tail current source stage may be configured to provide current to the transconductance stage. The adaptive biasing stage may capacitively couple the transconductance stage to the tail current source stage.

Abstract: A capacitance multiplier circuit is configured to sense a current through a capacitor in an RC filter of the circuit and to multiply the current so as to achieve a capacitance multiplier effect without adding additional circuitry or requiring additional power. The circuit includes an RC filter, a first signal path connected to a filter output, and a second signal path connected to an input to the filter. A current output through the filter (iout) is split between the two paths, sensed in the first path and multiplied in the second path. The multiplied current is fed back from the second path to the filter input to raise the effective capacitance of capacitor C. The capacitance multiplier circuit, in raising the effective capacitance of the capacitor in the filter, does not affect the frequency response, linearity performance and/or stability of the overall circuit.

Abstract: A capacitance multiplier circuit is configured to sense a current through a capacitor in an RC filter of the circuit and to multiply the current so as to achieve a capacitance multiplier effect without adding additional circuitry or requiring additional power. The circuit includes an RC filter, a first signal path connected to a filter output, and a second signal path connected to an input to the filter. A current output through the filter (iout) is split between the two paths, sensed in the first path and multiplied in the second path. The multiplied current is fed back from the second path to the filter input to raise the effective capacitance of capacitor C. The capacitance multiplier circuit, in raising the effective capacitance of the capacitor in the filter, does not affect the frequency response, linearity performance and/or stability of the overall circuit.

Abstract: A bandgap voltage reference circuit and methods for generating a bandgap reference voltage are disclosed. An operational amplifier receives first and second input voltages from a first and second current path, respectively. A buffer stage is coupled to an output of the operational amplifier and generates third and fourth voltages on the first and second path. A temperature dependent current is generated using the third and fourth voltages in combination with a first diode, second diode and a resistor. A third current path mirrors the temperature dependent current and a temperature independent voltage is generated for the bandgap reference voltage in the third current path using the temperature dependent current in combination with a second resistor and related diode.