Abstract:
Power detectors with temperature compensation and having improved accuracy over temperature are disclosed. Variations of a power detector gain over temperature is reduced by varying both the gate and drain voltages of MOS transistors within a power detector. In an exemplary design, an apparatus includes at least one MOS transistor (320), which receives an input signal (Vin), detects the power of the input signal (Vin) based on a power detection gain, and provides an output signal (lout) indicative of the power of the input signal (Vin). The at least one MOS transistor (320) is applied a variable gate bias voltage and a variable drain bias voltage in order to reduce variations of the power detection gain over temperature. At least one additional MOS transistor (322) may receive a second variable gate bias voltage and provide the variable drain bias voltage for the at least one MOS transistor.
Abstract:
Amplifiers with improved linearity and noise performance are described. In an exemplary design, an apparatus includes first through sixth transistors. The first transistor (320) receives an input signal and provides an amplified signal. The second transistor (360) receives the amplified signal and provides signal drive for an output signal. The third transistor (310) receives the input signal and provides an intermediate signal. The fourth transistor (340) provides bias for the third transistor (310) in a high linearity mode. The fifth transistor (350) receives the intermediate signal and provides signal drive for the output signal in a low linearity mode. The third (310) and fourth (340) transistors form a deboost path that is enabled in the high linearity mode to improve linearity. The third (310) and fifth (350) transistors form a cascode path that is enabled in the low linearity mode to improve gain and noise performance. The sixth transistor (330) generates distortion component used to cancel distortion component from the first transistor (320)
Abstract:
Provided is a system for implementing gain control in an amplification module comprising a first stage amplifier (308) having a number of first stage input and output ports. The first stage amplifier (308) is configured to provide first stage amplification to a received input signal (RF Input) and produce from the amplified input signal a number of output signals. Also included are a number of second stage amplifiers (310), each having second stage input and output ports, the second stage (310) input ports being respectively coupled to the first stage (308) output ports and being configured to receive the number of output signals. A gain control device (302) is also configured to control a gain of at least one of the first stage amplifier (308) and one or more of the number of second stage amplifiers (310).
Abstract:
A serial-type A/D converter that uses magnitude amplifiers ("magamps") and comparators for effecting the conversion of analog signals to Gray scale code signals that are then converted to binary digital signals by a Gray scale code-to-binary portion of the serial-type A/D converter. More specifically, a serial-type A/D converter that uses an n-bit converter that has n-1 magamps and n-comparators. The n-1 magamps are cascaded such that the VOL and VOH outputs of a stage is the inputs to the next stage. The output of the comparators are input to the Gray scale code-to-binary portion of the serial A/D converter. The latching of the comparators occurs outside of the magamps. This allows for the parallel latching of the n comparators. The speed of the serial-type A/D converter is determined by the bandwidth of the magamps. The serial-type A/D converter includes an offset method that significantly reduces the effects of early voltage, VA, on the output waveforms. Each stage of the serial-type A/D converter may have any desired gain and not limited to a particular gain.
Abstract:
An apparatus includes a plurality of amplification stages (310, 320), each stage comprising a cascode transistor (314, 324); and a bridge circuit coupled between gate terminals (316, 326) of cascode transistors (314, 324) in two adjacent stages of the plurality of amplification stages (310, 320), the bridge circuit including a plurality of diodes (330, 332).
Abstract:
An apparatus includes a differential cascode amplifier including a first transistor (304) and a second transistor (306). The apparatus further includes a transistor (320) including a source terminal coupled to a gate terminal (312) of the first transistor (304) of the differential cascode amplifier. The transistor (320) also includes a drain terminal coupled to a gate terminal (314) of the second transistor (306) of the differential amplifier.
Abstract:
Techniques for designing a low-noise amplifier (LNA) for operation over a wide range of input power levels. In an exemplary embodiment, a first gain path is provided in parallel with a second gain path. The first gain path includes a differential cascode amplifier with inductor source degeneration. The second gain path includes a differential cascode amplifier without inductor source degeneration. The cascode transistors of the gain paths may be selectively biased to enable or disable the first and/or second gain path. By selectively biasing the cascode transistors and input transistors, various combinations of the first and second gain paths may be selected to provide an optimized gain configuration for any input power level.
Abstract:
A circuit for minimizing a voltage offset between inverting and non-inverting input terminals of an operational amplifier circuit is provided. The circuit includes a chopper circuit connected to the inverting and non-inverting input terminals of the operational amplifier circuit, the chopper circuit including: an amplifier having differential outputs; and a switching circuit for periodically reversing the input terminals to the amplifier and periodically reversing the outputs of the amplifier to provide an output signal having an offset adjustment signal to the operational amplifier circuit to adjust the offset of the operational amplifier circuit.
Abstract:
The present invention provides a voltage regulator (71) especially adaptable for use with a field-programmable gate array (FPGA). The voltage regulator of the present invention rapidly generates an operating voltage for the core or nucleus logic elements upon application of external power while preventing degradation of the fuses. The core or regulated voltage of an FPGA can be set to a level that provides maximum performance with minimum power consumption or, alternatively, permits propagation delays and switching rates to be adjusted so as to compensate for die to die variation. Since it is common for electrical parameters of FPGA manufactured in different wafer fabrication facilities to vary, the voltage regulator (71) is configurable as a true voltage regulator providing its output through a switching transistor (198) or, alternatively, as a pseudo-voltage regulator providing its output through a switching transistor (188).