54 results about "Cmos amplifier" patented technology

An integrated receiver with channel selection and image rejection substantially implemented on a single CMOS integrated circuit. A receiver front end provides programable attenuation and a programable gain low noise amplifier. LC filters integrated onto the substrate in conjunction with image reject mixers provide image frequency rejection. Filter tuning and inductor Q compensation over temperature are performed on chip. Active filters utilize multi track spiral inductors with shields to increase circuit Q. The filters incorporate a gain stage that provides improved dynamic range through the use of cross coupled auxiliary differential pair CMOS amplifiers to cancel distortion in a main linearized differential pair amplifier. Frequency planning provides additional image rejection. Local oscillator signal generation methods on chip reduce distortion. A PLL generates needed out of band LO signals. Direct synthesis generates in band LO signals. PLL VCOs are centered automatically. A differential crystal oscillator provides a frequency reference. Differential signal transmission throughout the receiver is used. ESD protection is provided by a pad ring and ESD clamping structure. Shunts utilize a gate boosting at each pin to discharge ESD build up. An IF VGA utilizes distortion cancellation achieved with cross coupled differential pair amplifiers having their Vds dynamically modified in conjunction with current steering of the differential pairs sources.

A class AB output stage of a CMOS amplifier has a level-shifting voltage follower constituted by a level-shifting transistor and a current source. A bias circuit replicates the level-shifting voltage follower in a feedback arrangement to produce a variable bias voltage for the current source of both the main and replica level-shifters. The arrangement serves to control the output voltage of the level-shifter such that it provides the amplifier with a relatively constant quiescent current of the output stage over variations of manufacturing process, supply voltage, and temperature. The level shifting function can be facilitated by a resistive on-state of a power-down transistor between the level-shifting and load transistors.

The present invention comprises switched capacitor amplifiers including positive feedback, semiconductor devices, wafers and systems incorporating same and methods for amplifying signals using positive feedback, while maintaining a stable gain and producing an improved signal-to-noise ratio. One embodiment includes a switched capacitor amplifier comprising a Complementary Metal Oxide Semiconductor (CMOS) amplifier, a feed-in switched capacitor, and a feedback switched capacitor. The feed-in switched capacitor operably couples an input signal to the non-inverting input of the CMOS amplifier. Similarly, the feedback switched capacitor operably couples the amplifier output to the non-inverting input to create a positive feedback loop. A capacitance of the feedback switched capacitor relative to a capacitance of the feed-in switched capacitor comprises a feedback proportion. This feedback proportion may be configured to maintain a stable gain of the switched capacitor amplifier and increase a signal-to-noise ratio of the switched capacitor amplifier, even with the switched capacitor amplifier configured in a positive feedback arrangement.

A logarithmic linear variable gain CMOS amplifier includes first and second differential pairs of transistors forming a differential input, with each differential pair of transistors including a common source node. A pair of diode-connected load transistors is connected to the first and second differential pairs of transistors, and a third differential pair of transistors is connected to the pair of diode-connected load transistors. The third differential pair of transistors include respective gates connected together and in parallel to gates of the first and second differential pairs of transistors. First and second current mirrors are respectively connected to the common source nodes of the first and second differential pairs of transistors for programmably injecting respective bias currents thereto, with a sum of the respective bias currents remaining constant.