Differential amplifier in low voltage and low power consumption and high isolation

Abstract

Two MOSFETs connected in common source mode are as input ends of the differential signal of amplifier. Resistance, inductance or other active device is adopted as load as well as feedback element at source end of amplifier or trail current source. Two MOSFETs identical to two input MOSFETs in common source mode are added. Gate end of one MOSFET is connected to gate end of input MOSFET for inputting positive signal; and drain end is connected to drain end of input MOSFET for inputting negative signal (negative output end). Gate end of the other MOSFET is connected to gate end of input MOSFET for inputting negative signal; and drain end is connected to drain end of input MOSFET for inputting positive signal (positive output end). The invention takes full advantage of identical gate-drain capacitances of MOSFET parts operated at saturation region and cutoff region. Features are: low voltage, low power consumption and high degree of reverse isolation.

Description

technical field [0001] The invention belongs to the application technical field of low-voltage and low-power CMOS RFIC in the deep submicron era, and is especially suitable for a low-noise amplifier (LNA) in a radio frequency CMOS integrated circuit (RFIC). Background technique [0002] As CMOS VLSI technology enters the era of 65nm technology, the field effect transistor in the circuit has a serious short channel effect, which is manifested by the decrease of the threshold voltage (threshold voltage) as the channel length decreases. The threshold voltage decreases with the increase of the drain terminal voltage, and the intrinsic output resistance of the device is reduced due to the direct source-drain punch-through (punch-through) channel length modulation effect. The second-order effect of the device caused by the short channel effect is easy to cause circuit failure. Therefore, the suppression of short-channel effects is an urgent problem to be solved to improve the per...

AI Technical Summary

Problems solved by technology

However, because only a single tube is used, the isolation effect between the input and output terminals will become very poor due to the Miller effect, so the application range of this structure is limited in the actual application process.

Especially the application at high frequency is more difficult, because it will make the stability of the circuit a big problem

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