Broadband CMOS second-order active balun amplifier

Abstract

According to the broadband CMOS second-order active balun amplifier, a series structure of two stages of active balun is used, higher phase precision is obtained, and the requirement for high loss ofa radio frequency circuit is met. Phase shift in the transmission process from a signal source to a load is eliminated through the input pi-type matching circuit, and 50-ohm input impedance matching is achieved; the first-stage active balun circuit and the second-stage output active balun circuit are in cross coupling connection through a capacitor, and the first-stage active balun circuit uses abroadband phase correction technology to obtain Vo1 and Vo2 with small phase errors and gain errors; according to the second-stage active balun circuit, two double-end-to-single-end baluns are used asoutput ends, a traditional source follower is replaced as a buffer, the phase precision is improved through phase compensation between signals, and meanwhile output matching is achieved. The invention can be used for an active balun amplifier of 1-8GHz.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and further relates to a broadband complementary metal oxide semiconductor CMOS (Complementary Metal Oxide Semiconductor) second-order active balun amplifier for L-C bands in the technical field of radio frequency integrated circuits. The invention can be used in the wireless communication system to realize the conversion between single-end and double-end signals, and at the same time provide certain power gain and better isolation of input and output, and ensure good balance of signals. Background technique [0002] Since the beginning of the 21st century, integrated circuit design technology has developed rapidly, various new digital and radio frequency circuits have become more and more widely used, and the digital transmission frequency requirements of transmitting / receiving communication modules are also getting higher and higher. In wireless communication systems such as radio freq...

AI Technical Summary

Problems solved by technology

Under the premise of avoiding the use of signal switches to introduce additional insertion loss and additional noise, the invention makes up for the shortcomings of the passive balun's excessive volume in the intermediate frequency band, and at the same time solves the problem that the traditional active balun circuit cannot realize the signal bidirectional conversion function.

However, the shortcomings of the intermediate frequency bidirectional active balun still exist in that the single-transistor dual-circuit part of the invention adopts the single-transistor separation structure active balun structure, and realizes the differential output through simple and practical operation, which is far lower It also has a very accurate differential phase when working in the low frequency band of the millimeter wave MMW (Millimeter Waves) frequency

However, the disadvantage of this broadband active balun circuit is that the high-frequency parasitic circuit of the active balun structure of the source follower and common-gate amplifier will cause additional signal delay or cause the signal to pass through different loads, so the current signal There will be a certain phase error when passing through the common gate amplifier, and it will not be completely inverted when passing through the amplifier

Additional parasitic effect compensation technology is required to compensate for the generated errors, making the circuit have larger power consumption and lower gain

Also, in the second-order differential amplifier P 8 and P 9 Due to the size and threshold voltage mismatch between transistors, the current and transconductance flowing through the two transistors are also different. Due to the mismatch between transistors, a certain phase error and gain error will also be generated.

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