Single-pole double-throw radio frequency switch circuit

Abstract

The invention relates to a single-pole double-throw radio frequency switch circuit which comprises a receiving branch circuit and a transmitting branch circuit. A source electrode of a second NMOS tube MN2 in the receiving branch circuit is connected with an antenna end ANT of the transmitting branch circuit through a second capacitor C2; a source electrode of a fifth NMOS tube MN5 in the transmitting branch circuit is connected with an antenna end ANT of the transmitting branch circuit through a sixth capacitor C6; when the transmitting mode enabling end TXEN is at a high level and the receiving mode enabling end RXEN is at a low level, the transmitting branch circuit is switched on, and the receiving branch circuit is switched off; and when the transmitting mode enabling end TXEN is at a low level and the receiving mode enabling end RXEN is at a high level, the receiving branch circuit is switched on, and the transmitting branch circuit is switched off, so that time division multiplexing of a common antenna end ANT of the transmitting branch circuit and the receiving branch circuit is realized. According to the invention, the problem of poor isolation and linearity of the radio frequency switch under a high-power signal working condition can be avoided.

Description

technical field [0001] The invention relates to a radio frequency switch circuit, in particular to a single pole double throw radio frequency switch circuit, which belongs to the technical field of integrated circuit design. Background technique [0002] In recent years, with the rapid development of information technology, the wireless communication industry has also ushered in rapid growth. The radio frequency switch is a key module in the radio frequency wireless transceiver system, which can realize the function of controlling the signal flow of radio frequency signals, whether it is Bluetooth, WIFI equipment, or mobile communication equipment, almost every product related to wireless applications requires the use of radio frequency switches. Similarly, the requirements for higher linearity, lower insertion loss, and higher isolation are put forward for radio frequency switches. [0003] Conventional SPDT RF switches such as figure 1 As shown, when the transmitting mode...

AI Technical Summary

Problems solved by technology

[0004] The invention aims at the problem that the isolation and linearity of the traditional single-pole double-throw radio frequency switch will deteriorate under the working condition of high-power signals, thereby providing a single-pole double-throw radio frequency switch circuit. The source and drain terminals of the series-parallel NMOS transistors in the road are incorporated into a resistor, and the level of the source and drain terminals is pulled down and pulled up when the NMOS tube is turned on and off, which can block the radio frequency signal and improve Linearity and isolation of RF switches in transmit and receive modes

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