This document introduces a method of fast time division duplex (TDD) transmission using an upconverting mixer with a high side switch. This method achieves fast Tx switching by applying a power switch at the transmit upconverting mixer, which removes both the transmit signal and all other mixing products from the mixer RF output. This method has the advantages of low cost, good performance and power saving during the Tx off-time.
The document details a method for implementing fast on/off switching in wireless infrastructure TDD transmit applications. It proposes using supply voltage switching at the transmit upconverting mixer stage to remove the transmit signal and mixing products from the RF output, offering low cost and power savings.
A specific circuit design is provided utilizing an LT5579 high performance upconverting mixer. The high side Vcc switch circuit employs a P-channel MOSFET (IRLML6401) and an N-channel enhancement mode FET (2N7002) driven by a high speed CMOS inverter (MC74HC1G04). This configuration achieves a total turn-on time of 650ns and a total turn-off time of 500ns.
The total turn-on time is only 650ns.
The total turn-off time is 500ns.