A Highly Linear SAW-Less CMOS Receiver Using a Mixer With Embedded Tx Filtering for CDMA

An embedded filtering passive (EFP) mixer is used to overcome transmitter power leakage in a receiver without the use of a SAW filter. The receiver IC exhibits more than + 60 dBm of Rx IIP₂ , 2.4 dB Rx noise figure, and +77 dB of Triple Beat (TB) with 45 MHz offset transmit leakage at 900 MHz Rx frequency while consuming only 18 mA from a 2.1 V supply. Thanks to the embedded filtering passive mixer, the proposed receiver IC shows an additional 15 dB Tx rejection compared to a conventional receiver. The additional Tx rejection improved the IIP ₂ by 10 dB and TB by 30 dB. The complete receiver consists of a differential LNA employing an active post-distortion (APD), I/Q embedded filtering passive mixer, two TIAs for I/Q outputs. The fabricated receiver IC occupies 2.25 mm² including bonding pads, ESD devices, local oscillator (LO) input buffer, frequency divider, and mixer drivers. The receiver is fabricated using a 0.18 mum CMOS process with 5 metal and 1 poly (5M1P) layer.