A 5 mm $^{2}$ 40 nm LP CMOS Transceiver for a Software-Defined Radio Platform

A 5 mm² transceiver front-end suitable for a software-defined radio (SDR) platform is implemented in a 40-nm LP digital CMOS technology. Tailored for all modern communication standards relevant for a modern handheld mobile device (2G/3G/4G cellular, WLAN, Bluetooth, GPS, broadcasting, etc.), it uses radio architectures and circuits that ensure flexible performance at a minimal cost in area and power consumption. The receive section features four parallel LNAs to cover the frequency range from 100 MHz up to 6 GHz, a 25 % duty cycle passive mixer with IIP2 calibration, fifth-order baseband filtering up to 20 MHz, variable-gain amplification, and a 10-b 65 MS/s 34 fj/conv-step SAR ADC. It achieves NF down to 2.4 dB, more than 30-dB EVM and 50-dBm IIP2. In the transmit section, main emphasis is given to the out-of-band noise requirement that enables SAW-less operation in FDD systems: a flexible reconstruction filter is followed by a voltage-sampling mixer and a variable gain PPA. The TX chain achieves 3.2% EVM at 0-dBm output power, with CNR down to-156 dBc/Hz. For frequency synthesis, two dual-VCO 5.9-12.8 GHz fractional-N PLLs are implemented together with a chain of divide-by-2 circuits for quadrature generation.