A low-cost SAW-less GSM/GPRS SoC with integrated connectivity and 32-kHz crystal removal in 55nm

A single-chip SoC integrates GSM/GPRS, connectivity, application processors and peripheral functions. The SoC requires no external SAW filter and TX output matching for cellular, and 32 kHz crystal is removed. Using a proposed algorithm, the Real-Time Clock (RTC) dissipates 32 µA at 1.1 V. With a 96-dB DR ADC for RX, direct frequency modulation in PLL for TX, and extensive digital assistance, the cellular transceiver size is greatly reduced to 2.2 mm
²
in 55nm digital CMOS. −111.4/−110.4 dBm RX LB/HB sensitivity was achieved and TX meets emission requirements. All radios can operate concurrently and meet their specifications.