Search

A novel backgate modulation technique alleviating limitations associated with supply-regulated polar transmitters is proposed. The backgate of a partially depleted silicon-on-insulator metal–semiconductor field-effect transistor with a breakdown voltage of 15 V is used to modulate the gain and output power of an RF power amplifier (PA). The high-impedance backgate provides high-efficiency and wide-dynamic-range modulation of PA gain. Measured results at 1.8 GHz demonstrate 16% power-added efficiency improvement at 6-dB backed-off output power, compared with the same RF PA without backgate modulation. [ABSTRACT FROM AUTHOR]

A low-power transceiver for medical implant communication service is presented. The device consists of three subsystems, which perform wake-up signal reception, data-link binary frequency-shift keying (BFSK) reception, and transmission, respectively. A common antenna interface is reused in the three subsystems, reducing circuit complexity and number of external components. Super-regenerative architecture is used for wake-up reception, and gm-boosted common-gate stages are used to optimize receiver (RX) performance with low power consumption. The transmitter employs an all-digital frequency-locked loop to directly drive a class AB power amplifier. The transmitter can alternatively use an injection-locked power oscillator for lower bit rates and power consumption. The integrated circuit is designed and fabricated on a 0.18-\mu\m CMOS process. The wake-up RX achieves a -80-dBm sensitivity for a 50-kb/s signal and a 280-\mu\W dissipation. The BFSK RX achieves a -97-dBm sensitivity for a 75-kb/s signal and a 2-mW power consumption. Finally, the transmitter achieves an output power of -5 dBm for a power consumption of 2.9 mW. [ABSTRACT FROM AUTHOR]