A 4.0-mW 2-Mbps Programmable BFSK Transmitter For Capsule Endoscope Applications

A low power binary frequency shift keying (BFSK) transmitter has been proposed for capsule endoscope applications. The transmitter IC includes a low drop-out (LDO) regulator, a crystal oscillator, a class-E power amplifier (PA) and a frequency synthesizer with dual control loops. The parameters of the transmitter, including carrier frequency, frequency deviation and etc., can be set by a serial 3-wire interface. The transmitter IC is implemented in TSMC 0.35 mum CMOS process occupies 3.47 mm
²
and can be fabricated in a fully digital process. For supply voltage down to 1.85 V, and the transmitter center frequency set to 416 MHz, a maximum data rate of 2 Mbps can be achieved with -24 dBm output power and only 4.0 mW power consumption