Low power synthesizer for wireless tranceivers in medical applications

In this paper, a dual loop CMOS phase locked loop (PLL) synthesizer with a wide operating frequency range for wireless low power medical systems is presented. A new low power, high speed, low noise phase frequency detector has been designed. The self-adjusting charge pump is a single-ended drain switching circuit and wide swing cascode current mirrors have been implemented to improve the output compliance. The oscillator is an LC-voltage controlled oscillator (VCO) with external inductor, integrated PMOS varactors & poly-poly caps for fine and coarse frequency tuning respectively. Low swing current mode/differential pair logic has been used to design part of the multi-modulus divider. The 2^nd loop is a digital implementation that performs the frequency locking sequence. The typical oscillator tuning range is 808’937.6MHz. The total typical current consumed on a 1V battery is 2.58mA. The settling time is ≪1ms.