A 4 μW dual-modulus frequency divider with 198 % locking range for MICS band applications

This paper presents the design and performance of an ultra-low-power 4/5 frequency divider based on a CMOS ring oscillator. Measurements show a 198 % locking range (6 MHz–1.3 GHz) for both division ratios at room temperature, covering the MICS band and 433 and 915 MHz ISM bands while consuming only 4.07 μW from a 1 V supply at 400 MHz. The wide locking range and low power consumption makes it very suitable for ultra-low-power wireless systems. The divider is fabricated in a 90 nm CMOS process and occupies 45 μm² of area.