A 4GHz low power glitch-free phase-switching divide-by-15/16 prescaler in 0.18-µm CMOS

This paper presents a low power glitch-free dual-modulus (15/16) prescaler based on the phase-switching for Ultra-Wide Band (UWB) transceiver. An inherently glitch-free phase-switching prescaler is realized by the adoption of a reverse switching sequence without any additional complicated circuit. A simplified model of the source coupled logic (SCL) structure is proposed to optimize the power of the divide-by-2 divider. Followed by the first divide-by-2 stage, a synchronous divide-by-4 stage is used to generate eight 45°-spaced signal, which further decreases the operating frequency and the phase sequence is determined. Fabricated with SMIC 0.18μm CMOS technology, the proposed prescaler can operate from 2.8GHz to 5.8GHz while consuming 6.5mA (including test buffers) from a 1.8V voltage. The core area is 0.33mm×0.33mm.