By Topic

A 32nm CMOS all-digital reconfigurable fractional frequency divider for LO generation in multistandard SoC radios with on-the-fly interference management

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

5 Author(s)

A VCO used in a PLL inside a wireless transceiver can be sensitive to interference from other radio circuitry (e.g. on-chip PA), components of the SoC system (e.g. clocks and their harmonics) and nearby radios. To prevent VCO pulling by the PA, fractional dividers can be used to offset the VCO frequency (fVCO) with respect to the PA. Multistandard radios covering, for example, WiFi 2.4 to 2.5GHz and 5 to 5.8GHz, and WiMAX 2.3 to 2.7GHz and 3.3 to 3.8GHz, may require multiple VCOs and/or multiple fractional dividers to cover all bands [1], resulting in complexity and area overhead. This paper proposes a versatile reconfigurable fractional divider capable of covering the above standards with a single VCO with 20% tuning range. The divider is all-digital, hence scaling-friendly, and uses digital calibration to eliminate the need for filtering and area-intensive inductors. The versatility afforded by the reconfigurable fractional divider allows for the transceiver's LO generation (LOG) frequency plan to be adjusted on-the-fly. This can avoid VCO pulling from interferers which may not be known a-priori, like SoC-CPU clocks that are adjusted dynamically for best performance.

Published in:

2012 IEEE International Solid-State Circuits Conference

Date of Conference:

19-23 Feb. 2012