IEICE Trans - A Design of 0.7-V 400-MHz Digitally-Controlled Oscillator

A Design of 0.7-V 400-MHz Digitally-Controlled Oscillator

Jungnam BAE
Saichandrateja RADHAPURAM
Ikkyun JO
Takao KIHARA
Toshimasa MATSUOKA

Publication
IEICE TRANSACTIONS on Electronics Vol.E98-C No.12 pp.1179-1186
Publication Date: 2015/12/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E98.C.1179
Type of Manuscript: PAPER
Category: Integrated Electronics
Keyword:
digitally-controlled oscillator, ΔΣ modulator, dynamic element matching, data-weighted averaging, clocked averaging, CMOS, MICS,

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Summary:
We present a low-voltage digitally-controlled oscillator (DCO) with the third-order ΔΣ modulator utilized in the medical implant communication service (MICS) frequency band. An optimized DCO core operating in the subthreshold region is designed, based on the g_m/I_D methodology. Thermometer coder with the dynamic element matching and ΔΣ modulator are implemented for the frequency tuning. High frequency resolution is achieved by using the ΔΣ modulator. The ΔΣ-modulator-based LC-DCO implemented in a 130-nm CMOS technology has achieved the phase noise of -115.3 dBc/Hz at 200 kHz offset frequency with the tuning range of 382 MHz to 412 MHz for the MICS band. It consumes 700 µW from a 0.7-V supply voltage and has a high frequency resolution of 18 kHz.