Abstract
Characteristics of symmetrical spiral inductor in differential mode is studied and optimized in this work. The characteristics of interest include inductor value, quality factor, peak frequency and self-resonance frequency. Both single-layer and double-layer inductor using top metals are characterized. Inductor excited in differential mode and single-ended mode are characterized for comparison. The optimized symmetrical spiral inductors are fabricated in standard digital 0.35 μm CMOS process. Experimental results show 60-100% improvement of quality factor and peak frequency, meanwhile 10-20% improvement of self-resonance frequency by exciting the symmetrical spiral inductors in differential mode compared with single-ended mode. To further validate the characterized inductor, the differential spiral inductors are adopted in optimizing low power and low phase noise fully integrated 2.4 GHz voltage-controlled oscillator (VCO). The designed VCO achieved phase noise of more than -105 dBc/Hz at 100 kHz offset with approximately 4.5 mA at 3.0 V supply.
Original language | English |
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Pages (from-to) | 1643-1650 |
Number of pages | 8 |
Journal | Solid-State Electronics |
Volume | 48 |
Issue number | 9 |
DOIs | |
State | Published - 09 2004 |
Externally published | Yes |
Keywords
- CMOS
- Differential mode
- RF
- Single-ended mode
- Symmetrical spiral inductor
- VCO