Abstract
In this paper, we present a detailed analysis of VCOs using a capacitively degenerated negative resistance cell. The negative resistance cell using capacitive degeneration has a higher maximum attainable oscillation frequency and a smaller equivalent shunt capacitance when compared to the widely used cross-coupled negative-gm cell. These properties are of particular interest for the design of high-frequency and/or wide tuning range VCOs. The negative resistance provided by a traditional capacitively degenerated negative resistance cell is lower than that provided by a cross-coupled negative-g m cell. We present an active capacitive degeneration topology that overcomes this limitation. To validate this circuit topology we use two test vehicles. The first test vehicle is a 5.3 GHz VCO designed in a 0.25 μm CMOS technology and the second test vehicle is a 20 GHz VCO designed in a 0.25 μm BiCMOS technology. Measurement and simulation results from both test vehicles effectively demonstrate the efficacy of the capacitive degeneration technique.
Original language | English (US) |
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Pages (from-to) | 319-351 |
Number of pages | 33 |
Journal | International Journal of High Speed Electronics and Systems |
Volume | 15 |
Issue number | 2 |
DOIs | |
State | Published - Jun 2005 |
Keywords
- Analog integrated circuits
- BiCMOS integrated circuits
- Capacitive degeneration
- High-frequency LC oscillators
- Negative resistance cell
- Voltage-controlled oscillators