High-Performance Clock Generation and Distribution

Energy-Efficient RF and High-Speed Integrated Circuits

As both the data rate and system complexity of communications and computing increase, power consumption becomes increasingly critical, particularly in high-performance microprocessors, mobile wireless communications, and sensor applications. While advances in semiconductor materials and devices can change the fundamental limits on the power consumption such as gate leakage, new circuit techniques are needed to approach these limits, and more importantly, to enable the use of low-cost main-stream process technologies such as CMOS to achieve high power efficiency. In this research thrust, we explore new circuit technologies to significantly lower the power consumption of some critical building blocks in RF systems and high-speed digital VLSIs. Our approach is to leverage the nonlinear characteristics of active devices, and control the power spectrum of signals, in addition to conventional RF techniques such as power matching. In particular, we are pursuing a circuit technique, injection locking. Current projects include injection-locked oscillators (ILO) and injection-locked frequency dividers (ILFD).

18GHz Divide-by-3 Injection-Locked Frequency Divider
Application: PLL, frequency synthesizer, radar
Innovation: differential mixing, harmonic processing
Technology: 0.18um standard digital CMOS
Locking range: 6%, 19% extended
Power dissipation: 4.6mW
Phase noise: 9dB down from input (ideal)

19GHz Divide-by-2 Injection-Locked Frequency Divider
Application: PLL, frequency synthesizer, radar
Innovation: shunt-peaking locking-range enhancement
Technology: 0.35um CMOS
Locking range: 17%
Power consumption: 1mW
Phase noise: 6dB down from input (ideal)