An optimized DCO with modified binary-weighted DCTLs based hybrid tuning banks for an E-band DPLL

Area of Science:

• Electrical Engineering
• Integrated Circuit Design

Background:

• Millimeter-wave (mmWave) systems require efficient and compact frequency sources.
• Traditional digital controlled oscillators (DCOs) face challenges in balancing chip size, tuning resolution, and phase noise.

Purpose of the Study:

• To present an optimized millimeter-wave DCO in a 40-nm CMOS process.
• To improve tuning precision, die size, and phase noise performance.
• To achieve a better compromise between chip size, resonant frequency, tuning resolution, and phase noise.

Main Methods:

• Utilized modified binary-weighted digitally controlled transmission lines (DCTLs) for coarse and medium tuning.
• Replaced the lowest-weight bit of DCTLs with switched capacitors to enhance medium tuning.
• Implemented a binary-weighted switched capacitors array with a low-coupling transformer for fine tuning.

Main Results:

• Achieved a tuning range of 76-81 GHz.
• Reduced the overall length of coarse and medium tuning modules by 34.4% (from 122µm to 80µm).
• Obtained a figure of merit (FoM) of -190.52 dBc/Hz with a die size of 0.12 mm².

Conclusions:

• The optimized DCO design offers a superior balance of performance metrics.
• The modified DCTLs and switched capacitor arrays contribute to reduced complexity and improved efficiency.
• This work provides a compact and high-performance mmWave DCO suitable for advanced applications.