A PVT-Robust Analog Baseband With DC Offset Cancellation for FMCW Automotive Radar

Abstract

This paper presents a process-voltage-temperature (PVT)-robust analog baseband with DC offset cancellation (DCOC) for automotive radar applications. The baseband is composed of three stages of programmable gain amplifier (PGA) and an embedded fifth-order Butterworth filter. A novel embedded Gm-cell based DCOC feedback loop is proposed to achieve fine DC offset rejection and a low high-pass the cut-off frequency with an economic chip area. The proposed embedded Gm-cell based DCOC feedback topology is capable of improving gain error and loop stability simultaneously. Besides, a constant overdrive biasing technique is proposed to strengthen PVT robustness. Implemented in 65-nm CMOS technology, the measured results show that the analog baseband can provide a programmable gain range from 18.2 to 70.6 dB with 5.8 dB per step with a gain error of <;0.2 dB, while the 1-dB bandwidth range is from 200 kHz to 10 MHz. An OIP3 of 7.8 dBm and an input referred noise (IRN) of 15.8 nV/√Hz are obtained. The gain deviation is lower than 2.2 dB across all PVT corners. The core circuit consumes a dc power of 6 mW from a 1.2-V supply and occupies a chip area of 0.1 mm2.

Keywords

• Analog baseband
• automotive radar
• DC offset cancellation (DCOC)
• filter
• process-voltage-temperature (PVT)-robust
• programmable gain amplifier (PGA)