A Frequency Synthesizer for Mode-1 MB-OFDM UWB applications

摘要

A frequency synthesizer for Mode-1 MB-OFDM UWB applications is realized in 65nm CMOS. By using a delay-locked loop (DLL) and the proposed multiply-by-two circuit, the frequency synthesizer achieves the in-band spur of-40dBc for the three-band operation. The proposed multiply-by-2 circuit realizes the quadrature signals, and its input signals do not need the 50% duty cycle. A modified current-starving cell in a DLL is also proposed to reduce the supply noise sensitivity. The measured switching time from 3.342GHz to 4.488GHz is around 1.1ns. The area is 1.25×1.175mm~2 with pads and the power is 19.2mW for 1.2V supply.