A 2.4 GHz CMOS diversity receiver having a soft‐start regulator for wake‐up

Abstract

An improved diversity receiver having a new regulator for stable power supply in a 0.18 lm CMOS technology is presented. The regulator with soft-start is implemented to eliminate the battery damages at initial power-up. To reduce the external components, two switches for antenna diversity are integrated in front of LNA on the chip. A stacked inductor technique is adopted to reduce the chip area. The simulation and measurement results show that the soft-start time of the regulator can be controlled by a variable resistor from 200 lS to 6.2 mS. The front-end (LNA and mixer) can achieve a voltage gain of 33.5 dB, a noise figure (NF) of 3.8 dB, and 23 dB of the isolation between antennas when consuming 3.9 mW with a 1.8 V power supply. The NF includes the loss of a BALUN, BPF, and switches.