A 2.4-GHz Low-Flicker-Noise CMOS Sub-Harmonic Receiver

A 2.4-GHz low-noise sub-harmonic direct-conversion receiver (SH-DCR) is demonstrated using standard 0.18-μm CMOS technology. Deep-n-well vertical-NPN (V-NPN) bipolar junction transistors (BJTs) are employed to solve the flicker noise problem in CMOS process. Design optimization of a power-constrained noise-impedance-matched low-noise amplifier (LNA) with the effect of lossy on-chip inductors is fully discussed in this paper. A multi-stage octet-phase polyphase filter is analyzed in detail and implemented to generate well balanced octet-phase LO signals. As a result, the demonstrated receiver achieves 51-dB voltage gain and 3-dB noise figure with flicker noise corner less than 30 kHz when RF = 2.4 GHz. The I/Q amplitude/phase mismatch is below ±0.2 dB/±1^°, respectively, covering from 2.35 to 2.6 GHz. The dc current consumption is 5 mA at a 1.8-V supply.