A 2.4 GHz ZigBee Receiver Exploiting an RF-to-BB-Current-Reuse Blixer + Hybrid Filter Topology in 65 nm CMOS

A 2.4 GHz ZigBee receiver unifying a balun-LNA-I/Q-mixer (Blixer) and a baseband (BB) hybrid filter in one cell is fabricated in 65 nm CMOS. Without any external components, wideband input matching and passive pre-gain are concurrently achieved via co-optimizing an integrated low-Q network with a balun-LNA. The latter also features active-gain boosting and partial-noise canceling to enhance the gain and noise figure (NF). Above the balun-LNA are I/Q double-balanced mixers driven by a 4-phase 25% LO for downconversion and gain-phase balancing. The generated BB currents are immediately filtered by an IF-noise-shaping current-mode Biquad and a complex-pole load, offering first-order image rejection and third-order channel selection directly atop the Blixer. Together with other BB and LO circuitries, the receiver measures 8.5 dB NF, 57 dB gain and -6-dBm IIP3
_out-band
at 1.7 mW power and 0.24 mm
²
die size. The S
₁₁
-bandwidth (<;-10 dB) covers 2.25 to 3.55 GHz being robust to packaging variations. Most performance metrics compare favorably with the state-of-the-art.