A 4.4-mA ESD-Safe 900-MHz LNA With 0.9-dB Noise Figure

A 900-MHz 1.2-V 4.36-mA low-noise amplifier (LNA) with a minimum of 0.92-dB noise figure (NF) at 868 MHz, -12-dBm IIP3, with one inductor (external) is demonstrated. The circuit achieves narrowband input matching on a wideband LNA without inductive degeneration. A new half-cascoding technique is used to improve the input matching (S
₁₁
) while simultaneously achieving sub-1-dB NF performance. The 0.13-μm CMOS LNA is fabricated with embedded electrostatic discharge (ESD) protection diodes that add 60 and 80-fF loads at the RF input and output ports. At 868 MHz, the packaged LNA has a measured input return loss (S
₁₁
) of -18 dB and the transmission gain (S
₂₁
) of 14.2 dB. At 900 MHz, the LNA has a measured NF of 0.98 dB. The LNA (excluding the buffer) occupies an area of 0.047 mm
²
. The chip passes the human body model (HBM) test with an ESD zap of 2.5 kV within 10% margin of its prezap I-V characteristics, under JEDEC standards. Multiple packaged chips were characterized with no perceptible difference in performance, indicating a robust design.