Closed Form Expression of Input Matching of a Wideband Single-Ended to Differential LNA

A closed-form expression of the input-matching of a single-ended to differential wideband low noise amplifier(LNA) is derived in the paper. The LNA architecture uses a common-source topology with resistive feedback to provide wideband input matching. The LNA is considered with and without its package parasitics to show the difference in its $S_{11}$. The closed-form expression shows excellent agreement with post-layout simulated values of input-matching of the LNA designed in UMC 65-nm LP-CMOS process. The $S_{11}$ remains below −10 dB over 1 kHz-3 GHz with a minimum noise figure of 3.45 dB and a maximum gain of 29.9 dB.