The Design of Broadband LNA with Active Biasing based on Negative Technique

Abstract

In this paper, we present a broadband LNA based on an improved negative feedback design. With the adjustment of the negative feedback inside the chip, the LNA achieves a planarized gain and an optimized operating bandwidth from 0.2 GHz to 4 GHz. To guarantee the good performance stability under severe environments, an active biasing is used inside the chip. As a result, effective compensations for the fluctuation of the supply voltage and the temperature variation are achieved. The LNA chip uses GaAs pHEMT at 0.25-um technology node and SIP package technique. This broadband LNA shows good performances, including gain of about 15 dB, gain flatness of less than 1dB, and noise figure of less than 1.5 dB. The packaged size of this broadband LNA is 3 mmÍ3 mmÍ1 mm.