E‐band broadband digital controlled phase‐inverting variable gain amplifier in 65‐nm CMOS

Abstract

This letter reports an E-band phase-inverting variable gain amplifier in 65-nm complementary metal-oxide-semiconductor (CMOS) technology. A fractional bit based structure with replica cells is proposed to minimise the phase error and ensure the tuning accuracy between different gain modes. This structure has 9-bits digital-controlled amplifiers and allows 180° phase shifting. The implemented phase-inverting variable gain amplifier achieves 16 dB tuning range and 0.5 dB tuning step at 80 GHz. The root mean square (RMS) gain and phase errors across −3 dB bandwidth (i.e. 72–87 GHz) are less than 0.3 dB and 2.7°, respectively. The phase-inverting variable gain amplifier consumes 8 mW at 1 V supply voltage.