A CMOS 180 nm digitally adaptable bandgap voltage reference with integrated 7-bits voltage configurator for 5G wireless communication system

Abstract

This paper proposes an adaptable bandgap voltage reference (BGR) with a 7-bits voltage configurator (7BVC) for 5G wireless communication integrated circuits. The 7BVC-BGR is designed and fabricated in a CMOS 180 nm process. The core BGR is integrated with 2-stage operational amplifiers (op-amp), buffers, and 7-bits digital switches. The 7BVC configures a set of current addition bits (A₃-A₀) and current subtraction bits (S₂-S₀) that control the total current flow into the load resistor. By controlling the seven digital bits, the 7BVC is capable of generating 128 states of voltage references (V_REF), in which 92 states are optimum in its temperature coefficient (TC) and line regulation (LR). Supplied with a voltage headroom of 3.3 V, the 92 usable states provide a measured V_REF that varies from 0.34 to 1.52 V. The TC and LR achieved by the varying V_REF are 2.51 to 15.86 ppm/°C and 0.0089 to 0.0289 %/V, respectively. The power-supply-rejection-ratio (PSRR) achieved varies from -83.1 to -95.1 dB. The noise performance at 100 Hz varies from 4.9 to 19.8 µV/√Hz across the V_REF configured. Also, the 7BVC-BGR can be reconfigured to improve the temperature coefficient (TC) by performing curvature correction and minimizing the V_REF variations between samples. The 7BVC can be adjusted with various digital bit configurations to accommodate variations in TC and V_REF values across samples. The proposed 7BVC-BGR exhibits consistent and reliable performance throughout testing and validation, placing it at the same level as the most advanced BGRs.