A 15.4 ppm/°C Improved Current Mode Bandgap with 0.9 V Supply in 28 nm CMOS

Conventional current-mode bandgap reference (BGR) (Banba) architecture has several issues, like multiple oper-ating points and the need for PTAT current. This paper presents a modified low-voltage Banba architecture using the resistors technique to produce the sub-1 V output. In the Banba BGR, the opamp's offset impacts the output temperature coefficient (TC) due to the low PTAT gain. A high-gain self-bias opamp has been proposed in this research to reduce its effects on BGR TC. The maximum operating voltage of the BGR is analyzed and strongly depends on the bias current; hence, a very low current is used. Post-layout simulations of the proposed BGR are carried out using 28 nm CMOS technology. A target output voltage is 250 m V, and 15.4 ppml° C is the TC. The proposed BGR output has a standard deviation of 1.3mV based on 200 Monte Carlo simulations. The proposed BGR, with decoupling capacitors included, takes up 3690 µm
²
of silicon area and uses 11.7 µW of power from a nominal supply of 0.9V. Compared to conventional and other state-of-the-art BGRs, the proposed BGR has a superior Power Supply Rejection Ratio (PSRR) (around the loop bandwidth) by an increase of 12 dB.