A 4.5X Noise Improved Split-Resistance Currennt mode Bandgap with 18.4ppm/°C in 28nm CMOS

This paper presents a technique to limit the noise multiplication of operational amplifier used in the bandgap core without adding any extra component. This is achieved by shifting the resistor used in the emitter of low current density bipolar to its base. Further this resistor is combined with the existing CTAT resistor in the current mode bandgap reference. Also a high gain self-bias opamp was presented to minimize the systematic offset of the opamp leading to an improved accuracy. The proposed circuit is designed in TSMC 28nm CMOS technology and post-layout simulation results were performed. The targeted output voltage is 250mV and TC of 18.4ppm/ ^° C. The low frequency noise power spectral density (PSD) is 4.5 times lower compared to the convention architecture. Proposed architecture consumes 54.6µW power from 1V nominal supply and occupies an area of 3690 µm ² silicon area including decoupling capacitors.