67ppm/°C, 66nA PVT Invariant Curvature Compensated Current Reference for Ultra-Low Power Applications

This work presents a highly accurate current reference of 66nA for ultra-low power applications. A very low figure-of-merit (FOM) of 1.3501ppm/°C
²
is achieved on consuming a minimal quiescent current of 199.37nA. To cancel out process variations, the current subtraction technique is employed and a β-multiplier is used to compensate for mobility (μ) and threshold voltage (V
th
). In addition, curvature compensation technique backed by PTAT and CTAT current cancellation is adopted to attain a lower temperature coefficient (TC). Hence, an imperceptible variation of accuracy with temperature and supply variations across all process corners is attained. An adopted trimming scheme further minimizes the overall process spread to ±1.515% without compromising on accuracy. Accordingly, a TC of 67.04ppm/°C over a wide temperature range of −50° C to 100° C is obtained. Furthermore, 1.413%/V line sensitivity (LS) in the supply range of 1.38V to 3V is observed. Low power consumption of 275.13nW@1.38V facilitates its use in high-performance low power applications.