A CMOS current reference circuit has been developed in 0.35-μm CMOS process. The circuit consists of a voltage reference circuit, a noninverting amplifier, and an output MOS transistor. The circuit generates a reference current independent of temperature and process variations. Temperature- and process-compensation were achieved by utilizing the zero temperature coefficient bias point of a MOSFET. Theoretical analyses and experimental results showed that the circuit generates a quite stable reference current of 18.4 μA on average. The temperature coefficient, load sensitivity, and process sensitivity (σ/μ) of the circuit were 46-ppm/σC, 1.5%/V, and 4.4%, respectively. The circuit can be used as a current reference circuit for high precision analog circuit systems.
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