Compact Extended Industrial Range CMOS Current References

This paper presents two new compact current reference circuits for use in extended industrial range from -45 degrees C to 125 degrees C. The first reference circuit implements very simple first order correction. The circuit parameters can be obtained by relatively simple calculations. The circuit is well suited for generation of currents equal to several mu A. The measurement results of two realizations for the generation of 1 mu A and 24 mu A currents were performed. The circuits achieve a competitive temperature compensation of < 200 ppm/degrees C in the wide operating temperatures range from -45 degrees to 125 degrees C. The second reference uses more advanced second order correction. The circuit was also verified by design and measurement of 230 nA current reference. Ten samples were measured through the extended industrial temperature range of -45 degrees to 125 degrees C. The minimum measured temperature coefficient value is 221 ppm/degrees C with a median value of 669 ppm/degrees C. All test circuits were designed in standard 0.35 mu m CMOS technology of AMS.