1.5V CMOS current reference with extended temperature operating range

Traditional bandgap based current references have restricted temperature operating range due to the limited input common mode range of the feedback amplifier. This paper introduces a modified bandgap current reference that overcomes this limitation by placing a natural device (V/sub th/ /spl sim/ 0V) level shift stage between the amplifier and the bandgap. The circuit has been fabricated in a 0.25-/spl mu/m CMOS process. It generates a reference current of 5/spl mu/A with a temperature variation of 7% over an extended temperature range of -40/spl deg/C to 150/spl deg/C. The bandgap occupies approximately 170/spl times/80/spl mu/m/sup 2/ and draws 56/spl mu/A from a 1.5V supply.

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