A 192 pA current reference is proposed for ultra-low-power applications. The sub-threshold design based circuit employs three-transistor-regulators to provide a CTAT (complimentary-to-absolute-temperature) source to gate voltage, to a PMOS device that minimizes the temperature variation of the reference current. Consistent performance across process variations is achieved through digital trimming and body bias control. A temperature coefficient (TC) of 542~ppm/°C is attained at nominal process with a minimum and maximum TC of 350~ppm/°C and 729~ppm/°C, respectively, across all process corners. The circuit operates at a worst case minimum supply voltage of 700 mV and the power consumption is 1.06 nW at the nominal process and temperature. The same architecture is reused for a reference current of 87.7~nA, which improves the TC to 91.2~ppm/°C. The circuit is designed in standard 0.18um CMOS technology.