Tl431 is a precision adjustable reference power supply circuit , a good regulation characteristics and spirit. Live voltage value is set , the output voltage can be set continuously between vref to 40v Tune with 0.27o typical dynamic output impedance of the circuit in many applications can replace sensor transistor. Feature:programmable output voltage up to 40v Low dynamic output impedance , typically 0.27o Cathode current capacity of 0.1ma-100ma Full temperature range of temperature characteristics flat , typically 50ppm / ? Over the entire operating temperature range of the rated operating temperature can be compensated Low output noise voltage To-92