ST LM317MDT-TR

The LM217M/LM317M are monolithic integrated circuits in TO - 220 and DPAK packages, used as positive adjustable voltage regulators. They are designed to supply a load current with an output voltage adjustable over a 1.2 to 37V range. The LM217M/LM317M provide an internal reference voltage of 1.25V. The output voltage VO is given by VO = VREF (1 + R2 / R1) + IADJ R2. The devices were designed to minimize the term IADJ (100 µA max) and to maintain it very constant in line and load changes. Usually, the error term IADJ × R2 can be neglected. Since the LM217M/LM317M devices are floating regulators and "see" only the input - to - output differential voltage, supplies of very high voltage with respect to ground can be regulated as long as the maximum input - to - output differential is not exceeded. Furthermore, programmable regulators are easily obtained and, by connecting a fixed resistor between the adjustment and output, the devices can be used as a precision current regulator.