New 680V thermistor targets welding equipment and plasma cutters

Ametherm has introduced a new PTC circuit protection thermistor with an industry-high voltage rating for inrush current limiting and over-current protection in applications such as welding equipment and plasma cutters with extremely high voltages from 480V to 930V. The MCL20 500100-A features a 680 voltage rating and handles a maximum inrush current of 20A at maximum peak voltage. The device offers resistance at 25C of 50ohm with a tolerance of 20%, a dissipation constant of 55.mW/C, a heat capacity of 5.45 J/C, and a thermal constant of 62s. The thermistor operates over a wide temperature range of -50C to +150C. The radial-leaded MCL20 500100-A offers easy PCB mounting. With a 19mm diameter, 9mm maximum profile, and 7.8mm lead spacing, the thermistor provides designers with a more compact and cost-effective alternative to combining a power resistor, relay, and timer on one circuit to achieve the same functionality. The RoHS-compliant device is available with straight leads and outside or inside kinked leads, says the company. "The MCL20 500100-A can withstand hundreds of hits of maximum inrush current without degrading," said Eric Rauch, president and CEO, Ametherm. "The device offers a short reset time, and as a PTC thermistor a quick reset will not result in a large inrush current, as its resistance is already at a high state. The result is extremely high reliability and stability in high-voltage applications, all while saving board space."