Ametherm Thermistor Delivers 680V rating for welding equipment, plasma cutters



PTC circuit protection thermistor

Ametherm announced a new PTC circuit protection thermistor with an industry-high voltage rating for inrush current limiting and overcurrent protection in applications such as welding equipment and plasma cutters with extremely high voltages from 480 V to 930 V.

The new MCL20 500100-A thermistor released today features a 680 V voltage rating and handles a maximum inrush current of 20 A at maximum peak voltage. The device offers resistance at 25 °C of 50 Ω with a tolerance of 20 %, a dissipation constant of 55.0 mW/°C, a heat capacity of 5.45 J/°C, and a thermal constant of 62 s. The thermistor operates over a wide temperature range of -50 °C to +150 °C.

The radial-leaded MCL20 500100-A offers easy PCB mounting. With a 19 mm diameter, 9 mm maximum profile, and 7.8 mm 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.

"The MCL20 500100-A can withstand hundreds of hits of maximum inrush current without degrading," said Eric Rauch, president and CEO at 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."

The MCL20 500100-A PTC thermistor is available direct or through distributors such as Mouser. Samples and production quantities of the device are available now, with factory lead times of seven weeks. Volume pricing for U.S. delivery starts at $2.60 per piece in 1,000-piece quantities.