An extended family

has extended its family of thick film power resistors with the introduction of 30-W, 50-W and 100-W devices in industry-standard TO220 and TO247 packages.

The resistors use a ceramic package design (with no metal tab) for direct-mounting on heatsinks, and feature an exceptionally low inductance of less than 0.1µH, suiting them for use in power conversion and control applications in a wide variety of industries.

The new Vishay Sfernice devices are available in a wide range of resistance values, from 0.010 Ohms to 550 kohms for the LTO 30 and LTO 50 families, and from 0.015 Ohms to 1 Megohm for the LTO 100. All of the devices have a temperature coefficient of 150ppm/ degrees C for values above 0.5 Ohms. Their compact, low-profile, direct-mounting package design is said to improve heat dissipation and reduces space on printed circuit boards.

The LTO resistors are designed for use in pulse-loading applications, as snubber or bleeder resistors, and in a variety of other high-power equipment such as uninterruptible power supplies (UPS), power conversion for traction and industrial drives, and in medical, automotive, and industrial control environments. The resistors use an optimised process of printed thick film technology on an alumina substrate to achieve tolerances as low as +/- 1%, and up to +/- 10%.

All of the resistors are compatible with tin/lead and lead-free soldering processes, allowing use by all assemblers transitioning to lead-free processes to meet incoming legislation and voluntary environmental manufacturing codes.

In addition, all devices comply with EU directives on vehicle end of life, including 2000/53/EC End of Vehicle Life Directive (ELV) and 2000/53/EC Annex II to End of Vehicle Life Directive (ELV II). All devices also meet 2002/95/EC Restriction of the use of Hazardous Substances Directive (RoHS) and 2002/96/EC Waste Electrical and Electronic Equipment Directive (WEEE).

Samples and production quantities of the new Vishay Sfernice LTO resistors are available now, with a lead-time of eight weeks for larger orders.