TT Electronics launched two new ranges of SMD thick film chip resistors designed to optimise performance under pulse and surge conditions. With a value range of 1R0 to 1M0, the resistors provide surge protection in compact circuits where a small footprint size is critical to the design. TT Electronics’ PWC0603 and DSC0603 series are designed specifically to provide reliable operation under pulsed load conditions.
For both the PWC and DSC ranges the 0603 size is a new smaller version that is being added to both series. DSC resistors are double sided while the PWC are single, otherwise most parameters and features are common to both ranges.
Aimed at designers of power supplies, circuit breakers, remote sensor interfaces, defibrillators, and indeed any circuit types where pulses or surges are possible, the resistors are particularly suited to applications in the industrial, medical and instrumentation sectors. They provide enhanced product reliability by protecting circuits against occasional surges that may be generated by load switching or lightning strikes close to power lines.
For a 100-microsecond pulse, PWC0603 will take 10W, and the double sided DSC version withstands 20W peak power, while for both types the surge withstanding is 1.2/50 microseconds up to 500V. These figures result in enhanced reliability and reduced field failures.
In fact, TT Electronics’ PWC0603 and DSC0603 offer a surge withstand performance exceeding that of competing parts. Further enhancing reliability, the resistors feature optional anti-sulphur terminations.
In developing and manufacturing the resistors, TT Electronics uses proprietary laser trimming techniques that help to spread the generated heat evenly over the surface of the component. In the case of the double sided DSC0603, the addition of a second resistor film on the underside ensures that heat is spread evenly on both sides of the component.
Factors driving the demand for this type of product include the increased sensitivity of modern electrical systems to damage from high-energy surges, and the demand for more compact components to allow miniaturisation of host equipments.