SMT resistors approach wirewound performance

Rugged surface mount devices are specifically designed for surge/pulse applications and for circuits subject to extreme thermal cycling.

Providing design engineers with rugged surface mount devices specifically designed for surge/pulse applications and for circuits subject to extreme thermal cycling, TT Electronics IRC Wire and Film Technologies Division offers two versions of its popular cylindrical surface mount resistors.

Designated the HSF Series and SMC Series, respectively, the cylindrical surface mount resistors approach wirewound performance levels in each area while providing OEMs with significant cost savings.

Both devices utilise IRC's MetalGlaze thick film resistive elements on cylindrical ceramic substrates, which provide better heat dissipation, improved solderability and improved surge/pulse capabilities.

The two series are optimised for different applications.

The HSF Series features an unspiralled thick film element that offers three times the surge rating of IRC's standard CHP Series, or as much as 10 times the rating of a conventional flat chip 2512 component.

Designed to fit within the footprint of a standard 2512 chip, the HSF Series saves a significant amount of board space versus a comparable rated wirewound device.

The HSF Series resistors feature a power rating of 1W at 70C and a working voltage of 350V.

Resistance values of 5.9, 11, 27, 68 and 270ohm are offered, with a tolerance of +/-10%, and TCRs to +/-50ppm/C.

Maximum operating temperature is +150C.

IRC will also produce devices in custom resistance values to meet customer requirements.

The SMC Series resistors are designed to provide maximum thermal compliance for use in applications that are subject to extreme temperature cycling.

Metal caps fitted on the terminals of the cylindrical resistor body give the SMC Series devices exceptional thermal compliance, relieving stresses created from the TCE (thermal coefficient of expansion) mismatch between the ceramic component and the FR4 circuit board.

Designed to fit within industry standard 2512 and 3610 footprints, the SMC Series devices are ideal for automotive, power supply and industrial applications that require a surface mount resistor with superior surge and thermal characteristics.

The SMC Series resistors have a maximum power rating of 1W at 70C for the 2512 package and 2W at 70C for the 3610 size.

Resistance range is 1ohm to 2.0Mohm, with standard tolerance to +/-5%, and TCRs to +/-50ppm/C.

Maximum operating temperature is +150C.

IRC will also produce devices outside these specifications to meet customer requirements.

Typical pricing for the HSF and SMC Series resistors is approximately $0.18 each in quantities of 10,000.

Lead time is from stock to 4 to 6 weeks.

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