SMD Current-Sense Resistors Operate To 275ºC

While most SMD current-sense resistors are limited to maximum operating temperatures of 155ºC to 170ºC, Stackpole’s CSS/CSSH series current-sense resistors feature a unique metal-plate technology that allows operation up to 275ºC (Fig 1). In addition, the CSS/CSSH series is the first current-sensing chip series that is rated for full-power operation up to 100ºC instead of 70ºC (Fig 2). For comparisons with existing devices, see products such as Stackpole’s CSR/CSRN Series, TT electronics IRC’s LR series, and KOA Speer Electronics’ SR73 series.

The higher temperature operation of the CSS/CSSH series allows engineers to use smaller chip sizes in motor control and power supply applications, or keep the same size part and reduce the overall heat generated by the power circuit. Package sizes range from a 1206 case rated at 0.5 W up to a 2728 case rated at 4 W (Table). Other specifications include TCRs ranging from 15 ppm to 50 ppm and tolerances down to 0.5%. Pricing varies with size, tolerance, and resistance value and ranges from $0.175 each to $0.50 each in full-reel quantities. 

Fig 1. A metal-plate technology allows the CSS/CSSH series current-sense resistors to operate up to 275ºC.

Fig 2. While most surface-mount current-sense resistors begin derating at 70ºC, the CSS/CSSH series deliver full power up to 100ºC.

Table. Package sizes and power ratings