Current-sensing resistor combines precision, surface mounting
By Bill Schweber -- EDN, November 13, 2003
Your choice of current-sensing resistor is sometimes more critical than you think at first glance, because errors and drift in that component’s nominal resistance can have large effects on your feedback or control loop’s performance. You may want to consider the CSM2512 and CSM3637 foil resistors from Vishay Intertechnology (Picture). They use an all-welded construction and bulk-metal element to provide temperature coefficient of resistivity as low as ±15 ppm/°C, along with long-term stability and tolerance as tight as ±0.1%.
The 1W-rated CSM2512 is available in resistance values of 3 to 200 mΩ, and the CSM3637 is rated at 3W from 2 to 10 mΩ and 2W from 10 to 200 mΩ . The devices measure 6.35×3.175 mm (2512 size) and 9.14×9.4 mm (3637 size), respectively, for these resistors, which feature four-terminal (Kelvin) connection and sell for approximately $2.75 each, depending on tolerance and quantity.
Vishay Intertechnology Inc, www.vishay.com.
