News and New Products

Resistor array divides, so design conquers ratio needs

By Bill Schweber -- EDN, 4/28/2005

The venerable reistor divider is still a staple of high-precision analog circuits, because it enables measurement architectures that depend not on absolute component values, but only on their ratios, which are more stable. BI Technologies has put a series-connected, two-resistor divider into a three-lead SOT-23 package, forming a precision voltage divider (Picture). The ultrastable resistors of the SSI series are available in standard ratios of 1-to-1, 1-to-4, and 1-to-10. Tolerances are as tight as 0.1%, and the more critical temperature coefficient is ±25 ppm/°C with tracking tolerance better than ±5 ppm/°C.

BI fabricated the resistors using nichrome thin-film technology on a silicon substrate. The device’s size lets designers place it close to the circuit area of interest, thus, according to Mike Torres, application engineer and product marketing manager for BI, “eliminating the need for the long traces and complex routing schemes required for large networks.” The SSI series is also available with three resistors in a network in a four-lead SOT-143 package. Prices begin at 30 cents (10,000).

BI Technologies, www.bitechnologies.com.