300µΩ Integrated Sense Resistor

Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of a new power and energy monitoring product (model: LTC2947) for 0V to 15V DC power supply rails.

Most power and energy monitoring ICs use external sense resistors for current measurement. However, selecting an appropriate sense resistor is not straightforward. This is particularly challenging when handling high currents or when the sense resistor generates significant heat, occupying substantial board area and significantly affecting measurement accuracy.

The LTC2947 integrates a 300µΩ temperature-compensated sense resistor, eliminating the burden of sense resistor selection for users, and provides a simple 24mm² solution capable of energy readings with 1.2% accuracy at maximum ±30A. When measuring a 30A full-scale current, the voltage drop across the LTC2947's integrated sense resistor is only approximately 9mV, resulting in approximately 0.25W power dissipation for 30A rail measurement and approximately 10mW for 6A rail measurement. Beyond these low thermal dissipation characteristics, the LTC2947 offers high dynamic range (DR) with an offset as low as 6mA (or 1.8µV).



Three integrated delta-sigma ADCs (Δ∑ ADC) and one internal or external precision time base (crystal or clock) enable accurate measurement of multiple parameters including current, voltage, power, charge, energy, temperature, and time. All digital readings, including minimum and maximum values, are stored in registers accessible through either I2C or SPI interface selection.

When a measured value exceeds a preset alert threshold, an alert signal is communicated to the host, eliminating the burden of polling. The LTC2947 provides access to all parameters necessary for accurate evaluation and management of board-level energy consumption, and its rail-to-rail operating range is ideal for monitoring current levels in short-circuit or blackout situations without additional circuit configuration.

Tailored for commercial and industrial temperature ranges, the LTC2947 is available in a 32-lead 4mm x 6mm QFN package, with pricing starting at $5.95 per unit for orders of 1,000 pieces. Samples and evaluation boards are available for purchase through online channels or Linear Technology regional sales offices.