Current sense resistors’ smaller packages meet mobile form factors
Metal foil current sense resistors in the CFN series by Bourns are now available in 0402 and 0603 package sizes. Bourns has also added a low TCR option of ±50 parts per million (ppm) per degrees C in the 0603 and larger package sizes.
Bourns claims that its metal foil technology construction enables the new current sense resistors to provide low TCR, low inductance, low noise, excellent reliability and very low resistance values. The Model CFN series is optimised for current sensing for power supply, stepper motor drive, and input amplifier applications. The smaller sizes meet the space constrained requirements of mobile device designs, believes Bourns.
The low TCR is determined by characteristics such as the materials used in the resistive element, power rating, and physical size of the component. Bourns has leveraged metal foil technology to achieve lower resistance values, ranging from 5.0 to 40 mOhms, and still provide power ratings of 0.25 to 1.0W in components small enough for mobile applications. The ±50 ppm per degree C attribute with low resistance values helps minimise self-heating so the resistor remains reliable and stays within its one to five per cent tolerance over time, says Bourns.
The Model CFN resistors’ structure and mounting style are also designed to optimise performance. A metal foil resistive element on the bottom of the ceramic substrate shortens the thermal pathway and improves heat dissipation characteristics. The rear mount style helps prevent surface damage during assembly that otherwise could cause a short for reliable, stable operation to meet the demands of the mobile market.
The Bourns Model CFN metal foil current sense resistor series is available now in all variations. The resistors are RoHS-compliant and halogen free.
Bourns manufactures and supplies position and speed sensors, circuit protection solutions, magnetic components, microelectronic modules, panel controls and resistive products. The company is headquartered in Riverside, California, USA and serves a broad range of markets, including automotive, industrial, consumer, communications, medical (low/medium risk) and audio.