Austin, Tex. Silicon Laboratories Inc. has introduced tiny low-loss, high-accuracy AC current sensors for a wide range of power applications. The Si8500 integrates the functional equivalent of a current transformer circuit into a 4 x 4 x 1-mm QFN package, including the current transformer, blocking diode, burden resistor and output RC filter. This reduces board space by up to 75 percent and enclosure volume requirements by up to 80 percent.
The Si8500 family measures up to 20 amps of current for control and protection in power systems and is suitable for a broad range of applications including AC/DC switching power supplies, isolated DC/DC supplies, motor control and electronic ballasts for lighting.
In addition, the Si8500 family integrates temperature and offset compensation circuitry to achieve measurement accuracy of ±5% with a 2 Vpp full-scale output signal swing. It also offers a “ping-pong” output that enables one Si8510 to replace two current transformer circuits in full-bridge applications. The Si8500 is rated to operate from -40° to +125°C in a standard surface-mount package.
By integrating the current sensor into silicon, the Si8500 architecture is said to provide greater than five times lower series resistance and over two times lower series inductance than traditional discrete implementations. This translates directly into lower power dissipation, higher efficiency, lower noise and reduced power supply complexity for both custom and off-the-shelf supplies.
Pricing: Starts at $1.49 for 1,000 pieces.
Availability: Samples are available.
Product information: Si85xx AC current sensors
Silicon Laboratories Inc. , 1-512-416-8500, www.silabs.com