MIC2289

The MIC2289 is a PWM (pulse width modulated), boostswitching regulator that is optimized for constant-current white LED driver applications. The MIC2289 features an internal Schottky diode and three levels of output overvoltage protection providing a small size and efficient DC/DC solution that requires only four external components.

To optimize efficiency, the feedback voltage of MIC2289 is set to only 95mV. This reduces power dissipation in the current set resistor and allows the lowest total output voltage, hence minimal current draw from the battery.

The MIC2289 implements a constant frequency 1.2MHz PWM control scheme. The high frequency, PWM operation saves board space by reducing external component sizes.The added benefit of the constant frequency PWM scheme in caparison to varible frequency is much lower noise and input ripple injected to the input power source.

The MIC2289 clamps the output voltage in case of open LED conditions, protecting itself and the output capacitor. The MIC2289 is available with three output OVP options of 15V,24V, and 34V. The different OVP options allows the use of the smallest possible output capacitor with the appropriate voltage rating for a given application.

The MIC2289 is available in a 2mm * 2mm 8-pin MLF™package and has a junction temperature range of 40°C to +125°C.

All support documentation can be found on Micrel's web site at www.micrel.com.