Microchip | MIC2289-15YML-TR

The MIC2289-15YML TR is a PWM (pulse width modulated), boost-switching 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 is set to only 95 mV. 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 1.2 MHz PWM control scheme. The high frequency, PWM operation saves board space by reducing external component sizes. The added bene?t of the constant frequency PWM scheme in caparison to variable 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 15 V, 24 V, and 34 V. 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 low profile 6-pin Thin SOT-23 and 8-pin 2 mm × 2 mm MLF ® package options. The MIC2289 has a junction temperature range of –40°C to +125°C.

Key Features:

• 2.5 V to 10 V input voltage.
• Output voltage up to 34 V.
• Internal Schottky diode.
• 15 V, 24 V, 34 V output OVP options.
• 1.2 MHz PWM operation.
• Over 500 mA switch current.
• 95 mV feedback voltage.
• <1% line and load regulation.
• <1 µA shutdown current.
• Overtemperature protection.
• UVLO.
• 2 mm × 2 mm 8-pin MLF ® package.
• –40°C to +125°C junction temperature range.

Applications:

• White LED driver for backlighting.
• Cell phones.
• PDAs.
• GPS systems.
• Digital cameras.
• MP3 players.
• IP phones.
• LED flashlights.
• Constant current power supplies.