MIC2298-15YML-TR

MIC2298 3.5A Minimum, 1MHz Boost High Brightness White LED Driver General Description Features The MIC2298 is a high power boost-switching regulator 3.5A minimum switch current delivers at least 7W of that is optimized for constant-current control. The MIC2298 output power over-temperature is capable of driving up to 2 series 1A white LED for 200mV 10% feedback voltage photoflash, flashlight and other applications. The feedback 2.5V to 10V input voltage voltage is only 200mV, minimizing ballast power dissipa- Output voltage up to 30V (max) tion in constant-current control applications for improved operating efficiency. 12-pin 3mm x 3mm leadless MLF package The MIC2298 has a brightness pin that allows for a Available output over-voltage protection (OVP) programmable torch mode as well full flash with a single 1MHz operation pin when driving high current LEDs. Programmable output current The MIC2298 implements a constant frequency 1MHz <1% line regulation PWM control scheme to make the smallest possible 1A shutdown current design. Over temperature protection The 2.5V to 10V input voltage range of MIC2298 allows Externally programmable soft-start direct operation from 1- and 2-cell Li Ion as well as 3- to 6- cell NiCad/NiMH/Alkaline battery sources. Maximum Under-voltage lockout (UVLO) battery life is assured with a low 1A shutdown current. 40 C to +125 C junction temperature range The MIC2298 is available in a low profile 12-pin 3x3 MLF package. Applications Data sheets and support documentation can be found on Cell phones Micrels web site at www.micrel.com. PDAs Digital cameras White LED flashlights Typical Application Figure 1. High Power White LED Driver MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2298 Ordering Information Part Number OVP Frequency Junction Temp. Range Package Lead Finish MIC2298-15YML 15V 1MHz 40 to +125C 12-Pin 3x3 MLF Pb-Free Note: MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration BRT 1 12 COMP SS/DIM 2 11 EN FB 3 10 VIN AGND 4 9 OVP EP PGND 5 8 SW 6 7 PGND SW 12-Pin 3mm x 3mm MLF (ML) (Top View) Pin Description Pin Number Pin Name Pin Function BRT (input): Apply a voltage greater than or equal to 1V to achieve full 1 BRT brightness current as determined by the ballast resistor. A 10A current source sets the voltage on the resistor. Hence a 50K resistor would yield 0.5V which causes a reduction in LED current to 50% of full brightness. Grounding the BRT reduces the current further to 20% of full brightness. This pin may also be driven by a PWM signal for the same effect. 2 SS/DIM Soft start/dimming (input) 40k source. Connect a capacitor to GND for soft- start. Clamp the pin to a known voltage to control the internal reference voltage and hence the output current. This can also be done with a resistor to GND 3 FB Feedback (Input): Output voltage sense node. Connect the cathode of the LED to this pin. 4 AGND Analog Ground 5,6 PGND Power Ground 7,8 SW Switch Node: Internal power BIPOLAR collector. 9 OVP Over-Voltage Protection (OVP): Connect to the output voltage to clamp the maximum output voltage. A resistor divider from this pin to ground could be used to raise the OVP level beyond 15V (max) 10 VIN Supply (Input): 2.5V to 10V for internal circuitry. 11 EN Enable (Input): Applying 1.5V or greater enables the regulator. Applying a voltage of 0.4V or less disables the MIC2298. 12 COMP Compensation pin (input): Add external R and C to GND to stabilize the converter. Pad EP Ground (Return): Backside exposed pad. M9999-101707-B October 2007 2