MIC3287YD5 TR Microchip

Micrel, Inc MIC3287 MIC3287 1.2MHz PWM White LED Driver with OVP in Thin SOT-23 and 2mm x 2mm MFL General Description Features The MIC3287 is a 1.2MHz pulse width modulated (PWM) 2.8V to 6.5V Input Voltage step-up switching regulator that is optimized for constant cur- 350mA Switch Current rent white LED driving applications. With a switch current of 1.2 MHz PWM Operation over 350mA, the MIC3287-24 drives a string of up to 4 white 250mV Feedback Voltage LEDs in series, ensuring uniform brightness and eliminating Optional 24V Output Over-Voltage Protection (OVP) several ballast resistors. Up to 36V Output Voltage without OVP <1% Line and Load Regulation The MIC3287 implements a constant frequency 1.2MHz PWM <1A Shutdown Current current-mode control scheme. The high frequency PWM op- Over-Temperature Protection eration saves board space by reducing external component Under-Voltage Lock Out (UVLO) sizes. The added benefit of the constant frequency PWM Low Profile Thin SOT-23-5 Package Option control scheme as opposed to variable frequency control Low Profile Thin SOT-23-6 Package Option schemes is much lower noise and input ripple injected back 8-pin 2mm x 2mm MLF Package Option to the battery source. To optimize efficiency, the feedback 40C to +125C Junction Temperature Range voltage is set to only 250mV. The MIC3287 is also available with a maximum 24V over-voltage protection. The MIC3287 is available in low profile Thin SOT-23 5-pin Applications and Thin SOT-23 6-pin packages. The MIC3287 has a junc- White LED Driver for Backlighting: tion temperature range of 40C to +125C. - Cell phones All support documentation can be found on Micrels web site - PDAs at: www.micrel.com. - GPS systems - Digital cameras - MP3 players - IP phones LED Flashlights Constant Current Power Supplies Typical Application 10H 10H MIC3287YD5 MIC3287-24YD6 5 1 6 1 VIN SW VIN SW 1-Cell 1F 1-Cell 1F 4 5 EN OVP Li Ion 0.22F 0.22F 4 3 Li Ion FB EN 3 250mV FB 250mV GND GND 2 2 4-Series White LED Driver 3-Series White LED Driver in Thin SOT-23-5 with Output OVP in Thin SOT-23-6 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. MIC3287 Ordering Information Marking Overvoltage Junction Part Number Code Protection Temp. Range Package Lead Finish MIC3287YD5 WGAA N/A -40C to +125C Thin SOT-23-5 Lead Free MIC3287-24YD6 WHAA 24V -40C to +125C Thin SOT-23-6 Lead Free MIC3287-24YML WLA 24V -40C to +125C 8-Pin 2mm x 2mm MLF Lead Free Pin Configuration FB GND SW FB GND SW 3 2 1 3 2 1 VIN 1 8 PGND OVP 2 7 SW EN 3 6 FB 4 5 4 5 6 AGND 4 5 NC EN VIN EN OVP VIN EP TSOT-23-5 (YD5) TSOT-23-6 (YD6) 8-Pin 2mm x 2mm MLF (YML) Pin Description Pin Number Pin Number Pin Number TSOT-23-5 TSOT-23-6 8-Pin MLF Pin Name Pin Function 1 1 7 SW Switch Node (Input): Internal power bipolar collector. 2 2 4 AGND Analog Ground (Return): Ground. 2 2 8 PGND Power Ground (Return): Ground. 3 3 6 FB Feedback (Input): Output voltage sense node. Connect the cathode of the LED to this pin. A resistor from this pin to ground sets the LED current. 4 4 3 EN Enable (Input): Logic high enables regulator. Logic low shuts down regu- lator. 5 6 1 VIN Supply (Input): 2.8V to 6.5V for internal circuitry. 5 2 OVP Overvoltage Protection (Input): Connect to the output. 5 NC Not Connected EP EP Exposed Backside Pad: Connect to ground. April 2010 2 M9999-042910