MIC2287 Micrel, Inc. MIC2287 1.2MHz PWM White LED Driver with OVP in 2mm 2mm MLF and Thin SOT-23 General Description Features The MIC2287 is a 1.2MHz pulse width modulated (PWM), 2.5V to 10V input voltage boost-switching regulator that is optimized for constant- Output voltage up to 34V current, white LED driver applications. With a maximum Over 500mA switch current output voltage of 34V and a switch current of over 500mA, 1.2 MHz PWM operation the MIC2287 easily drives a string of up to 8 white LEDs in 95mV feedback voltage series, ensuring uniform brightness and eliminating several Output Overvoltage Protection (OVP) ballast resistors. Options for 15V, 24V, and 34V OVP <1% line and load regulation The MIC2287 implements a constant frequency, 1.2MHz <1A shutdown current PWM control scheme. The high frequency PWM operation Over-temperature protection saves board space by reducing external component sizes. UVLO The added benet of the constant frequency PWM scheme Low prole Thin SOT-23-5 package option as opposed to variable frequency topologies is much lower 8-lead 2mm 2mm MLF package option noise and input ripple injected back to the battery source. 40C to +125C junction temperature range To optimize efciency, the feedback voltage is set to only 95mV. This reduces the power dissipation in the current set resistor and allows the lowest total output voltage, hence Applications minimal current draw from the battery. White LED driver for backlighting: The MIC2287 is available with 3 levels of overvoltage protec- - Cell phones tion, 15V, 24V, and 34V. This allows designers to choose the - PDAs smallest possible external components with the appropriate - GPS systems voltage ratings for their applications. - Digital cameras - MP3 players The MIC2287 is available in low prole Thin SOT-23 5-lead and - IP phones an 8-lead 2mm 2mm MLF package options. The MIC2287 Photo ash LED driver has a junction temperature range of 40C to +125C. LED ashlights All support documentation can be found on Micrels web site Constant current power supplies at www.micrel.com. Typical Application CMDSH-3 10H CMDSH-3 10H MIC2287BD5 MIC2287-34BML 5 1 VIN SW VIN SW 1-Cell 1F 1-Cell 1F Li Ion 0.22F EN OVP 4 3 0.22F EN FB Li Ion 95mV FB 95mV GND GND 2 6.3 6.3 3-Series White LED Driver in Thin SOT-23 6-Series White LED Driver with Output OVP in 2mm 2mm MLF-8 MLF and MicroLeadFrame are 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 MIC2287 Micrel, Inc. Ordering Information Marking Overvoltage Junction Part Number Code Protection Temp. Range Package Lead Finish MIC2287BD5 SGAA N/A 40C to 125C Thin SOT-23-5 Standard MIC2287YD5 SGAA N/A 40C to 125C Thin SOT-23-5 Lead Free MIC2287-15BML SLA 15V 40C to 125C 2mm x 2mm MLF Standard MIC2287-15YML SLA 15V 40C to 125C 2mm x 2mm MLF Lead Free MIC2287-24BML SLB 24V 40C to 125C 2mm x 2mm MLF Standard MIC2287-24YML SLB 24V 40C to 125C 2mm x 2mm MLF Lead Free MIC2287-34BML SLC 34V 40C to 125C 2mm x 2mm MLF Standard MIC2287-34YML SLC 34V 40C to 125C 2mm x 2mm MLF Lead Free Pin Conguration FB GND SW 2 1 3 OUT 1 8 GND VIN 2 SW 7 EN 3 6 FB 4 5 EN VIN GND 4 EP 5 NC TSOT-23-5 (BD5) 8-Pin MLF (BML) (Top View) Fused Lead Frame Pin Description Pin Number Pin Number TSOT-23-5 2mm 2mm MLF Pin Name Pin Function 1 7 SW Switch node (Input): Internal power BIPOLAR collector. 2 GND Ground (Return): Ground. 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 3 EN Enable (Input): Logic high enables regulator. Logic low shuts down regula- tor. 5 2 VIN Supply (Input): 2.5V to 10V for internal circuitry. 1 OVP Overvoltage protection (Input): Connect to the output. 4 AGND Analog ground. 8 PGND Power ground. 5 NC No connect (no internal connection to die). EP GND Ground (Return): Exposed backside pad. M9999-070105 2 July 2005