MIC3287_10 Datasheet, PDF (1/9 Pages) Micrel Semiconductor – 1.2MHz PWM White LED Driver with OVP in Thin SOT-23 and 2mm x 2mm MFL

Micrel, Inc
MIC3287
MIC3287
1.2MHz PWM White LED Driver with OVP in
Thin SOT-23 and 2mm x 2mm MFL^®
General Description
The MIC3287 is a 1.2MHz pulse width modulated (PWM)
step-up switching regulator that is optimized for constant cur-
rent white LED driving applications. With a switch current of
over 350mA, the MIC3287-24 drives a string of up to 4 white
LEDs in series, ensuring uniform brightness and eliminating
several ballast resistors.
The MIC3287 implements a constant frequency 1.2MHz PWM
current-mode control scheme. The high frequency PWM op-
eration saves board space by reducing external component
sizes. The added benefit of the constant frequency PWM
control scheme as opposed to variable frequency control
schemes is much lower noise and input ripple injected back
to the battery source. To optimize efficiency, the feedback
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
and Thin SOT-23 6-pin packages. The MIC3287 has a junc-
tion temperature range of –40°C to +125°C.
All support documentation can be found on Micrel’s web site
at: www.micrel.com.
Features
• 2.8V to 6.5V Input Voltage
• 350mA Switch Current
• 1.2 MHz PWM Operation
• 250mV Feedback Voltage
• Optional 24V Output Over-Voltage Protection (OVP)
• Up to 36V Output Voltage without OVP
• <1% Line and Load Regulation
• <1µA Shutdown Current
• Over-Temperature Protection
• Under-Voltage Lock Out (UVLO)
• Low Profile Thin SOT-23-5 Package Option
• Low Profile Thin SOT-23-6 Package Option
• 8-pin 2mm x 2mm MLF^® Package Option
• –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
Typical Application
10µH
1-Cell
Li Ion
MIC3287YD5
5
VIN
1
SW
1µF
4 _EN
FB ³
250mV
GND
2
0.22µF
1-Cell
Li Ion
10µH
MIC3287-24YD6
6 _VIN
SW ¹
1µF _{4 EN OVP 5}
FB ³
GND
250mV
2
0.22µF
3-Series White LED Driver in Thin SOT-23-5
4-Series White LED Driver
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 [phone] • fax + 1 [phone] • http://www.micrel.com
April 2010
1
M9999-042910