MIC3289 Datasheet, PDF (1/13 Pages) Micrel Semiconductor – 1.2MHz PWM White LED Driver with Internal Schottky Diode and True 1-Wire Digital Control

MIC3289
1.2MHz PWM White LED Driver with
Internal Schottky Diode and True 1-Wire
Digital Control
PRELIMINARY INFORMATION
General Description
Features
The MIC3289 is a PWM boost-switching regulator that is
optimized for constant-current white LED driver
applications. The MIC3289 features an internal Schottky
diode, allowing an efficient DC/DC solution that requires
only 4 external components.
The MIC3289 allows for a single wire simple digital
interface to control the dimming over 16 steps with a log
scale to give better resolution at the lower currents to
better match the sensitivity of the human eye
• 2.5V to 6.5V input voltage
• Output voltage up to 24V
• 16V & 24V OVP options
• Single wire combines 16 level logarithmic brightness &
shutdown control
• Internal Schottky diode
• 1.2 MHz PWM operation
• Over 500mA switch current
The feedback voltage of the MIC3289 is only 250mV,
allowing high efficiency while retaining excellent accuracy
for the white LED current.
The MIC3289 implements a constant frequency 1.2MHz
PWM control scheme. The high frequency PWM operation
saves board space by reducing external component sizes.
The 1.2MHz PWM scheme also reduces switching noise
and ripple to the input power source.
The 2.5V to 6.5V input voltage range of MIC3289 allows
direct operation from single cell Li Ion as well as 3- to 4-
cell NiCad/ NiMH/Alkaline batteries. Battery life is
preserved with a low 1µA shutdown current.
The MIC3289 is available in a low profile Thin SOT23 6-
lead package and a 2mm × 2mm MLF^®-8L package and
has a junction temperature range of –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• Programmable ±5% current control
• <1% line and load regulation
• <1µA shutdown current
• Over temperature protection
• UVLO
• Thin SOT23-6L package option
• 2mm × 2mm leadless MLF^®-8L package option
• –40^oC to +125^oC junction temperature range
Applications
• White/Blue LED driver for backlighting
- Cell phones
- PDAs
- GPS systems
- Digital cameras
- Multimedia / MP3 players
• LED flashlights
• Constant current power supplies
___________________________________________________________________________________________________________
MicroLead Frame and MLF are registered trademarks of Amkor Technologies.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
March 2007
M9999-030407
[phone]