MIC2843A Datasheet, PDF (1/13 Pages) Micrel Semiconductor – High Efficiency 6 Channel Linear WLED Driver with DAM™ and Ultra Fast PWM™ Control

MIC2843A
High Efficiency 6 Channel Linear WLED
Driver with DAM™ and Ultra Fast
PWM™ Control
General Description
Features
The MIC2843A is a high efficiency linear White LED
(WLED) driver designed to drive up to six WLEDs, greatly
extending battery life for portable display backlighting
keypad backlighting, and camera flash in mobile devices.
The MIC2843A provides the highest possible efficiency as
this architecture has no switching losses present in
traditional charge pumps or inductive boost circuits. The
MIC2843A provides six linear drivers which maintain
constant current for up to six WLEDs. It features a typical
dropout of 40mV at 20mA. This allows the WLEDs to be
driven directly from the battery eliminating switching
noise/losses present with the use of boost circuitry.
• High Efficiency (no Voltage Boost losses)
• Dynamic Average Matching (DAM™)
• Ultra Fast PWM™ control (200Hz to 500kHz)
• Input voltage range: 3.0V to 5.5V
• Dropout of 40mV at 20mA
• Matching better than ±1.5% (typical)
• Current Accuracy better than ±1.5% (typical)
• Maintains proper regulation regardless of how many
channels are utilized
• Available in a 10-pin 2mm x 2mm Thin MLF^® package
The MIC2843A features Dynamic Average Matching™
(DAM™) which is specifically designed to provide optimum
matching across all WLEDs. The six channels are
matched better than ±1.5% typical, ensuring uniform
display illumination under all conditions. The brightness is
controlled through an Ultra Fast PWM™ interface
operating down to less than 1% duty cycle.
Applications
• Mobile handsets
• LCD Handset backlighting
• Handset keypad backlighting
• Digital cameras
The MIC2843A is available in the 10-pin 2mm x 2mm Thin
MLF^® leadless package with a junction temperature range
of -40°C to +125°C.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Portable media/MP3 players
• Portable navigation devices (GPS)
• Portable applications
____________________________________________________________________________________________________________
Typical Application
U1 MIC2843AYMT
U1 MIC2843AYMT
VIN
C1
Low
RSET
Dropout
Linear
Driver
END
PWM
Control
C1
V_IN
V_IN
R_SET
END
PWM
Control
Low
Dropout
Linear
Driver
LCD Display Backlight with Six WLEDs
High Current Flash Driver
Ultra Fast PWM, DAM and Dynamic Average Matching are trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademark Amkor Technology Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
June 2009
M9999-062909-C