MIC4801 
High Efficiency 600mA Single Channel 
Linear WLED Driver with 
Ultra Fast PWM™ Control  
 
 
 
 
Ultra Fast PWM is a trademark of Micrel, Inc.
 
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com  
January 2011  M9999-011811-A 
 
General Description 
The  MIC4801  is  a  high  efficiency  White  LED  (WLED) 
driver  designed  to  drive  a  single  LED  up  to  600mA.  The 
MIC4801 constant current driver is designed to drive high 
power LED’s in various lighting applications. The MIC4801 
provides the highest possible efficiency as this architecture 
has  no  switching  losses  present  in  traditional  charge 
pumps  or  inductive  boost  circuits.  It  features  a  typical 
dropout of  130mV  at  400mA. This  allows the LEDs  to  be 
driven  directly  from  the  voltage  source  eliminating 
switching  noise/losses  present  with  the  use  of  boost 
circuitry. The high accuracy (±1% typical) current regulated 
WLED channel ensures uniform display illumination under 
all conditions. The brightness is controlled through an Ultra 
Fast PWM™ Control interface operating down to less than 
1% duty cycle. 
The MIC4801 is available in an 8-pin SOIC 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. 
Features 
• High Efficiency (no Voltage Boost losses) 
•  Ultra Fast PWM™ control (200Hz to 500kHz) 
•  Input voltage range:  3.0V to 5.5V 
•  Dropout of 130mV at 400mA 
•  Programmable LED current with external resistor 
•  Current accuracy of ±1% typical 
Applications 
•  Bill board displays 
•  Marquee displays  
•  Instrument displays  
•  Architectural lighting
 
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Typical Application 
 
High Current Lighting Schematic