Preliminary
RT9300A/B
Tiny Package, Low Dropout Current Source
General Description
The RT9300A/B low-dropout bias supply for white LEDs
is a high-performance alternative to the simple ballast
resistors used in conventional white LED designs. The
RT9300A/B uses a internal resistor to set the bias
current for four LEDs, which are matched to 3%. The
RT9300A/B's advantages over ballast resistors include
much lower bias variation with supply voltage variation,
significantly lower dropout voltage, and in some applications,
significantly improved efficiency. The RT9300A/B requires
a 60/45mV dropout at a 20/15mA load on each output to
match the LED brightness.
Features
Low 60/45mV Dropout at 20/15mA
3% LED Current Matching
Simple LED Brightness Control
2.5V to 5.5V Supply Voltage Range
Thermal Shutdown Protection
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Next-Generation Wireless Handsets
PDAs, Palmtops, and Handy Terminals
Digital Cameras, Camcorders
Battery-Powered Equipment
Ordering Information
RT9300A/B
Package Type
E : SOT-23-6
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Sink Current
A : 20mA
B : 15mA
Pin Configurations
(TOP VIEW)
LED1 LED2 LED3
6
1
EN
5
2
4
3
GND LED4
Note :
RichTek Pb-free and Green products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
100%matte tin (Sn) plating.
SOT-23-6
Note
: There is no pin1 indicator on top mark for SOT-23-6
type, and pin 1 will be lower left pin when reading top mark
from left to right.
Typical Application Circuit
V
IN
C
0.1uF
6
LED1
PWM
1
EN
5
LED2
4
LED3
3
LED4
RT9300A/B
GND
2
Figure 1. Application circuit for backlight.
DS9300A/B-02 March 2007
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
