293
GENERAL DESCRIPTION
ELM900x is a CMOS IC designed for driving white LEDs by one or two dry cell as a power source. ELM900x
can drive two series white LED by 1.5V-3.0V input voltage. ELM900x uses an external inductor as a voltage
booster. ELM900x consists of an oscillator circuit and a driving transistor. The input DC power is transformed
to a 35kHz constant current pulse, when the external inductor switched on and off in 35kHz. In a standard
application inductor is needed as external parts.
FEATURES
Low cost and simple application circuit
High efficiency
Constant average power control
Low noise 35kHz constant frequency switching
Compact SOT-89 package
APPLICATION
White LED flashlight
Laser pointer
High VF LED driver
LCD backlighting
WHITE LED FLASHLIGHT DRIVER
Pin No. Pin Name
1
VSS
2
VDD
3
LX
PIN CONFIGURATION
( TOP VIEW )
SOT-89
MARKING
: Represents the product IC code
90
: Represents the assembly lot number
0
9 repeated
: Represents the assembly lot number
A
Z repeated ( I,O,X excepted )
Symbol
MARKING
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