A Product Line of
Diodes Incorporated
ZXLD381
SINGLE OR MULTI CELL LED DRIVER SOLUTION
Summary
The ZXLD381 is a single cell LED driver designed for applications where step-up voltage conversion from a very low input
voltage is required. These applications mainly operate from 1.5V or 1.2V cells. The IC generates constant current pulses that
are ideal for driving single or multiple LEDs over a wide range of operating voltages.
The ZXLD381 uses a PFM control technique to drive an internal switching transistor which a low saturation resistance. This
ensures high efficiency, even for input voltages as low as 1V.
The IC can start up under full load and operates down to an input voltage of only 0.9V.
The ZXLD381 is offered in the space saving SOT23 package or in die form, offering an excellent cost vs performance solution
for single cell LED driving applications.
Features Pin Assignments
85% Efficiency
SOT23-3
User adjustable output current
Single cell operation (0.9V minimum)
Low saturation voltage switching transistor
SOT23-3 package
Available also in Die form
Simple Application circuit
(Top View)
Application
LED flashlights and torches
LED backlights
White LED driver
Typical Application Circuit
V
IN
L1
V
CC
LED
V
OUT
GND
ZXLD381
1 of 9 May 2010
ZXLD381
Diodes Incorporated
www.diodes.com
Document number: DS32188 Rev. 3 - 2
A Product Line of
Diodes Incorporated
ZXLD381
Block Diagram
VCC
L1
ZXLD381
VOUT
Pulse
Control
LED
1.5V
Con Cof f Rsense
GND
Fig 1. ZXLD381 Block Diagram
Pin Description
Pin No. Name Description
1 GND Ground
2 Switch output external inductor/LED
V
OUT
3 Supply voltage, generally Alkaline, NiMH or NiCd single cell
V
CC
2 of 9 May 2010
ZXLD381
Diodes Incorporated
www.diodes.com
Document number: DS32188 Rev. 3 - 2