W-52
CMOS White LED Driver
Description
The W-52 is a DC/DC step up converter that delivers a regulated
output current. Operation at a constant switching frequency of
1.2 MHz allows the device to be used with very small value external
inductor and ceramic capacitors.
The W-52 is targeted to drive multiple white lightïemitting diodes
(LEDs) connected in series and provides the necessary regulated current
to control the brightness and the color purity. An external resistor RSET
controls the output current level. LED currents of up to 40 mA can be
supported over a wide range of input supply voltages from 2 V to 7 V,
making the device ideal for batteryïpowered applications.
A high voltage output stage allows up to 4 White LEDs to be driven
in series. Series drive provides inherent current matching.
LED dimming can be done by using a DC voltage, a logic signal, or
a pulse width modulation (PWM) signal. The shutdown input pin
allows the device to be placed in powerïdown mode with “near zero”
quiescent current.
In addition to overcurrent limiting protection, the device also
includes detection circuitry to ensure protection against openïcircuit
load fault conditions.
The device is available in a low profile (1 mm max height) 6ïlead
TSOTï23 package.
1
TSOTï23
PIN CONNECTIONS
1
VIN
SW
GND
LED
SHDN
RSET
TSOTï23
1 mm Maximum Height
= 250oC/W (free air)
JA
(Top View)
Features
v Low Quiescent Ground Current (0.5 mA Typical)
v Power Efficiency Over 80%
v Compatible Pinout with LT1932
MARKING DIAGRAMS
v Adjustable Output Current (up to 40 mA)
v High Frequency 1.2 MHz Operation
v Input Voltage Operation down to 2.0 V
v Low Resistance (0.5 ) High Voltage Power Switch
v Drives up to 4 White LEDs in Series
v Shutdown Current Less than 1 A
VFYM
VFꢀ=ꢀW-52TDIꢀïGT3
Y = Production Year (Last Digit)
M = Production Month (1ï9, A, B, C or O, N, D)
v Load Fault Protection Against Openïcircuits
v Low Value External Components
ORDERING INFORMATION
v Low Profile (1 mm) TSOTï23 6ïlead Package
v These Devices are PbïFree, Halogen Free/BFR Free and are RoHS
Compliant
Device
Package
Shipping
TSOTï23
(PbïFree)
3,000/
Tape & Reel
W-52TDIꢀï*T3
(Note 1)
Applications
1.
v Color LCD and Keypad Backlighting
v Cellular Phones
NiPdAu Plated Finish (RoHSïcompliant).
v Handheld Terminals
v Digital Cameras
v PDAs/Games
v Portable MP3 Players
¢ NIDEC COPAL ELECTRONICS CORP.ꢀ
'HFHPEHU,ꢀ20ꢁꢂꢀïꢀRev. ꢂ
1
Publication Order Number:ꢀ
W-52/(