LT3593
1MHz White LED Driver with
Output Disconnect and One
Pin Current Programming
FEATURES
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DESCRIPTION
The LT
®
3593 is a step-up DC/DC converter designed to
drive up to ten white LEDs in series from a Li-Ion cell.
Series connection of the LEDs provides identical LED
currents and eliminates the need for ballast resistors. The
device features a unique high side LED current sense that
enables the part to function as a “one wire current source”
where the low side of the LED string can be returned to
ground anywhere.
Additional features include output disconnect in shutdown,
open LED protection and 1-pin shutdown/LED current
control. The CTRL pin is toggled to adjust the LED current
via an internal counter and a 5-bit DAC.
The LT3593 switches at 1MHz, allowing the use of tiny
external components. Constant frequency switching re-
sults in low input noise and a small output capacitor. The
LT3593 is available in the 6-lead DFN (2mm
×
2mm) as
well as the 6-lead SOT-23 packages.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Drives Up to Ten White LEDs from a 3V Supply
One Pin Shutdown and Current Programming
LEDs Disconnected in Shutdown
32:1 Linear Brightness Control Range
V
IN
Range: 2.7V to 5.5V
±5% Output Current Accuracy at Full Scale
Low Shutdown Current: 3μA
1MHz Switching Frequency
Requires Only 1μF Output Capacitor
Low Profile 6-Lead DFN (2mm
×
2mm
×
0.75mm)
and 6-Lead SOT-23 Packages
APPLICATIONS
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Cell Phones
Digital Cameras
PDAs, Handheld Computers
MP3 Players
GPS Receivers
TYPICAL APPLICATION
Li-Ion Driver for Ten White LEDs
V
IN
3V TO 5V
10μH
1μF
V
IN
SW
CAP
LT3593
SHUTDOWN AND
CURRENT CONTROL
CTRL
GND
LED
1μF
EFFI CIENCY (%)
90
80
70
60
50
40
30
Conversion Efficiency
V
IN
= 3.6V
10 LEDs
0
5
10
15
LED CURRENT (mA)
20
3593 TA01b
3593 TA01a
3593f
1
LINER [ LINEAR TECHNOLOGY ]
