LT3599
4-Channel 120mA LED Driver
with 1ꢀ5ꢁ Cꢂrrent ꢃatꢄhinꢅ
FEATURES
DESCRIPTION
True Color PWMTM Dimming Ratio Up to 3000:1
The LT®3599 is a fixed frequency 2A step-up DC/DC
converter designed to drive four strings of 120mA LEDs
up to a 44V output voltage. The switching frequency
is programmable from 200kHz to 2.1MHz through an
external resistor.
n
n
Drives Four Strings of LEDs at Up to 120mA
n
1ꢀ.% Accurate LED Current Matcꢁing
n
Wide Input Voltage Range: 3.1V to 30V
n
Output Voltage Up to 44V
n
Regulates LED Current Even When V > V
IN
OUT
LED dimming can be achieved with analog dimming on
the CTRL pin, and with pulse width modulation dimming
on the PWM pin. The LT3599 accurately regulates LED
current even when the input voltage is higher than the
LED output voltage.
n
n
n
n
n
n
n
n
n
Disconnects LEDs in Shutdown
Programmable Maximum V
(Regulated)
OUT
Open/Short LED Protection and Fault Flags
Programmable LED Current Derating
Adjustable Frequency: 200kHz to 2.1MHz
Synchronizable to an External Clock
Analog Dimming Up to 20:1
Programmable Input UVLO with Hysteresis
Thermally Enhanced 32-Pin (5mm × 5mm) QFN and
28-Pin TSSOP Packages
Additional features include programmable LED current
derating, switching frequency synchronization to an ex-
ternal clock, LED string disable control, OPENLED alert
pin, SHORTLED alert pins and programmable maximum
output voltage when all LED strings are disconnected.
The LT3599 is available in the thermally enhanced 32-pin
(5mm × 5mm) QFN and 28-pin TSSOP packages.
APPLICATIONS
n
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are
the property of their respective owners. Protected by U.S. Patents, including 7199560.
Automotive Navigation TFT LCD Displays
Desktop and Notebook TFT LCD Displays
n
TYPICAL APPLICATION
90% Efficient 12W LED Driver
PV
IN
8V TO 24V
10μH
4.7μF
s2
V
IN
3.3μF
220pF
3.1V TO 5.5V
LED Current Matcꢁing
V
IN
V
SW
V
OUT
IN
V
IN
1μF
1.5
V
O_SW
100k
ALL FOUR LED STRINGS
1M
100k
SHORTLED
OPENLED
200k
1.0
0.5
FB
SHDN/UVLO
PWM
31.6k
PWM
31.6k
33.2k
SYNC
LT3599
CTRL
RT
0
V
REF
53.6k
–0.5
–1.0
–1.5
52.3k
T
SET
LED1
LED2
LED3
LED4
80.6k
DISABLE4
I
–50
0
25
50
75
125
–25
100
80mA PER STRING
V
TEMPERATURE (°C)
SS
GND
47nF
SET
C
3599 TA01b
16.5k
100pF
2k
10nF
3599 TA01a
3599f
1