LT3597
60V Triple Step-Down
LED Driver
FEATURES
DESCRIPTION
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Three 100mA Buck Regulators, Each Drives Up to
The LT®3597 is a 60V triple step-down LED driver capable
ofachieving 10,000:1 digitalPWM dimming at 100Hzwith
fast NPN current sources driving up to 10 LEDs in each
channel. LED dimming can also be achieved via analog
control of the CTRL1-3 pin.
10 LEDs with Fast NPN Current Sources
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Fast Current Sources for <1µs Pulse Widths
(10,000:1 True Color PWM™ Dimming at 100Hz)
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LEDs Disconnected in Shutdown
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Adaptive V
for Increased Efficiency
OUT
The step-down switching frequency is programmed be-
tween200kHzand1MHz.Thefrequencyisalsosynchroniz-
able to an external clock. The LT3597 provides maximum
LED brightness while adhering to manufacturers’ speci-
fications for thermal derating. The derate temperature is
programmedbyplacinganegativetemperaturecoefficient
(NTC) resistor on the master control pin.
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6V to 60V Input Voltage Range
2% LED Current Matching
External Resistor Sets LED Current for Each Channel
Internal Compensation and Soft-Start
Programmable Switching Frequency (200kHz to 1MHz)
Synchronizable to External Clock
Open LED Detection and Reporting
The LT3597 adaptively controls V
in order to achieve
Shorted LED Pin Protection and Reporting
Programmable LED Thermal Derating
Programmable Temperature Protection
5mm × 8mm Thermally Enhanced QFN Package
with a 0.6mm High Voltage Pin Spacing
OUT
optimal efficiency. Other features include: 2% LED cur-
rent matching between channels, open LED reporting,
shorted LED protection, programmable LED current, and
programmable temperature protection.
L, 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.
APPLICATIONS
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LED Billboards and Signboards
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Mono, Multi, Full-Color LED Displays
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Large Screen Display LED Backlighting
Automotive, Industrial, and Medical Displays
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TYPICAL APPLICATION
Triple Step-Down RGB Single Pixel LED Driver, 100mA Current
V
IN
48V
V
BOOST2
IN
270k
91k
10,000:1 PWM Dimming at 100Hz
10µF
0.1µF
0.1µF
10k
100µH
V
OUT2
EN/UVLO
BOOST1
SW1
SW2
3.3µF 97k
9.1k
DA2
V
100µH
3.3µF
OUT1
0.1µF
G
FB2
97k
PWM
2V/DIV
DA1
V
OUT2
LED2
BOOST3
R
9.1k
FB1
LT3597
100µH
V
OUT3
V
SW3
DA3
FB3
OUT1
I
LED
50mA/DIV
LED1
BIAS
3.3µF 97k
9.1k
V
CC
5V
10µF
B
100k
3597 TA01b
200ns/DIV
FAULT
PWM1-3
CTRL1-3
SYNC
3
V
OUT3
LED3
3
V
V
REF
REF
82.5k
RT
T
SET
33.2k
CTRLM
I
I
I
GND
SET1
SET2
SET3
49.9k
3597 TA01a
100k
(1MHz)
20k
20k
20k
3597f
1