
LT3597
Three 100mA Buck Regulators, Each Drives Up to
Fast Current Sources for <1μs Pulse Widths
LEDs Disconnected in Shutdown
Adaptive V OUT for Increased Efficiency
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
Shorted LED Pin Protection and Reporting
Programmable LED Thermal Derating
Programmable Temperature Protection
5mm × 8mm Thermally Enhanced QFN Package
LED Billboards and Signboards
Mono, Multi, Full-Color LED Displays
Large Screen Display LED Backlighting
Automotive, Industrial, and Medical Displays
FEATURES
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10 LEDs with Fast NPN Current Sources
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(10,000:1 True Color PWM? Dimming at 100Hz)
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with a 0.6mm High Voltage Pin Spacing
APPLICATIONS
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60V Triple Step-Down
LED Driver
DESCRIPTION
The LT ? 3597 is a 60V triple step-down LED driver capable
of achieving 10,000:1 digital PWM dimming at 100Hz with
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.
The step-down switching frequency is programmed be-
tween 200kHz and 1MHz. The frequency is also synchroniz-
able to an external clock. The LT3597 provides maximum
LED brightness while adhering to manufacturers’ speci-
fications for thermal derating. The derate temperature is
programmed by placing a negative temperature coefficient
(NTC) resistor on the master control pin.
The LT3597 adaptively controls V OUT in order to achieve
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.
TYPICAL APPLICATION
Triple Step-Down RGB Single Pixel LED Driver, 100mA Current
V IN
48V
10μF
270k
V IN
EN/UVLO
BOOST2
SW2
0.1μF 100μH
V OUT2
10,000:1 PWM Dimming at 100Hz
91k
BOOST1
DA2
3.3μF
97k
V OUT1
100μH
0.1μF
SW1
FB2
9.1k
G
R
97k
9.1k
V CC
5V
3.3μF
10μF
3
3
100k
DA1
FB1
V OUT1
LED1
BIAS
FAULT
PWM1-3
CTRL1-3
LT3597
V OUT2
LED2
BOOST3
SW3
DA3
FB3
V OUT3
LED3
0.1μF 100μH
3.3μF
V OUT3
97k
9.1k
B
PWM
2V/DIV
I LED
50mA/DIV
200ns/DIV
3597 TA01b
SYNC
RT
V REF
10k
82.5k
V REF
33.2k
(1MHz)
I SET1
20k
I SET2
20k
I SET3
20k
GND
T SET
CTRLM
3597 TA01a
100k
49.9k
3597fa
1