LT3517 Full-Featured LED Driver with 1.5A Switch Current FEATURES DESCRIPTION
The LT®3517 is a current mode DC/DC converter with an internal 1.5A, 45V switch specifically designed to drive LEDs. The LT3517 operates as a LED driver in boost, buck mode and buck-boost mode. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. Programmable switching frequency allows optimization of the external components for efficiency or component size. The switching frequency of LT3517 can be synchronized to an external clock signal. The LED current is externally programmable with a 100mV sense resistor. The external PWM input provides up to 5000:1 LED dimming. The CTRL pin provides further 10:1 dimming ratio. The LT3517 is available in the tiny footprint 16-lead QFN (4mm Ч 4mm) and the 16-pin TSSOP packages. The LT3517 provides a complete solution for both constantvoltage and constant-current applications.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and 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, 7321203, 7746300. 5000:1 True Color PWMTM Dimming Ratio 1.5A, 45V Internal Switch 100mV High Side Current Sense Open LED Protection Adjustable Frequency: 250kHz to 2.5MHz Wide Input Voltage Range: Operation from 3V to 30V Transient Protection to 40V Operates in Boost, Buck Mode and Buck-Boost Mode Gate Driver for PMOS LED Disconnect Constant-Current and Constant-Voltage Regulation CTRL Pin Provides 10:1 Analog Dimming Low Shutdown Current: <1µA Available in (4mm Ч 4mm) 16-Lead QFN and 16-Pin TSSOP Packages APPLICATIONS Display Backlighting Automotive and Avionic Lighting Illumination Scanners TYPICAL APPLICATION
1A Buck Mode LED Driver
100 PVIN 24V 100m 2.2µF ISP VIN SHDN LT3517 CTRL PWM FB SS 50 40 16.9k 1MHz 0.1µF
3517 TA01a Efficiency
10µF 90 EFFICIENCY (%) CTRL = VREF 1A ISN TG SW 15µH 80 70 60 VIN 3.3V 2.2µF VREF PWM SYNC RT TGEN VREF VC GND 0.1µF 0 20 40 60 80 PWM DUTY CYCLE (%) 100
3517 TA01b 3517fg For more information www.linear.com/LT3517 1 LT3517 ABSOLUTE MAXIMUM RATINGS
(Note 1) VIN, SHDN, PWM, TGEN (Note 3).40V SW, ISP ISN, TG .45V , TG Pin Below ISP Pin .10V FB, SYNC, SS, CTRL .6V VC, RT, VREF .3V Operating Junction Temperature Range (Notes 2,4) LT3517E .40°C to 125°C LT3517I .40°C to 125°C LT3517H .40°C to 150°C Storage Temperature Range QFN.65°C to 150°C TSSOP .65°C to 150°C Lead Temperature (Soldering …
