Linear Technology announces hjigh-side current-sense LED driver

Date Announced: 13 Apr 2010 Linear Technology announces the H-grade version of the LT3517. The LT3517 is a high side current sense DC/DC converter designed to drive high current LEDs at constant current. Its 3V to 30V input voltage range with transient protection to 40V makes it ideal for a range of applications, including automotive, industrial and architectural lighting. The H-grade version operates with a junction temperature up to 150ºC, compared to the E- and I-grade versions' 125ºC maximum junction temperature. All electrical specifications are identical for the E-, I- and H-grade versions. The H-grade parts are tested and guaranteed to the maximum junction temperature of 150ºC, making them ideal for automotive and industrial applications which are subjected to high ambient temperatures.The LT3517 can drive up to four 300mA white LEDs from a nominal 12V input, making it ideal for applications such as automotive display backlighting. The LT3517 senses output current at the high side of the LED, enabling buck, buck-boost or boost configurations. The device delivers efficiencies up to 90% in boost mode from a 4mm x 4mm QFN package. The LT3517 offers True Color PWM™ dimming which ensures constant LED color with dimming ranges of up to 5,000:1. For less demanding dimming requirements, the CTRL pin can be used to provide 10:1 analog dimming. Its fixed frequency, current mode architecture offers stable operation over a wide range of supply and output voltages. A frequency adjust pin enables the user to program the frequency between 250kHz and 2.5MHz to optimize efficiency while minimizing external component size.The LT3517HUF is available from stock in 16-pin QFN package, priced starting at $3.49 each in 1,000-piece quantities. For more information, visit www.linear.com. Summary Features LT3517H150ºC Maximum Junction Temperature5000:1 True Color PWM™ Dimming Ratio1.5A, 45V Internal Switch (LT3517)100mV High Side Current SenseOpen LED ProtectionAdjustable Frequency: 250kHz to 2.5MHzWide Input Voltage Range: • Operation from 3V to 30V • Transient Protection to 40V Operates in Boost, Buck Mode & Buck-Boost ModeGate Driver for PMOS LED DisconnectConstant-Current & Constant-Voltage RegulationCTRL Pin Provides 10:1 Analog DimmingLow Shutdown Current: <1µATiny (4mm × 4mm) 16-Pin QFN PackageAbout Linear TechnologyLinear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, µModule® products, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.

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