36V 2.2MHz Buck LED Driver from Linear Technology

21st November 2008

ES Admin

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Datasheet

Linear Technology has announced the LT3592, a 36V step-down DC/DC converter designed to operate as a constant current LED driver. Its internal 36V, 900mA switch enables it to drive up to six 500mA white LED in a single string from a 36V input for industrial and LED signage applications. It can also drive two 500mA LEDs from a 12V lead acid battery input for automotive applications.

Series connection of the LEDs provides identical LED currents, resulting in uniform brightness and eliminating the need for ballast resistors. The LT3592’s switching frequency can be adjusted from 400kHz to 2.2MHz via a single resistor. This enables designers to set the switching frequency above critical frequency bands such as AM radio while minimizing external component size. Offered in a 2mm x 3mm DFN-10 or MSOP-10 package, the LT3592 provides a very compact 500mA LED driving solution.

LED current levels of either 10% or 100% of the programmed value are selectable by driving the LT3592’s BRIGHT pin. The LT3592 utilizes a fixed frequency, high side sense, current mode architecture which provides fast transient response and cycle-by-cycle current limiting. Other features include: shorted and open LED protection, single wire LED capability and thermal shutdown.