Linear – High-current LED driver for automotive and industrial applications (LT3518)

Linear Technology has announced the H-grade version of the LT3518, a 45V, 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 the LT3518 ideal for a wide variety of applications, including automotive, industrial and architectural lighting.

The H-grade version operates with a junction temperature up to 150C, compared to the E- and I-grade versions’ 125C maximum junction temperature. All electrical specifications are identical for the E, I and H. The H-grade parts are tested and ‘guaranteed’ to the maximum junction temperature of 150C. They are ideal for automotive and industrial applications, which are subjected to high ambient temperatures.

The LT3518 can drive up to eight 300mA white LEDs from a nominal 12V input, making it well suited for applications such as automotive display backlighting. The LT3518 senses output current at the high side of the LED, enabling buck, buck-boost or boost configurations. It can deliver efficiencies up to 90% in boost mode from a 4mm x 4mm QFN package.

The LT3518 offers True Colour PWM dimming, delivering constant LED colour with dimming ranges of up to 3,000:1. For less demanding dimming requirements, the CNTRL pin can be used to offer 10:1 analog dimming. Its fixed frequency, current-mode architecture ensures 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 LT3518HUF is available from stock in a 16-pin QFN package, says the company.