LT3952’s 3V to 42V input voltage range suits it for a wide variety of applications, including automotive, industrial and architectural lighting. It can drive up to sixteen 350 mA white LEDs from a nominal 12V input, delivering in excess of 15W. It incorporates a high side current sense, enabling its use in boost mode, buck mode, buck-boost mode or SEPIC topologies. Internal spread-spectrum frequency modulation minimises EMI concerns.
The LT3952 delivers efficiencies of over 94% in the boost topology, eliminating the need for external heat sinking, and internal LED short-circuit protection enables added reliability. A frequency adjust pin permits the user to program the switching frequency between 200 kHz and 3 MHz. The device delivers over 90% efficiency while switching at 2 MHz in a tiny solution footprint. The LT3952 provides a very compact high power LED driver solution in a thermally enhanced TSSOP-28E package.
The chip has a gate driver for a PMOS LED disconnect switch, delivering dimming ratios of up to 4,000:1 using an external PWM signal. For less demanding dimming requirements, the CTRL pin can be used to offer a 10:1 analogue dimming range and an internal PWM generator can be used for 5:1 dimming. The LT3952’s fixed frequency, current-mode architecture offers stable operation over a wide range of supply and output voltages. Output short-circuit protection and open LED protection enhance system reliability. Other features include frequency synchronisation, spread-spectrum frequency modulation, programmable VIN undervoltage and overvoltage protection, and an input current limit and monitor.
The LT3952EFE is available in a thermally enhanced 28-lead TSSOP package. Three temperature grades are available, with operation from -40°C to 125°C (junction) for the extended, and industrial grades, and a high temperature grade of -40°C to 150°C. Pricing starts at $3.95 (1000).
Linear Technology; www.linear.com/product/LT3952