Sasco Holz introduces Linear Technology’s LT3755, a 60 V, high-side current sense DC/DC converter designed to drive high current LEDs.

Its 4.5 V to 40 V input voltage range makes it ideal for a wide variety of applications, including automotive, industrial and architectural lighting. The LT3755 uses an external Nchannel MOSFET and can drive up to 14 1 A white LEDs from a nominal 12 V input, delivering in excess of 50W. It incorporates a high-side current sense, enabling it to be used in boost, buck, buckboost or SEPIC and flyback topologies. The LT3755 can deliver efficiencies of over 94% in boost mode, eliminating any need for external heat sinking. A frequency adjust pin permits the user to program the frequency between 100 kHz and 1MHz, optimizing efficiency while minimizing external component size and cost. Combined with a 3 x 3mm QFN package, the LT3755 offers a very compact 50W LED driver solution.

The LT3755 uses True Color PWM™ dimming, which delivers constant LED color with dimming ranges of up to 3,000:1. For less demanding dimming requirements, the CTRL pin can be used to offer a 10:1 analog dimming range. Its fixed frequency, current mode architecture offers stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, making it possible for the converter to operate as a constant-voltage source.

Two versions of the LT3755 are available – the standard LT3755, which offers an Open LED Status pin, and the LT3755-1, which replaces the Open LED Status pin with a frequency synchronization pin. Both the LT3755EUD and LT3755EUD-1 are available from stock in a 16-pin 3 x 3mm QFN package.

Summary of Features of LT3755/-1

- True Color PWM Dimming: 3,000:1
- Wide Input Voltage Range: 4.5 V to 40V
- Output Voltage: up to 60V
- Constant-Current and Constant-Voltage Regulation
- High Side Current Sense: 100mV
- Drives LEDs in Boost-, Buck-, Buck-Boost Mode
- SEPIC or Flyback Topology
- Programmable Frequency: 100 kHz to 1MHz
- Programmable Undervoltage Lockout with Hysteresis
- Open LED Status Pin (LT3755)
- Frequency Synchronization (LT3755-1)
- PWM Disconnect Switch Driver
- CTRL Pin Provides Analog Dimming
- Low Shutdown Current: <1 μA
- Programmable Softstart
- Thermally Enhanced 16-Lead QFN Package (3 x 3mm)

Samples and prices are available at your local Sasco Holz branch office.