Linear Technology announces the LT3590, a 48V, buck mode DC/DC converter designed to operate as a constant-current LED driver.

An internal 55V, 80mA switch and Schottky diode enable it to drive up to ten 50mA LEDs in a single series string from a 48V input, making it ideal for industrial and LED signage applications. Series connection of the LEDs provides identical LED currents up to 50mA, resulting in uniform brightness and eliminating the need of ballast resistors.

Dimming is adjusted via the CTRL pin and ratios as high as 200:1 can be attained. Its switching frequency of 850kHz enables the use of tiny inductors and ceramic capacitors while providing efficiency as high as 91 per cent. Combined with a 2mm x 2mm DFN or SC-70 package, it offers a very compact solution for driving high current LEDs.

The LT3590 utilizes a fixed frequency current mode architecture which offers stable operation over a wide range of input and output voltages. A 200mV feedback voltage offers ±5 per cent accuracy, ensuring consistent LED brightness.

The LT3590 is available from stock in either a 2mm x 2mm DFN-6 or 8-lead SC-70 package. 1,000-piece pricing starts at $1.40 each for both versions.

Summary of Features: LT3590 

• 4.5V to 55V Input Voltage Range 
   
• Up to 50mA LED Current 
   
• 80mA, 55V Switch 
   
• Internal Schottky Diode
  
• 15uA Supply Current in Shutdown 
   
• 500uA Supply Current Operating, Not Switching
  
• Switching Frequency: 850kHz 
   
• 200mV Feedback Voltage with ±5 per cent Accuracy 
   
• CTRL Input Performs Dimming and Shutdown 
   
• 91 per cent Efficiency (10 LEDs, 50mA)
  
• Requires Only 1uF Output Capacitor
  
• 8-Lead SC70 Package
  
• 6-Lead 2mm × 2mm DFN Package

Contact information

Alastair Boyd, Area Sales Manager UK, Ireland, South Africa and Israel, Linear Technology (UK) Limited.
3 The Listons, Liston Road, Marlow, Buckinghamshire SL7 1FD
Tel: +44 (0)1628 477066  Fax: +44 (0)1628 478153  www.linear.com Email: aboyd@linear.com