LT3486

Features:

Wide (1000:1) PWM Dimming Range with NoColorShift
Independent Dimming and Shutdown Control of theLED Drivers
Drives Up to 16 White LEDs at 25mA (8 per Driver) from a Single Li-Ion Cell
Drives Up to 16 White LEDs at 100mA (8 per Driver) from 12V Supply
±3% LED Current Programming Accuracy
Open LED Protection: 36V Clamp Voltage
Fixed Frequency Operation: Up to 2MHz
Wide Input Voltage Range: 2.5V to 24V
Low Shutdown Current: ICC < 1µA
Overtemperature Protection
Available in (5mm * 3mm * 0.75mm) 16-Pin DFN and 16-Pin Thermally Enhanced TSSOP Packages


Application

Notebook PC Display
LED Camera Light for Cell Phones
Car Dashboard Lighting
Avionics Displays


Pinout




Specifications

Input Voltage (VIN) ...................................................25V
⎯S⎯H⎯D⎯N Voltage ..........................................................25V
SW1, SW2 Voltages .................................................40V
OVP1, OVP2 Voltages ...............................................40V
CTRL1, CTRL2 Voltages ...........................................10V
PWM1, PWM2 Voltages ...........................................10V
FB1, FB2 Voltages .....................................................10V
Operating Temperature Range (Note 2) ...40°C to 85°C
Storage Temperature Range
DFN ...................................................65°C to 125°C
TSSOP ............................................... 65°C to 150°C
Maximum Junction Temperature .......................... 125°C
Lead Temperature (Soldering, 10sec, TSSOP) ...... 300°C

Description

The LT®3486 is a dual step-up DC/DC converter specifi cally designed to drive up to 16 White LEDs (8 in series per converter) at constant current from a single Li-Ion cell. Series connection of the LEDs provides identical
LED currents resulting in uniform brightness. The two ndependent converters are capable of driving asymmetric
LED strings.

The dimming of the two LED strings can be controlled independently via the respective CTRL pins. An internal
dimming system allows the dimming range to be extended up to 1000:1 by feeding a PWM signal to the respective PWM pins. The LT3486 operating frequency can be set with an external resistor over a 200kHz to 2MHz range. A low 200mV feedback voltage (±3% accuracy) minimizes power loss in the current setting resistor for better effi ciency. Additional features include output voltage limiting when LEDs are disconnected and overtemperature protection.

The LT3486 is available in a space saving 16-pin DFN (5mm × 3mm × 0.75mm) and 16-pin thermally enhanced
TSSOP packages.