Features

• Wide (1000:1) PWM Dimming Range with No ColorShift
• Independent Dimming and Shutdown Control of the LED 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 2.5MHz
• 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

Typical Application

Description

The LT3486 is a dual step-up DC/DC converter specifically 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 independent 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 2.5MHz range. A low 200mV feedback voltage (±3% accuracy) minimizes power loss in the current setting resistor for better efficiency. 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.