Features

• Low Noise Charge Pump Provides High Efficiency with Automatic Mode Switching
• Multimode Operation: 1x, 1.5x, 2x
• Individual Full-Scale Current Set Resistors
• Up to 500mA Total Output Current
• Single Wire EN/Brightness Control for MAIN and CAM LEDs (8 Brightness Steps)
• 64:1 Brightness Control Range for MAIN Display
• Four 25mA Low Dropout MAIN LED Outputs
• One 400mA Low Dropout CAM LED Output
• Low Noise Constant Frequency Operation*
• Low Shutdown Current: 3μA
• Internal Soft-Start Limits Inrush Current During Startup and Mode Switching
• Open/Short LED Protection
• No Inductors
• 3mm × 3mm 16-Lead Plastic QFN Package

Typical Application

Description

The LTC®3210 is a low noise charge pump DC/DC converter designed to drive four MAIN LEDs and one high current CAM LED for camera lighting. The LTC3210 requires only four small ceramic capacitors and two current set resistors to form a complete LED power supply and current controller.

Built-in soft-start circuitry prevents excessive inrush current during start-up and mode changes. High switching frequency enables the use of small external capacitors. Independent MAIN and CAM full-scale current settings are programmed by two external resistors. Shutdown mode and current output levels are selected via two logic inputs.

The full-scale current through the LEDs is programmed via external resistors. ENM and ENC are toggled to adjust the LED currents via internal counters and DACs. The part is shut down when both ENM and ENC are low for 150μs (typ).

The charge pump optimizes efficiency based on the voltage across the LED current sources. The part powers up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The LTC3210 is available in a 3mm × 3mm 16-lead QFN package.