LTC3218EDDB#TRMPBF

LTC3218EDDB#TRMPBF is a low-noise, high-current charge pump DC/DC converter capable of driving high current LEDs at up to 400mA from a 2.9V to 4.5V input. A low external parts count (one flying capacitor, two programming resistors and two bypass capacitors at VIN and CPO) makes the LTC3218 ideally suited for small, battery-powered applications. Built-in soft-start circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. A built-in 2-second timer protects the LED during flash mode. The output current level is programmed by an external resistor. The LED current is regulated using an internal high side 220mohm sense resistor. Automatic mode switching optimizes efficiency by monitoring the voltage across the charge pump and switching modes only when dropout is detected. Applications include LED torch/flash supply for DSCs/cellphones.

• Low noise constant-frequency operation, automatic mode switching
• Multi-mode operation: 1x or 2x boost mode, automatic soft-start
• 2-second flash current timeout for LED protection
• Output disconnect, no inductors, single resistor programming capability
• 220mohm internal high side current sense resistor
• CLK frequency is 1MHz typical at (TA = 25°C)
• Charge pump output clamp voltage is 5.3V typical at (TA = 25°C)
• Input current is 14.4μA typical at ( VEN = 3.6V)
• Operating temperature range from -40°C to 85°C
• 10-lead plastic DFN package

บันทึก

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