4-Channel Regulated Charge Pump White LED Driver

• Drives individually up to 4 LEDs
• Output current up to 30mA per LED
• Digital control On/Off of each LED
• Compatible with supply voltage of 3V to 5.5V
• Power efficiency up to 93%
• 2 modes of operation 1x and 1.5x
• Automatic short circuit detect/disable
• High-frequency Operation at 1MHz
• Low value ceramic capacitors
• "604" compatible pinout
• Soft start and current limiting
• Thin QFN 16-lead package, 4x4mm, 0.8mm max height

The CAT3604 is a charge pump operating in either 1x (LDO) mode or 1.5x fractional mode regulating current through each of the 4 LED pins. Operation at a fixed high frequency of 1MHz typical allows the use of very small value ceramic capacitors.

The CAT3604 drives white light-emitting diodes (LEDs) connected in parallel and provides tightly matched regulated current to achieve uniformity of brightness in LCD backlighting applications. An external resistor R_SET controls the output current level. LED currents of up to 30mA are supported over a range of input supply voltages from 3V to 5.5V, making the device ideal for battery-powered applications.

LED dimming can be accomplished by several methods including using a DC voltage to set the R_SET pin current, applying a PWM signal on the Control signals, or adding a switched resistor in parallel with R_SET. The Enable input pin allows the device to be placed in power-down mode with "zero" quiescent current.

The CAT3604 features short circuit and overcurrent limiting protection. The device is available in a 16-lead thin QFN package with a max height of 0.8mm.

• Color LCD and keypad Backlighting
• Cellular Phones
• Handheld Devices
• Digital Cameras
• PDAs
• Portable MP3 players