CAT4237

www.DataSheet4U.com CAT4237 High Voltage CMOS Boost White LED Driver Features Drives 6 to 8 White LEDs in series from 3V Up to 87% Efficiency Low Quiescent Ground Current 0.6mA Adjustable Output Current (up to 40mA) High Frequency 1MHz Operation High Voltage Power Switch Shutdown current less than 1µA Open LED low power mode Automatic Shutdown at 1.9V (UVLO) Thermal shutdown protection Thin SOT23 5-Lead (1mm max height) Product Description The CAT4237 is a DC/DC step-up converter that delivers an accurate constant current ideal for driving LEDs. Operation at a constant switching frequency of 1MHz allows the device to be used with small value external ceramic capacitors and inductor. LEDs connected in series are driven with a regulated current set by the external resistor R1. LED currents up to 40mA can be supported over a wide range of input supply voltages from 2.8V to 5.5V, making the device ideal for battery-powered applications. The CAT4237 high-voltage output stage is perfect for driving six, seven or eight white LEDs in series with inherent current matching in LCD backlight applications. LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power-down mode with “zero” quiescent current. In addition to thermal protection and overload current limiting, the device also enters a very low power operating mode during “Open LED” fault conditions....