The CAT4101 is a constant-current sink driving a string of high-brightness LEDs up to 1 A with very low dropout of 0.5 V at full load. It requires no inductor, provides a low noise operation and minimizes the number of components. The LED current is set by an external resistor connected to the RSET pin. The LED pin is compatible with high voltage up to 25 V, allowing the driving of long strings of LEDs. The device ensures an accurate and regulated current in the LEDs independent of supply and LED forward voltage variation. The PWM/EN input allows the device shutdown and the LED brightness adjustment by using an external pulse width modulation (PWM) signal. The driver features a thermal shutdown protection that becomes active whenever the die temperature exceeds 150C. The device is available in a high-power, 5-lead TO-263 package offering excellent thermal dissipation characteristics.