The CAT4002B, CAT4003B and CAT4004B provide respectively two, three and four matched low dropout current sources to drive LEDs. The CAT400XB requires no external RSET resistor; the LED current is internally set to 25 mA when the device is first enabled. Each LED channel includes an individual control loop allowing the device to handle a wide range of LED forward voltages while still maintaining tight current matching. The EN/DIM logic input supports the device enable and a digital dimming interface for setting the LED channel current with 32 linear dimming levels.