CAT4004A

Constant Current LED Driver with 32 Dimming Levels and Rset CAT4002A, CAT4004A Description The CAT4002A and CAT4004A provide respectively two and four matched low dropout current sources to drive LEDs. The CAT400XA uses an external resistor RSET to set the current in the LED channels. 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 inputs supports device enable and a digital dimming interface for setting the LED channel current with 32 linear dimming levels. LEDs can be powered directly from a Lithium−ion battery due to the low dropout (50 mV at 20 mA) current sinks. The device is available in the tiny 8−pad UDFN 2 mm x 2 mm package with a max height of 0.55 mm, as well as the 6−lead SC−70. Features 2 and 4 LED Current Sinks with Tight Matching 32 Dimming Levels Low Dropout Driver 50 mV at 20 mA No Switching Noise Shutdown Current less than 1 mA LED Current set by External Resistor Dimming via 1−wire EZDim Interface Thermal Shutdown Protection 6−lead SC−70, and 8−pad UDFN 2 mm x 2 mm Packages These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant Applications LCD Display Backlight Cellular Phones Digital Still Cameras Handheld Devices VIN 2.4 V to 5.5 V CIN 1 mF 20 mA LED1 LED2 LED3 LED4 One wire programming RSET 3.74 kW VIN EN/DIM RSET CAT4004A GND Figure 1. Typical Application Circuit...