REF OUT R3 REF OUT R3 T R2 Q1 R2 Q1 R5 VSET SFAULT R5 VSET SFAULT UC C1 C1 GND FB GND FB R6 R1 R6 R1 OD R4 R4 R PFigure 1WENPin DescriptionsPin NumberPin NameFunction 1 VCC Supply input Internal reference voltage. The maximum recommended output current is 50µA and the maximum recommended capacitor 2 REF connected from REF pin to GND is less than 100pF. A potential divider from REF to VSET can be used to accurately set the output LED current. LED current setting threshold. 3 VSET The voltage on VSET sets the reference voltage for the FB pin. This pin is pulled down internally if left floating. The capacitance if needed between VSET and GND is recommended to be less than 1nF. 4 GND Ground Feedback input. When control loop is operating in linear mode, the FB pin will be regulated to the level set by VSET. This 5 FB pin is pulled up internally if left floating. A capacitor may be added between FB and GND to improve noise rejection. Value needs to be limited to 100pF or less. VCC enable level setting for LED-open protection activation. Used in conjunction with VCC to determine 6 SFAULT 1. If LED-open is activated and 2. At what VCC voltage it becomes active This function prevents false triggering on power up. Driving output 7 OUT For 15mA drive current, VCC must be at least 3V greater than VOUT Input for LED-open detection. When LED-open detection function is active, if VFAULT is brought lower than approximately 2.5V, the 8 VFAULT device output will be turned off and will auto-retry driving the output to see if the fault still exists. A PWM dimming function will be realized by adding an open collector/drain signal on this pin. Exposed Pad (Bottom). EP EP Recommended to be connected to a large-area contiguous copper GND plane for effective thermal dissipation. Do not use as the IC’s only electrical GND connection.