3

Date: Dec 5-06 Rev E

Constant Current LED Driver

© 2006 Sipex Corporation

BLOCK DIAGRAM

After 4s at current higher than 266 mA

Power MOSFET leakage current

Variations per volt Vcc change

= 00 mA settles 50µs later after 3rd pulse

Logic HIGH level should never exceed Vcc voltage

Delay between applying Vcc voltage and operating condition

PIN ASSIGNMENTS

Pin

#

Pin

Name

Pin Function

 - 2

LED

LED Current Sink. Connect LED cathode to this pin. Voltage at this pin

should be above 00 mV to maintain regulation.

3

Vcc

Power Supply Input. Place µF decoupling capacitor next to this pin.

4

EN

Enable/Shutdown pin used to enable/disable driver and reset DAC: Logic

High – enable, Logic Low – disable/reset.

5

CTRL DAC Serial Input pin is used to control LED current. Positive pulse edges

sequentially increase LED current with 33.33mA steps up to 033 mA (3

steps). When this pin is held LOW for longer than 00µs the part enters

Sleep Mode.

6

GND

Ground pin for control and bias blocks.

7 - 8 GNDP Ground pin. LED current flows through this pin to ground.

.

2.

3.

4.

5.

6.

7.

8.

9.

0.

.

Notes (Continued from previous page)