National Semiconductor LM3590 Manuals

The LM3590 series white LED driver is a white LED constant current driver capable of supplying up to 3 white LEDs connected in series with 20mA. This device operates over a wide 6V-12.6V input voltage range. The output can accomodate LEDs with a combined forward voltage of up to 11.5V, from a 12V input supply. The LED drive current is programmed by using an external resistor on the ISET pin. LED brightness can be linearly varied up to the programmed LED current by applying a Pulse Width Modulated (PWM) signal to the EN pin of the device. The LED output current of the LM3590 is tightly controlled over temperature and voltage. LED Current matching is guaranteed due to the series configuration of the LEDs. The series topology also simpli- fies the connection between the White LEDs in the display module and the LM3590 since only one connection is re- quired. The LM3590 typically draws only 50µA when operating in the no-load condition and draws less than 0.1µA when the de- vice is shut down. The LM3590 is available in a small 5-pin SOT23 package.

This document is the design manual of LM3590 evaluation board, which introduces the use method, circuit schematic and component information of the evaluation board.