LM3405AXMYSLASHNOPB datasheet(13/31 Pages) TI1

Part #	LM3405AXMY/NOPB

Description	1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT and MSOP PowerPAD Packages

PDF	31 Pages

Scroll/Zoom	100%

Manufacturer	TI1 [Texas Instruments]

Direct Link	http://www.ti.com

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13 / 31 page

LM3405A

www.ti.com

SNVS508B – OCTOBER 2007 – REVISED OCTOBER 2008

Figure 21. PWM Dimming of LEDs using the EN/DIM Pin

Figure 22. Startup Response to EN/DIM with IF = 1A

Figure 23. Average LED Current versus Duty Cycle of PWM Dimming Signal at EN/DIM Pin

UNDER-VOLTAGE LOCKOUT

Under-voltage lockout (UVLO) prevents the LM3405A from operating until the input voltage exceeds 2.74V

(typical). The UVLO threshold has approximately 440mV of hysteresis, so the part will operate until VIN drops

below 2.3V (typical). Hysteresis prevents the part from turning off during power up if VIN is non-monotonic.

CURRENT LIMIT

The LM3405A uses cycle-by-cycle current limit to protect the internal power switch. During each switching cycle,

a current limit comparator detects if the power switch current exceeds 2.0A (typical), and turns off the switch until

the next switching cycle begins.

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LM3405AXMY/NOPB Datasheet(PDF) 13 Page - Texas Instruments