1

2

3

6

5

4

BOOST

GND

FB

SW

EN/DIM

1

2

3

6

5

4

LM3405

SNVS429B – OCTOBER 2006 – REVISED MAY 2013

www.ti.com

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

Connection Diagram

Figure 1. 6-Lead SOT

Figure 2. Pin 1 Identification

See Package Number DDC (R-PDSO-G6)

PIN DESCRIPTIONS

Pin(s)

Name

Application Information

Voltage at this pin drives the internal NMOS power switch. A bootstrap capacitor is connected between the

1

BOOST

BOOST and SW pins.

Signal and Power ground pin. Place the LED current-setting resistor as close as possible to this pin for accurate

2

GND

current regulation.

3

FB

Feedback pin. Connect an external resistor from FB to GND to set the LED Current.

Enable control input. Logic high enables operation. Toggling this pin with a periodic logic square wave of

4

EN/DIM

varying duty cycle at different frequencies controls the brightness of LEDs. Do not allow this pin to float or be

5

Input supply voltage. Connect a bypass capacitor locally from this pin to GND.

6

SW

Switch pin. Connect this pin to the inductor, catch diode, and bootstrap capacitor.

ABSOLUTE MAXIMUM RATINGS

(1)

If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors

for availability and specifications.

VALUE / UNIT

–0.5V to 20V

SW Voltage

–0.5V to 20V

Boost Voltage

–0.5V to 26V

Boost to SW Voltage

–0.5V to 6.0V

FB Voltage

–0.5V to 3.0V

EN/DIM Voltage

Junction Temperature

150°C

2kV

Storage Temperature

–65°C to +150°C

Soldering Information Infrared/Convection Reflow (15sec)

220°C

(1)

Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings define the conditions under

which the device is intended to be functional. For specific specifications and test conditions, see the Electrical Characteristics.

(2)

Human body model, 1.5k

Ω in series with 100pF.

2

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