1

4

3

2

10

7

8

9

NC

GATE

NC

COFF

NC

NC

5

6

FILTER

GND

3

2

1

6

7

8

VCC

NC

NC

GND

COFF

FILTER

4

5

GATE

LM3444

SNVS682B – NOVEMBER 2010 – REVISED NOVEMBER 2011

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.

Figure 2. 8-Lead SOIC (Top View)

Figure 1. 10-Pin VSSOP (Top View)

See D Package

See DGS Package

PIN DESCRIPTIONS

VSSOP

SOIC

Name

Description

1

1

NC

No internal connection. Leave this pin open.

2

NC

No internal connection. Leave this pin open.

3

NC

No internal connection. Leave this pin open.

4

8

COFF

OFF time setting pin. A user set current and capacitor connected from the output to this pin sets the

constant OFF time of the switching controller.

5

2

FILTER

Filter input. A low pass filter tied to this pin can filter a PWM dimming signal to supply a DC voltage to

control the LED current. Can also be used as an analog dimming input. If not used for dimming connect a

0.1µF capacitor from this pin to ground.

6

3

GND

Circuit ground connection.

7

4

ISNS

LED current sense pin. Connect a resistor from main switching MOSFET source, ISNS to GND to set the

maximum LED current.

8

5

GATE

Power MOSFET driver pin. This output provides the gate drive for the power switching MOSFET of the

buck controller.

9

6

Input voltage pin. This pin provides the power for the internal control circuitry and gate driver.

10

7

NC

No internal connection. Leave this pin open.

ABSOLUTE MAXIMUM RATINGS

(1)

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

availability and specifications.

VALUE / UNITS

–0.3V to +14V

ISNS to GND

–0.3V to +2.5V

FILTER and COFF to GND

–-0.3V to +7.0V

COFF Input Current

60mA

Internally Limited

150°C

Storage Temperature Range

–65°C to +150°C

Maximum Lead Temperature Range (Soldering)

260°C

(1)

Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the

device is intended to be functional, but device parameter specifications may not be guaranteed. For specifications and test conditions,

see the Electrical Characteristics. All voltages are with respect to the potential at the GND pin, unless otherwise specified.

(2)

(3)

Human Body Model, applicable std. JESD22-A114-C.

2

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