User manual

SNS

GATE

COFF

5 6FILTER GND

LM3444 Device Pin-Out

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6 LM3444 Device Pin-Out

7 Pin Descriptions – 10 Pin VSSOP

Pin # Name Description

1 NC No internal connection.

2 NC No internal connection.

3 NC No internal connection.

4 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 FILTER Filter input. A capacitor tied to this pin filters the error amplifier. Could also be used as an analog dimming

input.

6 GND Circuit ground connection.

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

maximum LED current.

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

controller.

9 V

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

10 NC No internal connection.

8 Bill of Materials

Designator Description Manufacturer Part Number RoHS

U1 Offline LED Driver, PowerWise™ Texas Instruments LM3444 Y

C1 Ceramic, X7R, 250VAC, 10% Murata Electronics DE1E3KX332MA5BA01 Y

North America

C2 Ceramic, Polypropylene, 400VDC, 10% WIMA MKP10-.033/400/5P10 Y

C3 CAP, CERM, 330pF, 630V, +/-5%, C0G/NP0, 1206 TDK C3216C0G2J331J Y

C4 Ceramic, X7R, 250V, X2, 10%, 2220 Murata Electronics GA355DR7GF472KW01L Y

North America

C5 CAP, Film, 0.033µF, 630V, +/-10%, TH EPCOS Inc B32921C3333K Y

C9, C11 CAP, CERM, 1µF, 50V, +/-10%, X7R, 1210 MuRata GRM32RR71H105KA01L Y

C10 CAP, CERM, 0.47µF, 50V, +/-10%, X7R, 0805 MuRata GRM21BR71H474KA88L Y

C12 Aluminium Electrolytic, 680uF, 35V, 20%, Nichicon UHE1V681MHD6 Y

C13 CAP, CERM, 1µF, 35V, +/-10%, X7R, 0805 Taiyo Yuden GMK212B7105KG-T Y

C14 CAP, CERM, 0.1µF, 25V, +/-10%, X7R, 0603 MuRata GRM188R71E104KA01D Y

C15 CAP, TANT, 47uF, 16V, +/-10%, 0.35 ohm, 6032-28 AVX TPSC476K016R0350 Y

SMD

C18 CAP, CERM, 2200pF, 50V, +/-10%, X7R, 0603 MuRata GRM188R71H222KA01D Y

C20 CAP, CERM, 330pF, 50V, +/-5%, C0G/NP0, 0603 MuRata GRM1885C1H331JA01D Y

D1 DIODE TVS 250V 600W UNI 5% SMD Littelfuse P6SMB250A Y

AN-2097 LM3444 - 230VAC, 8W Isolated Flyback LED Driver SNVA462F–November 2010–Revised May 2013

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