Connection Diagram

14 Pin Dual LLP Package

20151202

NS Package Number SDA14B

Pin Descriptions

Pin

Name

Function

9V

IN

Input Voltage. Input range: 2.7V to 5.5V.

13

T/F

TORCH/FLASH Pin. Low = Torch Mode, High = Flash Mode

8

SW

Switch Pin

10

OVP

Over Voltage Protection Pin

3V

C

Compensation network connection. Connected to the output of the voltage error amplifier.

5

SD(LM3551)

EN(LM3552)

Shutdown pin logic input. High = Shutdown, Low = Enabled

Enable pin logic input. High = Enabled, Low = Shutdown

12

FTO

Flash Timeout. External capacitor determines max. duration allowed flash pulse

11

SS

Soft Start Pin

4

FB

Feedback Pin

14

FET-T

Torch FET Drain

2

FET-F

Flash FET Drain

1,7,DAP

GND

Ground

6

AGND

Analog Ground. Connect the ground of the compensation components, C

cap to AGND. AGND must be connected to the GND pin through a low impedance

connection.

Ordering Information

Order Number

SD / EN

Package Marking

Supplied As

LM3551SD

SD

L3551SD

250 units, Tape-and-Reel

LM3551SDX

SD

L3551SD

3000 units, Tape-and-Reel

LM3552SD

EN

L3552SD

250 units, Tape-and-Reel

LM3552SDX

EN

L3552SD

3000 units, Tape-and-Reel

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