L5100

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

2

www.unisonic.com.tw

QW-R103-024,A

PIN DESCRIPTION

PIN NO.

SOT-25

SOT-363

PIN NAME

SYMBOL

FUNCTION

1

1

Switch

SW

Connect inductor/diode here. Minimize trace area at this pin to

reduce EMI.

2

2/5

Ground

GND

Connect directly to local ground plane.

3

3

Feedback

FB

Reference voltage is 95mV. Connect cathode of lowest LED and

resistor here. Calculate resistor value according to the formula:

4

4

Shutdown

SHDN

Connect to 1.5V or higher to enable device; 0.4V or less to disable

device.

5

6

Input Supply

Input Supply Pin. Must be locally bypassed.

BLOCK DIAGRAM

5

1.25V

3

1

2

4

95mV

FB

Pin 5 (SOT-25)

Pin 6 (SOT-363 )

-

+

A1

-

+

-

+

A2

Rc

Cc

Σ

RAMP

GENERATOR

1.2MHz

TIME CONTROL

R

S

Q

DRIVER

SW

Q1

GND

Pin 2 /5 (SOT-363 )

Pin 2

(SOT-25 )

0.2Ω

SHUTDOWN

Slope compensation

SHDN