2

Worcester, Massachusetts 01615-0036 (508) 853-5000

115 Northeast Cutoff, Box 15036

www.allegromicro.com

A8430

White LED Driver Constant Current Step-up Converter

Characteristics

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Input Voltage Range

–

2.5

–

10

V

Supply Current

–

2.5

3.5

mA

Shutdown (EN = 0 V)

–

0.1

1

µA

Feedback Reference Voltage

–

86

95

104

mV

Feedback Input Current

–

–

20

75

nA

Switch Current Limit

–

–

300

–

mA

Switch Frequency

–

0.8

1.2

1.6

MHz

Switch Maximum Duty Cycle

D

–

85

90

–

%

Switch Saturation voltage

–

–

350

–

mV

Switch Leakage Current

––

–

5

µA

Enable Input

Input Threshold Low

–

–

–

0.4

V

Input Threshold High

–

1.5

–

–

V

Input Leakage

Leakage

––

1

µA

Note 1. Measured with 4-layer PCB. Please refer to application note “Package Thermal Characteristics,“ for thermal perfor-

mance measurement for 3 mm x 3 mm MLP package for additional information.

Functional Block Diagram

VIN

FB

SW

1.25 V

GND

Driver

A2

S

Ramp

Generator

1.2 MHz

Oscillator

R

C

C

C

A1

95 mV

Enable

EN

Σ

RQ