Automotive-Grade, Constant-Current 2.0 A

PWM Dimmable Synchronous Buck LED Driver

ALT80800

6

Allegro MicroSystems, LLC

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Characteristics

Symbol

Test Conditions

Min.

Typ.

Max.

Unit

ANALOG DIMMING INPUT

Input Voltage for 100% LED Current

2.1

–

–

V

Regulation Threshold at 50% Analog

Dimming

–

100

–

mV

Regulaton Threshold at 20% Analog

Dimming

38.4

40

41.4

mV

FAULT

LED Open/Short Detect Condition

ADIM Range

244

264

284

mV

LED Short Fault Output Voltage Low

Threshold

1.3

1.5

1.7

V

LED Open-Fault Enable Reference

2.352

2.4

2.448

V

LED Open Fault Current Threshold

(20 mV)

10%

(50 mV)

25%

(80 mV)

40%

–

(6 mV)

3%

(12 mV)

6%

(18 mV)

9%

–

Fault Deglitch Timer

35

50

65

µs

Fault Mask Timer

70

100

130

µs

FFn Pull-Down Voltage

–

–

0.4

V

FFn Pin Leakage Current

–

–

1

µA

The transition time FFn pin takes from Low

to High

–

–

10

µs

The transition time FFn pin takes from High

to Low

–

–

10

µs

Cool Down Timer for Fault Retry

–

1

–

ms

THERMAL SHUTDOWN

150

165

180

°C

Thermal Shutdown Hysteresis

–

25

–

°C

[1]

Determined by design and characterization. Not production tested.

[2]

Guaranteed by design, HS and LS switches are interlocked, as illustrated below:

SW

[3]

[4]

Negative current is defined as coming out of (sourcing) the specified device pin or node.