3

FN6626.0

December 17, 2007

.

Feedback Overvoltage Fault

220

250

300

mV

Switching Frequency

800

1000

1150

kHz

Maximum Recommended PWM

Dimming Frequency

Mode = 1, modulation signal applied to EN/PWM

10

kHz

Load Switch Transition Time

100

ns

Load Switch Driver Impedance Low

EN/PWM = 0

30

50

Ω

EN/PWM = 3V

30

52

Ω

Fault Timer Period

40

50

60

ms

Start-up Delay

Timed LX switching delay

0.85

1

1.24

ms

6

V

Boost Mode Threshold

BUCK/BOOSTN = GND

V

Buck Mode Threshold

V

Mode Low Threshold

MODE = GND

V

Mode High Threshold

V

Input Level Applied to TMAX Pin to

Enable Fault Protection

V

Input Level Applied to TMAX Pin to

Disable Fault Protection

V

Input Level Applied to TEMP Pin to

Enable Temperature Compensation

0.5

V

Input Level Applied to TEMP Pin to

Disable Temperature Compensation

0.08

V

VFB Positive Temperature

Compensation; VFB/VFBnom

VTEMP/VDC = 0.80

1.26

VFB Negative Temperature

Compensation; VFB/VFBnom

VTEMP/VDC = 0.20

0.74

Internal Temperature Protection

Threshold

135

°C

Internal Temperature Protection

Hysteresis

25

°C

EN/PWM Pin Input Low Threshold

1.2

V

EN/PWM Pin Input High Threshold

2.5

V

2.6

V

Internal Schottky Diode for Buck

15

23

Ω

Electrical Specifications

PARAMETER

DESCRIPTION

CONDITIONS

MIN

TYP

MAX

UNIT

MODE

TEMP

OPERATING MODE

1

(VDC - 0.25) > V > 0.25V Standard Mode light level to PWM modulation of EN/PWM input; LED bias current determined by

LEVEL voltage, nominal 1V

Don’t Care

V < 0.25V

Disable temperature compensation

0

V < (VDC - 0.25)

ISL78100