LT3477 datasheet(4/26 Pages) AD

4 / 26 page

LT3950

Rev. 0

For more information www.analog.com

Note 1: Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Rating condition for extended periods may affect device

reliability and lifetime.

Note 2: Do not apply a positive or negative voltage to INTVCC, PWMTG, or

RT pin, otherwise permanent damage may occur. Use these pins only as

directed in the Pin Functions and Applications Information sections.

Note 3: The LT3950E is guaranteed to meet performance specifications

from 0°C to 125°C junction temperature. Specifications over the −40°C

to 125°C operating junction temperature range are assured by design,

characterization and correlation with statistical process controls. The

ELECTRICAL CHARACTERISTICS

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

SYNC/SPRD Threshold (Rising)

0.85

SYNC/SPRD Hysteresis

SYNC/SPRD Internal Pull-Down Resistance

100

kΩ

Minimum SYNC Pulse Width

Power Switch

RDS(ON)

ISW = 500mA

200

mΩ

Switch Current Limit

1.5

1.65

1.8

Switch Leakage Current

VSW = 60V, EN/UVLO = 0V

µA

External PMOS Driver

PWMTG ON (VISP – VPWMTG) Voltage

7.5

PWMTG OFF (VISP – VPWMTG) Voltage

0.3

Turn-on Time

CLOAD = 470pF

100

Turn-off Time

CLOAD = 470pF

100

Fault Detection and Reporting

LED Open Threshold

VISP – VISN = 0

VFB

– 37mV

VFB

– 23mV

VFB

– 9mV

FB Overvoltage Threshold

VFB

+ 60mV

VFB

+ 80mV

VFB

+ 100mV

FB Shorted LED Threshold

300

330

Overcurrent Protection Threshold (VISP – VISN)

VISP = 60V

600

700

800

FAULT Pin Pull Down Current

VFAULT = 0.2V, VFB = 1.25V

FAULT Pin Leakage Current

VFAULT = 3V, VFB = 0.7V

–100

100

Internal PWM Generator

PWM Pin Voltage for Max. Duty Ratio

1.2

PWM Pin Voltage for Min. Duty Ratio

0.2

Min. Duty Ratio

VPWM = 0.2V

0.78

Max. Duty Ratio

VPWM = 1.2V

100

PWM Pin Voltage Step per Duty Ratio Setting

7.8

PWM Pin Current

PWM = 3V

–100

100

PWM Clock Frequency

RP = 100k

400

Fraction of INTVCC for 10% Duty Ratio

27.2

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. Unless otherwise noted, VIN = EN/UVLO = 12V, FAULT = 100kΩ to 12V,

ISP = ISN = 48V, SYNC/SPRD = 0V, CTRL = 1.5V, PWM = 3V, INTVCC = 1μF to GND, RT = 45.3kΩ to GND, RP = 100kΩ to GND, FB = 1V.

LT3950J is guaranteed over the −40°C to 150°C operating junction

temperature range. Operating lifetime is derated at junction temperatures

greater than 125°C.

Note 4: LED Amplifier parameters measured in a servo loop with VC.

Note 5: This IC includes overtemperature protection that is intended to

protect the device during momentary overload conditions. The maximum

rated junction temperature will be exceeded when this protection is active.

Continuous operation above the specified absolute maximum operating

junction temperature may impair device reliability or permanently damage

the device.

LT3477 Datasheet(PDF) 4 Page - Analog Devices

LT3477 Datasheet(HTML) 4 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Datasheet Download

Link URL