LT1952IGN datasheet(4/24 Pages) LINER

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LT1952

1952f

ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. COMP = open, FB = 1.4V, ROSC = 178k, SYNC = 0V, SS_MAXDC = VREF,

VREF = 0.1µF, SD_VSEC = 2V, BLANK = 40k, DELAY = 40k, ISENSE = 0V, OC = 0V, OUT = 1nF, VIN = 15V, SOUT = open, unless otherwise

specified.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.

Note 2: The LT1952EGN 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

LT1952IGN is guaranteed over the full –40°C to 125°C operating junction

temperature range.

Note 3: Rise and Fall times are measured at 10% and 90% levels.

Note 4: Guaranteed by correlation to static test.

Note 5: This IC includes over-temperature protection that is intended to

protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when over-temperature protection is active.

Continuous operation above the specified maximum operating junction

temperature may impair device reliability.

Note 6: Guaranteed but not tested.

Note 7: Maximum recommended SYNC frequency = 500kHz.

Note 8: In applications where the VIN pin is supplied via an external RC

network from a SYSTEM VIN > 25V, an external zener with clamp voltage

VIN ON(MAX) < VZ < 25V should be connected from the VIN pin to ground.

Note 9: VIN start-up current is measured at VIN = VIN ON – 0.25V and

scaled by x 1.18 (to correlate to worst case VIN start-up current at VIN ON).

Note 10: Timing for R = 40k derived from measurement with R = 240k.

OUT Max Duty Cycle

COMP = 2.5V, FB = 1V, RDELAY = 10k

(fOSC = 200kHz)

SD_VSEC = 1.4V, SS_MAXDC = VREF

OUT Max Duty Cycle Clamp

COMP = 2.5V, FB = 1V, RDELAY = 10k

(fOSC = 200kHz)

SD_VSEC = 1.32V, SS_MAXDC = 1.84V

63.5

80.5

SD_VSEC = 2.64V, SS_MAXDC = 1.84V

SOFT-START

SS_MAXDC Low Level: VOL

I(SS_MAXDC) = 150µA, OC = 1V

0.2

SS_MAXDC Soft-Start Reset Threshold

Measured on SS_MAXDC

0.45

SS_MAXDC Active Threshold

FB = 1V, DC > 0%

0.8

SS_MAXDC Input Current (Soft-Start Pulldown: Idis)

SS_MAXDC = 1V, SD_VSEC = 1.4V, OC = 1V

800

µA

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